BIOLOGY 1040 This post is dedicated to the class of Biology 1040: Environmental Studies (30893/EE1) NOVA SOUTHEASTERN UNIVERSITY, 2008.
Professor Jose Luis Jimenez IN THIS SITE THE CLASS WILL POST THEIR COMMENTS, QUESTIONS, EDUCATIONAL MATERIALS AND INTERACT WITH EACH OTHER WITH THE GOAL TO EDUCATE ALL THE READERS THAT VISIT THIS SITE ABOUT ISSUES RELATED TO ENVIRONMENTAL STUDIES.
Professor Jose Luis Jimenez IN THIS SITE THE CLASS WILL POST THEIR COMMENTS, QUESTIONS, EDUCATIONAL MATERIALS AND INTERACT WITH EACH OTHER WITH THE GOAL TO EDUCATE ALL THE READERS THAT VISIT THIS SITE ABOUT ISSUES RELATED TO ENVIRONMENTAL STUDIES.
Natacha Revelus
Bio. 1040
Turtles & Tortoises
When you think of the phrases: battle of the fittest or only the strongest survive, does evolution come to mind? Well, for me I always think about Darwin and his Theory of Evolution. Darwin Galapagos Islands was a major scientific break-through. It helped shaped a lot of ideas and hypothesis about evolution of mankind and animals alike. Although the theory of evolution was not new, Darwin Darwin Darwin
The Galapagos tortoise most closely resembled the South American tortoises; isolated on these remote islands, these tortoises has evolved distinctive forms (Johnson, 1998-2008). ���Of course, because of adaptation to localized habitats, island forms are not identical to those on the nearby continents. The turtles have evolved different shell shapes, for example; those living in moist habitats have dome-shaped shells while others living in dry places have low, saddle-backed shells with the front of the shell bent up to expose the head and neck��� (Johnson, 1998-2008).
This example is relevant to the exercise that we conducted in class. The 8 turtles and tortoises that we introduced to us in class share some of the same characteristics as the ones studied by Darwin Texas
The Russian tortoise of course is a land animal. It���s a vegetarian. These tortoises have a distinctive shell that���s usually a ruddy brown or black, fading to yellow between the scutes. The male in this species has a long tail that is tucked to the side and females have a short tail. However the females grow slightly larger than the males. Upon observing this animal we noticed that the snout is somewhat beak-shaped and it has very long claws which can be used for digging. According to Wikipedia, they are avid burrowers and can dig large burrows that might be two meters (several feet) long (Wikipedia, 2008). This tortoise was also observed to be agile and fast-paced.
The Red-foot tortoise is a native of South America . It is named from the red or orange scales on its limbs and also on its head and tail. They can live in a variety of habitats including grasslands and but prefer humid forested areas (Wikipedia, 2008). Being primarily a forest dweller, they have evolved a high domed narrow width carapace to facilitate getting between narrow openings of trees and vegetation in the rain forest (Wikipedia, 2008). Males in this species have a concave shaped shell and a much longer pointed tail which makes it easy for them to mate, the females, on the other hand, have a flat shaped shell and a stubby tail. In the case of evolution, red-foot tortoises are very sensitive to environmental changes. When first introduced to a new environment they will go for long periods of time without eating. It is not until they feel comfortable in their new environment, that they will start eating again. We observed that they have a short snout and that is good for eating most vegetables and fruits, especially dark green leafy vegetables (Wikipedia, 2008).
Our colorful friend the Central American Ornate Wood Turtle is another one that is adaptive enough to live both in water and on land. They like to live shallow waters but if in captivity can also live on damped sand and cypress mulch, sheets of bark and piles of hay or leaves which adds secure hiding places for it (Animal-World, 1998-2008). There is quite a variation of color along this species. Those from southern Nicaragua Costa Rica
The yellow-foot tortoise is the larger cousin of the red-foot tortoise. This name is derived from its several yellow head scales and its carapace is black with a small, distinct yellow area around the areola on each shell scale (Wikipedia, 2008). The adult males are bigger than the females however they are also much lighter than the females. Like the one we had in class, mature yellow-foots have distinctive incurving on the side of their shells, giving them a well-defined ���waist��� (Wikipedia, 2008). In addition, the plastron is extremely concave in males which make it easy for him to mate with the female who has a very flat plastron and short stubby tail. These species are found in the drier forest areas, grasslands, and the savanna, or the rainforest belts adjoining more open habitats (Wikipedia, 2008). Because of their considerably short neck and snout, the yellow foot���s diet consist of grasses, fallen fruits, plants, and any slow moving animals like snails, worms, and others that they are able to capture (Wikipedia, 2008); as you���ve probably have already guessed these creatures do not move fats at all compared to the other tortoises that we observed. This species has a very interesting evolutionary trait; it is interesting to note than in almost every tortoise species where male combat occurs, the males are always larger than the females. This is in comparison to aquatic species, where the males are usually smaller than the females and do not engage in male to male combat. It is thought that species with male combat evolved larger males because larger males have a better chance of winning a bout and mating with a female, thus passing on their larger size to their offspring. Species with smaller males evolved because smaller males are more mobile and can mate with a large number of females, thus passing on their genes (Wikipedia, 2008). Now that���s survival for ya!
The last turtle observed was the only true full water turtle: the mudd turtle from North America. This little creature prefers to live in shallow, slow moving bodies of water with muddy bottoms. Also they have a dome shaped carapace (Wikipedia, 2008). Even though they are small they can live up to 50 years old! It���s known for it���s dull shell and has a black under belly which helps it to camoflague well in seaweed, protecting it against predators. Also, this little guy is carnivorious, and will consume almost anything they can catch including small fish, worms, insects, grubs, crustaceans, tadpoles, small berries and even carrion. In this species the females are generally larger than the males but the males have a much longer tail, furthermore they can be black, brown, green or yellowish in color (Wikipedia, 2008).
Each of the turtles observed had their own specific traits and characteristics for survival and battle of the fittest. A lot of them have overcome the natural selection process because they are so adaptive, hence the turtles and tortoises that can live in both water and on land. Shell size, snout size, length of neck and mobility all play a major role in determinig which species can and will outlive the other and has the strongest genes/characteristics to pass on to the next generation.
Works Cited
Wednesday, April 23, 2008
FINAL ESSAY
Darwin and Natural Selection (Evolution)Most educated people in Europe and the Americas during the 19th century had their first full exposure to the concept of evolution through the writings of Charles Darwin . Clearly, he did not invent the idea. That happened long before he was born. However, he carried out the necessary research to conclusively document that evolution has occurred and then made the idea acceptable for scientists and the general public. This was not easy since the idea of evolution had been strongly associated with radical scientific and political views coming out of post-revolutionary France . These ideas were widely considered to be a threat to the established social and political order.It was during the beginning of the voyage that Darwin read the early books of Charles Lyell and became convinced by his proof that uniformitarianism provided the correct understanding of the earth's geological history. This intellectual preparation along with his research on the voyage were critical in leading Darwin to accept evolution. Especially important to the development of this understanding was his 5 weeks long visit to the Gal��pagos Islands in the Eastern Pacific Ocean . It was there that he began to comprehend what causes plants and animals to evolve, but he apparently did not clearly formulate his views on this until 1837.The Gal��pagos Islands have species found in no other part of the world, though similar ones exist on the west coast of South America . Darwin was struck by the fact that the birds were slightly different from one island to another. He realized that the key to why this difference existed was connected with the fact that the various species live in different kinds of environmentsDarwin identified 13 species of finches in the Gal��pagos Islands . This was puzzling since he knew of only one species of this bird on the mainland of South America , nearly 600 miles to the east, where they had all presumably originated. He observed that the Gal��pagos species differed from each other in beak size and shape. He also noted that the beak varieties were associated with diets based on different foods. He concluded that when the original South American finches reached the islands, they dispersed to different environments where they had to adapt to different conditions. Over many generations, they changed anatomically in ways that allowed them to get enough food and survive to reproduce.Today we use the term adaptive radiation to refer to this sort of branching evolution in which different populations of a species become reproductively isolated from each other by adapting to different ecological niches and eventually become separate species.Darwin came to understand that any population consists of individuals that are all slightly different from one another. Those individuals having a variation that gives them an advantage in staying alive long enough to successfully reproduce are the ones that pass on their traits more frequently to the next generation. Subsequently, their traits become more common and the population evolves. Darwin called this "descent with modification."The Gal��pagos finches provide an excellent example of this process. Among the birds that ended up in arid environments, the ones with beaks better suited for eating cactus got more food. As a result, they were in better condition to mate. Similarly, those with beak shapes that were better suited to getting nectar from flowers or eating hard seeds in other environments were at an advantage there. In a very real sense, nature selected the best adapted varieties to survive and to reproduce. This process has come to be known as natural selection.Darwin did not believe that the environment was producing the variation within the finch populations. He correctly thought that the variation already existed and that nature just selected for the most suitable beak shape and against less useful onesBoth Darwin and Wallace failed to understand an important aspect of natural selection. They realized that plant and animal populations are composed of individuals that vary from each other in physical form. They also understood that nature selects from the existing varieties those traits that are most suited to their environment. If natural selection were the only process occurring, each generation should have less variation until all members of a population are essentially identical, or clones of each other. That does not happen. Each new generation has new variations. Darwin was aware of this fact, but he did not understand what caused the variation. The first person to begin to grasp why this happens was an obscure Central European monk named Gregor Mendel . Through plant breeding experiments carried out between 1856 and 1863, he discovered that there is a recombination of parental traits in offspring. We will let Julian Huxley sum up Darwin 's place in the history of science:" Darwin 's work ... put the world of life into the domain of natural law. It was no longer necessary or possible to imagine that every kind of animal or plant had been specially created, nor that the beautiful and ingenious devices by which they get their food or escape their enemies have been thought out by some supernatural power, or that there is any conscious purpose behind the evolutionary process. If the idea of natural selection holds good, then animals and plants and man himself have become what they are by natural causes, as blind and automatic as those which go to mould the shape of a mountain, or make the earth and the other planets move in ellipses round the sun. The blind struggle for existence, the blind process of heredity, automatically result in the selection of the best adapted types, and a steady evolution of the stock in the direction of progress...Darwin 's work has enabled us to see the position of man and of our present civilization in a truer light. Man is not a finished product incapable of further progress. He has a long history behind him, and it is a history not of a fall, but of an ascent. And he has the possibility of further progressive evolution before him. Further, in the light of evolution we learn to be more patient. The few thousand years of recorded history are nothing compared to the million years during which man has been on earth, and the thousand million years of life's progress. And we can afford to be patient when the astronomers assure us of at least another thousand million years ahead of us in which to carry evolution onwards to new heights."NOTE: The phrase "survival of the fittest" was apparently first used in 1851 by the influential British philosopher Herbert Spencer (1820-1903) as a central tenet of what later became known as "Social Darwinism." He misapplied Darwin 's idea of natural selection to justify European domination and colonization of much of the rest of the world. Social Darwinism was also widely used to defend the unequal distribution of wealth and power in Europe and North America at the time. Poor and politically powerless people were thought to have been failures in the natural competition for survival. Subsequently, helping them was seen as a waste of time and counter to nature. From this perspective, rich and powerful people did not need to feel ashamed of their advantages because their success was proof that they were the most fit in this competition. Despite misgivings by Alfred Wallace and other naturalists, Charles Darwin began to use "survival of the fittest" as a synonym for "natural selection" in the 5th edition of Origin of Species, which was published in 1869.http://anthro.palomar.edu/evolve/evolve_2.htm (Darwin and Natural Selection)http://www.blupete.com/Literature/Biographies/Science/Darwin.htm (The Scientist: Charles Darwin , Biography)History and Evolution of TurtlesReptiles became part of the evolutionary scene approximately 300 million years ago at the end of the Paleozoic Era. Whereas, the first turtle fossil wasn't discovered until about 80 million years later during the Triassic period, which was the beginning of the Age of Reptiles. The first fossil was that of Proganochelys, a freshwater, much larger version of modern day snapping turtles. There is quite a mystery surrounding turtle evolution; it is thought that it happened in a relatively short time due to minimal fossil evidence leading up to the find of Proganochelys. It is thought that a minute change in genetic composition could lead to the creation of a carapace and plastron, thus a small genetic change could have lead to a huge evolutionary advantage. (Spotilla, 2004) During the Mesozoic Era turtles went back and forth between land and sea many times, and it wasn't until about 120 million years ago during the Cretaceous period that modern sea turtles evolved. Thus, flippers and other sorts of evolutionary advantages didn't result until that time.At the end of the Mesozoic there was a huge mass extinction, possibly the most well-known of all mass extinctions due to the loss of the dinosaurs. After the mass extinction approximately 66 million years ago, the Age of Reptiles gave way to the Age of Mammals. The reptiles that faired the best during and after the extinction were perhaps the sea going turtles. Four families of sea turtles survived, Toxochelyidae, Protostegidae, Cheloniidae and Dermochelyidae. The former two families have since become extinct, Toxochelyidae during the Eocene epoch and Protostegidae during the Oligocene epoch. There are currently seven species of sea turtles swimming in the oceans, six of which are in the family Cheloniidae, the other is the solitary member of the Dermochelyidae family. This paper will compare four of the seven sea turtle species, leatherbacks, loggerheads, greens and hawksbills. All are from the Cheloniidae family with the exception of the leatherback which is from Dermochelyidae.References1. Broward County Florida-Biological Resources Division. (n.d.)Sea turtle conservation program. Retrieved February 9, 2005 from http://www.co.broward.fl.us/bri00600.htm 2. Caribbean Conservation Corporation and Sea Turtle Survival League. (2005) Species Fact Sheets. Retreived June 5, 2005 from http://www.cccturtle.org/contents.html3. Jones, A. (2004) Sea turtles: old viruses and new tricks. Current Biology, 14, R842-R843. 4. Lewison, R., Crowder, L., Read, A., & Freeman, S. (2004) Understanding impacts of fisheries bycatch on marine megafauna. TRENDS in Ecology and Evolution, 19 (11), 598-604. 5. National Oceanic and Atmospheric Administration-Office of Protected Resources. (n.d.) Marine Turtles. Retrieved February 2, 2005 from http://www.nmfs.noaa.gov/pr/species/turtles
Posted by Tmoultrie
Malika Cox
EVOLUTION AND THE TURTLE/TORTOISE
(applying Darwin's theory)
"In the struggle for survival, the fittest win out at the expense of their rivals because they succeed in adapting themselves best to their environment." (Charles Darwin)
Darwin's Theory of Evolution had never been of any real interest to me personally. Because of my religious beliefs I would quickly resist any talk about evolution, big bang theory, etc. However, the above quote by Darwin strongly caught my attention. As I began to read about it there are views that I do not agree with but others that I do. This post however excludes any personal views that I may have and strictly applies the theory of Evolution as it pertains to turtles and tortoises. A total of eight (8) turtles were observed and researched: the Box Turtle, Russian Tortoise, Red Foot Tortoise, Central America Wood Turtle, the Yellow Foot Tortoise, and the Mud Turtle. During observation there were noticeable differences physically. Differences in color, neck length, mouth (rounded/pointed, sharp/not sharp), texture of shell, tail length, legs (some thick, some not so), webbed feet and non webbed feet, curved and straight claws. So what is the reason for all of the variations of characteristics? This is the essence of what the Darwin theory is about.
For starters we must understand Darwin and this very popular theory of his. The premise of Darwin's theory of Evolution is that all life is related and has descended from a common ancestor. Darwin's general theory presumes the development of life from non-life and stresses a purely naturalistic (undirected) "descent with modification". That is, complex creatures evolve from more simplistic ancestors naturally over time. In a nutshell, as random genetic mutations occur within an organism's genetic code, the beneficial mutations are preserved because they aid survival -- a process known as "natural selection." These beneficial mutations are passed on to the next generation. Over time, beneficial mutations accumulate and the result is an entirely different organism (not just a variation of the original, but an entirely different creature). According to the great biologist Ernst Mayr, these observations have been amply demonstrated in biology, and even fossils demonstrate the veracity of these observations. In lamens terms, biology and fossils prove this idea to be true. The main idea in the theory is Natural Selection. To simplify, Natural selection (a slow process)is the preservation of a functional advantage that enables a species to compete better in the wild. With that stated let's see how this applies to our little friends.
I must admit, I didn't think that this assignment would be of any real interest being that I've never before been interested in knowing anything about turtles. Having to begin this quest while being under the weather did not make it any better either. However, the more information I gathered, the more interesting it became. Specifically, the turtle with the most revealing information and the one that really started my "juices flowing" was the Russian Tortoise.
In-class observation:
color: light green w/ black spots (with no hinge for closure)-- this is possibly to aid in camouflaging against predators. The reason I say this is because the color is a little bland and this tortoise is found in dry open landscapes, sand and clay deserts with sparse grasses and brushes, rocky deserts also and hillsides. These types of areas are not generally colorful. So had the tortoise been colorful it would stand out tremendously!
long straight claws and non-webbed feet: no web needed as this is a land turtle and the claws are straight because they burrow in sandy or loamy burrows. Meaning the soil is not stiff which means no need for the curved claws used for real digging.
long neck: during courtship he male approached female and repeatedly circles her. Then he stops, faces her head on and extends his neck and rapidly jerks up and down. If he had a short neck he wouldn't be able to extend and practice this ritual.
diet: the Russian Turtle is active but slows down in June and July (summer), leaving the burrow only dawn or dusk. The reason is that the summer temperatures that exceed 85 degrees Fahrenheit are problematic for them. So they "chill" during the summer. What does this have to do with what they eat? Well, what a coincidence it is that at summer's end, they feed on dried grasses and twigs! What else is available after hot summers in the deserts? Surprisingly enough in habitat, they feed on vegetation, flowers, twigs and fruits. Now that's survival for you! Oh, what about water? Well during rainy seasons, they drink water from puddles that form but while they are chilling in the summer, they rely on metabolic water (hold their urine until the rainy season).
The YELLOW FOOT TORTOISE
size: female is larger than male. The reason for this is that the larger the female, the more eggs it produces.
mouth: rounded, not sharp. This is possibly because of it's diet. This tortoise feeds on grasses, fallen fruit, plants, mushrooms, snails, worms, and other slow moving animals. A sharp mouth is not needed for this type of diet, nothing to rip or tear really.
feet: feet are non-webbed because it dwells on land.
THE MUD TURTLE:
claws: claws are curved. This characteristic is essential since the mud turtle hibernates in the mud which of course is more stiff than sand or softer soil.
feet: feet are webbed as these turtles do swim
mouth: pointed/sharp. This more than likely is due to the type of diet that this turtle indulges in. Wonderful items on the menu are: insects, tadpoles, and fish.
THE BOX TURTLE:
Now this turtle has of course oen or more of the characteristics of the others. We all know that they will have either webbed or non-webbed feet, curved or straight claws, colorful or non-colorful or bland shell, etc. The main characteristic I would like to note about this turtle is one that none of the others possess and that is the fact that the shell has a "hinge". The hinge allows the turtle to retract its legs and close the front and hind part of ots shell. Why is this so? As I looked through different sources I tried to find information that would elude to why this is so. The only item that stood out to me is the the purpose of this is to "protect against predators". Now this is sort of common sense, but why wasn't this piece of information present in the description of all the others. I think I may know why. One itme that this mentioned about this turtle that is not in y research of all the others is that this is the SLOWEST REPRODUCING species in the world. So while the others can hide under brushes and in the mud and under trees, this species is so precious that it must take extra procautions and not just depend on outer elements to aid in prolonging its existence but needed a true protector from its own body.
Conducting these observations and research was very enlightening. For me it shd some light on more than just turtles and tortoises. It taught me a little more about life and how this idea of the "survival of the fittest" applies to us as humans truly! If a turtle can adapt and persevere and be tenacious as they are, surely we can too. I leave you with a culminating quote from the great scientist Ernst Mayr:
Darwin imagined it might be possible that all life is descended from an original species from ancient times. DNA evidence supports this idea.
Probably all organic beings which have ever lived on this earth have descended from some one primordial life form. There is grandeur in this view of life that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.
EVOLUTION AND THE TURTLE/TORTOISE
(applying Darwin's theory)
"In the struggle for survival, the fittest win out at the expense of their rivals because they succeed in adapting themselves best to their environment." (Charles Darwin)
Darwin's Theory of Evolution had never been of any real interest to me personally. Because of my religious beliefs I would quickly resist any talk about evolution, big bang theory, etc. However, the above quote by Darwin strongly caught my attention. As I began to read about it there are views that I do not agree with but others that I do. This post however excludes any personal views that I may have and strictly applies the theory of Evolution as it pertains to turtles and tortoises. A total of eight (8) turtles were observed and researched: the Box Turtle, Russian Tortoise, Red Foot Tortoise, Central America Wood Turtle, the Yellow Foot Tortoise, and the Mud Turtle. During observation there were noticeable differences physically. Differences in color, neck length, mouth (rounded/pointed, sharp/not sharp), texture of shell, tail length, legs (some thick, some not so), webbed feet and non webbed feet, curved and straight claws. So what is the reason for all of the variations of characteristics? This is the essence of what the Darwin theory is about.
For starters we must understand Darwin and this very popular theory of his. The premise of Darwin's theory of Evolution is that all life is related and has descended from a common ancestor. Darwin's general theory presumes the development of life from non-life and stresses a purely naturalistic (undirected) "descent with modification". That is, complex creatures evolve from more simplistic ancestors naturally over time. In a nutshell, as random genetic mutations occur within an organism's genetic code, the beneficial mutations are preserved because they aid survival -- a process known as "natural selection." These beneficial mutations are passed on to the next generation. Over time, beneficial mutations accumulate and the result is an entirely different organism (not just a variation of the original, but an entirely different creature). According to the great biologist Ernst Mayr, these observations have been amply demonstrated in biology, and even fossils demonstrate the veracity of these observations. In lamens terms, biology and fossils prove this idea to be true. The main idea in the theory is Natural Selection. To simplify, Natural selection (a slow process)is the preservation of a functional advantage that enables a species to compete better in the wild. With that stated let's see how this applies to our little friends.
I must admit, I didn't think that this assignment would be of any real interest being that I've never before been interested in knowing anything about turtles. Having to begin this quest while being under the weather did not make it any better either. However, the more information I gathered, the more interesting it became. Specifically, the turtle with the most revealing information and the one that really started my "juices flowing" was the Russian Tortoise.
In-class observation:
color: light green w/ black spots (with no hinge for closure)-- this is possibly to aid in camouflaging against predators. The reason I say this is because the color is a little bland and this tortoise is found in dry open landscapes, sand and clay deserts with sparse grasses and brushes, rocky deserts also and hillsides. These types of areas are not generally colorful. So had the tortoise been colorful it would stand out tremendously!
long straight claws and non-webbed feet: no web needed as this is a land turtle and the claws are straight because they burrow in sandy or loamy burrows. Meaning the soil is not stiff which means no need for the curved claws used for real digging.
long neck: during courtship he male approached female and repeatedly circles her. Then he stops, faces her head on and extends his neck and rapidly jerks up and down. If he had a short neck he wouldn't be able to extend and practice this ritual.
diet: the Russian Turtle is active but slows down in June and July (summer), leaving the burrow only dawn or dusk. The reason is that the summer temperatures that exceed 85 degrees Fahrenheit are problematic for them. So they "chill" during the summer. What does this have to do with what they eat? Well, what a coincidence it is that at summer's end, they feed on dried grasses and twigs! What else is available after hot summers in the deserts? Surprisingly enough in habitat, they feed on vegetation, flowers, twigs and fruits. Now that's survival for you! Oh, what about water? Well during rainy seasons, they drink water from puddles that form but while they are chilling in the summer, they rely on metabolic water (hold their urine until the rainy season).
The YELLOW FOOT TORTOISE
size: female is larger than male. The reason for this is that the larger the female, the more eggs it produces.
mouth: rounded, not sharp. This is possibly because of it's diet. This tortoise feeds on grasses, fallen fruit, plants, mushrooms, snails, worms, and other slow moving animals. A sharp mouth is not needed for this type of diet, nothing to rip or tear really.
feet: feet are non-webbed because it dwells on land.
THE MUD TURTLE:
claws: claws are curved. This characteristic is essential since the mud turtle hibernates in the mud which of course is more stiff than sand or softer soil.
feet: feet are webbed as these turtles do swim
mouth: pointed/sharp. This more than likely is due to the type of diet that this turtle indulges in. Wonderful items on the menu are: insects, tadpoles, and fish.
THE BOX TURTLE:
Now this turtle has of course oen or more of the characteristics of the others. We all know that they will have either webbed or non-webbed feet, curved or straight claws, colorful or non-colorful or bland shell, etc. The main characteristic I would like to note about this turtle is one that none of the others possess and that is the fact that the shell has a "hinge". The hinge allows the turtle to retract its legs and close the front and hind part of ots shell. Why is this so? As I looked through different sources I tried to find information that would elude to why this is so. The only item that stood out to me is the the purpose of this is to "protect against predators". Now this is sort of common sense, but why wasn't this piece of information present in the description of all the others. I think I may know why. One itme that this mentioned about this turtle that is not in y research of all the others is that this is the SLOWEST REPRODUCING species in the world. So while the others can hide under brushes and in the mud and under trees, this species is so precious that it must take extra procautions and not just depend on outer elements to aid in prolonging its existence but needed a true protector from its own body.
Conducting these observations and research was very enlightening. For me it shd some light on more than just turtles and tortoises. It taught me a little more about life and how this idea of the "survival of the fittest" applies to us as humans truly! If a turtle can adapt and persevere and be tenacious as they are, surely we can too. I leave you with a culminating quote from the great scientist Ernst Mayr:
Darwin imagined it might be possible that all life is descended from an original species from ancient times. DNA evidence supports this idea.
Probably all organic beings which have ever lived on this earth have descended from some one primordial life form. There is grandeur in this view of life that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.
24 comments:
South America (Colombia and Ecuador)
10 Social Problems
1. Drugs
2. Guerrilla
3. Poverty
4. Poor Public Education
5. Social Apathy
6. Political Corruption
7. Poor Emergency Medical Systems
8. Regionalism
9. Segregation of Socila Classes
10. Illiteracy
10 Environmental Problems
1. Pollution
2. Lack of laws and regulations/ not enforced
3. No Recycling
4. No Emission Controls
5. No Beach Maintenance
6. No Hunting Regulations
7. Poor Rainforest Conservations
8. Lack of environmental education
9. Contaminated Water
10. Deforestation
10 Social Issues
-Standards of living
-Lack of Authority
-Lack of Education
-lack of Transportation
-High Crimes
-Drugs
-Technology
-Davaluation of Money
-lack of Infurstration
-Lack of Health Insurance
10 Enviromental Issues
-Deforestation
-Lack of clean water
-Garbage
-Bad Road Constrution
-Decrease of natural resources
-Decrease of outsources
-Electricity
-Estint of animal and plant
-Plan of evacuation
-Air Pollution
England & Norway (Europe)
Nicole & Nina
10 Social Issues:
-Drugs/Alcohol
-Gender Inequality (Men still earn more money than women for doing the same job)
-Racism (Immigrants)
-Violence/Abuse
-Weapons
-Smoking
-Prostitution
-Gay/Lesbian Rights
-Benefits (Welfare)
-High Taxes
10 Environmental Issues:
-GLOBAL WARMING!!!
-Whale Hunting
-Fox Hunting
-Wolves or Sheep?
-Car Pollution/Car Pooling
-Public Transportation
-Energy From Wind/Water
-Nuclear Power Stations
-Recycling
-Oil
TEAM AMERICA
10 SOCIAL ISSUES
1. waste management (landfills,excessive product packaging)
2. water consumption
3. consumerism (deforestation)
4. drug/alcohol abuse
5. unemployment rate
6. population (high birth rate)
7. STDs
8. poverty
9. environmental racism
10. health coverage
10 ENVIRONMENTAL ISSUES
1. water pollution (rx and toxins in water supply)
2. air pollution
3. habitat (displacement of animals)
4. drought
5. overconsumption of fossil fuels
6. deforestation
7. slums
8. nuclear radiation
9. overconsumption of petroleum
10. overpopulation of exotic animals
Nicole Velez South America Group
To target poor public education and illiteracy, our group found a few solutions:
- to bring in international organizations and outsource the teaching with a few of the following:
-international reading association
-National Association for the education of young children
-promote government awareness
-create relationships with lottery and charity events
To tackle the problem of lack of environmental education, we decided to promote with:
-a concert conveying the message
-creating a global standard to set limitations to damages caused by U.S. influences (similar to Kyoto)
-mandatory TV show in which the president addresses specific situations
like-> the Al Gore documentary
-> celebrity speakers
-> this will unify the whole continent and hopefully soon, the world.
- creating a program in which the senior high schoolers must choose between teaching an illiterate child to read, going to a poor community and teach health awareness, and cleaning up a community while recycling.
to change the poor emergency medical systems, we can create small urgent care and enforce nursing in schools at all time
To tackle recycling, we can promote it through a recycling contest in which neighborhoods compete for cleanliness and we create a recycling system.
Darwin’s Theory of Evolution
Darwin’s theory of evolution, in it’s most basic form, is the idea that species of life have
evolved over time through the process of natural selection. This natural selection process is the
idea that stronger traits become more common in future generations of a species while weaker
traits become less common. Most of Darwin’s enlightenment for these theories came from his
work upon his five-year journey aboard the HMS Beagle. This journey led him to the Galapagos
Islands where he formed the foundation for his theories. Here he was able to study many
different species including birds, plants, and reptiles. These were species growing away from
the mainland and although they were located on islands right next to each other, he noticed
certain characteristics which differed from island to island on the same species. His only
explanation was that the species was gradually changing to adapt to it’s unique environment.
For example, Darwin illustrated certain beak variation on finches in the Galapagos islands. He
noted there were about 13 closely related species whose only major difference was found in
the shape of their beaks. This unique beak design made them better suited for their preferred
food. Darwin attributed this observation to Natural Selection.
In class we got the chance to study different species of turtles and tortoises. There were
8 in total. No 2 were exactly alike. They all had variations in color, mouth design, shell design,
feet, eyes, etc. It was later revealed to us what species we had been observing. The redfoot
tortoise, the box turtle, the russian tortoise, the central American ornate wood turtle, the
yellowfoot tortoise, and the mud turtle. After observing these animals and trying to draw our
own conclusions to explain their unique design, we were able to research the species to
confirm our theories. The redfoot tortoise is found in south America and lives in open
grasslands. This explains our observation of it’s long neck and it’s long claws. The neck which
may be used to reach higher grass and the long claws to dig into dirt for traction and speed.
It is also important to note that the females have a flat belly and the belly of the males is
slightly concave, this allows the male to mount the female for reproduction. The box turtle is
found in the united states and mexico. This species eats insects as well as plants which may
explain why the upper half of the mouth sticks out further than the bottom, maybe for cracking
through outer shells or things of that nature. The males usually are the more colorful ones and
the females the more plain in color. A unique defense mechanism found in this turtle
is the way that it can shut itself inside of it’s shell. This is possible because on the bottom shell,
towards the head, some flexibility is found. Almost like a hinge, it closes perfectly as it’s head
retrieves inside, the outer shells shuts and makes it difficult for penetration. Very aptly named,
the Russian tortoise, found in Russia, was another species we observed. We observed a very
long and visible tail, small black eyes, very long claws, and a very pointy mouth. Again, being a
herbivore, and sticking to dry land, it’s long claws I would say, help it best to dig around in that
dirt as it goes to and fro in the search of it’s next plant to devour. The central American ornate
turtle is a very interesting species. Although it is a turtle, and does swim, it spends most of it’s
time in very shallow water and can travel on land with ease. It’s very colorful, has a smaller
head, and eats fish. It has some webbing between its claws which probably come sin very handy
for swimming. The yellow foot tortoise is closely related to the redfoot tortoise. It is also native
to south America. This specific one we observed was very large. It’s feet were big, wide, and
massive almost like those of an elephant, making it very difficult for it to swim, probably
explaining why it lives in dry land. Finally, the last species observed in this group was the mud
turtle. This is a very small turtle. It is native to north America and is the only real turtle. It eats
fish and little worms. It’s feet are webbed, it has a pointy face, a big pointy shell, and a freckly
face. It is obvious that all of these species have many characteristics that vary. These variations
are probably very useful and necessary even for adapting to each one’s different environment.
Whether it be hunting or reproducing, every species has unique traits that are critical to it’s
survival. Darwin attributes this to natural selection, evolution, and survival of the fittest. I think
it’s important to note that is only a theory and while it is a very popular belief accepted by
many, many other people still hold strong to theory belief in intelligent design which also has
it’s very valid points and explanations for these species and their incredible make-up.
Whichever the belief though, one thing we can all agree on is to research so that we can do our
best to conserve these animals and their environment so that they will be around for many
more years to come.
April's Turtle Soup
Many thanks to April Barkulis for sharing her recipe.
~ 2 lb's turtle meat, cubed
~ 2 sticks unsalted butter
~ 1 cup all purpose flour
~ 1 cup diced celery
~ 2 cups diced yellow onions
~ 1 1/2 cups tomato puree
~ 1 quart beef stock
~ 6 hard boiled eggs, chopped fine
~ juice of one lemon
~ 3 bay leaves
~ 1/2 tsp oregano
~ 1/2 tsp thyme
~ 1 tsp black pepper
~ 3 tbsp minced parsley
~ salt and pepper to taste
In a heavy saucepan melt the butter. When melted, add the flour and cook until the flour turns the color of a penny.
This roux must be stirred at all times so it will not burn.
When roux reaches the desired color add the celery, onion and turtle meat. Cook until turtle is brown and vegetables are clear.
Add the tomato puree and simmer for 15 minutes.
In a stock pot, heat the beef stock to a boil.
When stock is boiling, add the mixture from your saucepan and stir until soup is mixed and roux is dissolved. Stock should be smooth and have body.
Simmer soup until turtle becomes tender. Add the lemon juice, diced eggs and parsley. Stir together.
Serve and Enjoy!
Many of us have different views on how man came to be, many of us think that the world was created in seven days and some of us think that we evolved. To understand how we came to be we must look at several different factors like how has the human species survived for so long dating back to pre-historic times. Then Darwin developed his theory of evolution which stated that all living things came from a simpler non-complex ancestor, which meant that we had evolved or mutated into our current forms. Now when most people think of mutation we think that it is a bad thing and that we are worse for it, but the reality of the situation is that Darwin believed that these mutations would help as adapt to our environment which meant the survival of our species. In our class we had the privilege of observing many different kinds of turtles and tortoises to see what Darwin was speaking of with the adaptation of each animal’s body to its natural environment.
To begin understanding all these different classes of turtles and tortoises we must understand what Darwin meant with his whole theory by breaking it down to its simplest form and seeing the change that he saw. First lets understand what he meant by Natural Selection which is the process by which animals who gain certain characteristics will survive because of the advantage of their certain mutations. More simply for example let us say there was a group of animals who had to travel great distances to obtain their food and over time one of those animals grew wings and learned to fly. Now this would significant because this animals would be able to cover greater distances at a much larger pace, and he would then pass on these traits to his offspring which would start to dominate the species that they grew off from thus wiping out the inferior species slowly but surely. Another example of this is the breeding of domestic animals which over time has come to create all the desired domestic species with all the traits one might desire in a domestic animal.
This process would be to great advantage to any species because it just ensures that a species must adapt to survive in this planet. You could even go as far to say that adaptation to one’s environment could be seen in today’s modern world. We all realize the rising cost of oil and it’s affect on our economic situation but did we ever wonder that right now we are adapting by creating cars that do not run solely on fossil fuels and at the same time addressing the rising concern of Global Warming and it’s affect on our climate change. Now it’s not as drastic as growing wings but it is a form of adaptation to our current environment and how we must live in it to ensure that this planet survives. We all adapt to our environment by wearing more clothes if it’s cold or less if it’s hot. This is something that we all do inherently because we know in our minds that we must do so to ensure that we all survive which is a form of self preservation.
We all might ask how Darwin came up with this theory of Natural Selection which came to be after his trip to the Galapagos Islands where he observed many different kinds of plant and animal species away from the mainland. At first he did not like the islands due to their appearance and did not realize the breakthrough he had found on the island for a couple of years after he left. He still believed that all animals were of the same inherent families, but it was a colleague of his by the name of John Gould who told him that the finches he had were not of the same family but a completely new family which he had discovered on the island on his excursion.
Darwin saw the difference in beak sizes between the finches which made them a perfect source of study for natural selection which was then confirmed some time after by later workers of the islands on their own mission to study this theory. Darwin also saw giant tortoises for the first time which we regarded as nothing more than an abundant food source on the island which they hunted and ate on the trip back to England. He also went back and left with a large load of tortoises which became extinct 10 years after he first got there due to the ships passing through and introduction of different animals that were starting to dominate the region which is why conservation of the islands grew to high importance.
Darwin then wrote a book with an accumulation of all that he had discovered from these islands called “On the Origin of Species” which was widely accepted by many scientist and seen as one of the most influential pieces of science ever written. The majority of people along with the church refuted these findings because at the time this was seen as something that was just not possible in any way but then confirmed and later accepted by many other. His ground breaking research led to the understanding of many different species on how they could have possibly turned into the forms of animals we see every day now.
In our class we were allowed to examine many different types of tortoises and turtles seeing the difference between them and making our own assumptions before we knew the true identity of every turtle/tortoise. This once again re-affirmed Darwin theory on how we all saw how all these different types of turtles belonged to the same species but had evolved to fit their surrounding environment to survive in it. Even as simple students we were able to depict the subtle difference in color, shape, size, texture, and aggressiveness between them. These findings were amazing to see because some turtles that looked identical ended up being very different and some turtles that didn’t even look alike had very common features due to them sharing the same type of environment.
Let me first start by explaining the difference between a turtle and a tortoise by discussing where they live. Turtles spend most of their time in or around water like oceans or freshwater because of how they are shaped. Their front feet are fins or usually webbed to allow them better movement in the water which is also accompanied by falter backs compared to tortoises. They like to mate and lay their eggs underwater or close shorelines and sometimes like to sun themselves on logs, rocks, or banks of rivers. They mostly eat plants, insects, and fish which are what is most abundant in their habitats causing them to be omnivorous.
Now let us speak about the tortoise which lives entirely above water only going to rivers to drink and clean themselves. They do not have fin or webbed feet like the turtle their feet are sometimes flat and rounded or have claws for digging which means they cannot swim and are prone to drowning if they fall in a river. They like to dig burrows which they climb inside of during hot sunny weather or when they like to sleep. They eat mostly shrubs and other plants which contain a lot of moisture making them mostly herbivores. Their shells are rounded domes so that they can pull in all their limbs in case of an attack by predators.
Now I will talk about the different types of turtles/tortoises that me and my classmates were allowed to examine. The first turtle I will speak about is the Florida Box turtle which has a hinged shell which allows it to completely close off its shell from outside intruders. They have a steep high dome rounded shell with a slightly hooked jaw and webbed feet. The males are typically larger than the females and have thicker and longer tails along with claws on their hind legs which are short, thick, and curved. In the summer season they are usually active only after rain showers or in the mornings and when it gets too hot they like to hide under decaying trees and in mud puddles or shady pools. Many do not know but box turtles may live past 100 years and are the more common pet turtle.
Next I will talk about the mud turtle which like many other turtles, mud turtles are omnivorous, and prefer damp, sandy, or muddy dwellings. Mud turtles rarely grow to sizes beyond 5 inches, and are therefore easy to keep indoors, or outdoors. Like most other turtles and reptiles, mud turtles love to bask in the sun's rays, and they can live to be over 50 years old, providing they can stay clear of predators. Mud turtles are known for their dull shell colors and relation to the smelly musk turtles. African and American mud turtles are very different and are not closely related. Their only similarities are in their choice of habitat, both preferring shallow, slow moving bodies of water with muddy bottoms, and having a dome shaped shell.
The next animal I will be speaking about is the Yellow-foot tortoise which is found in South America over a wide range from Bolivia through Brazil. This species is a rainforest species and as such its care requirements are more restrictive than those of the Red-foot. While the two species share habitats in some locations it appears that only the Red-foot tortoise will go out of the forest into the grasslands and brighter sunlight. The rainforest is typically seen as being a very stable environment, humidity is high, and temperature changes between night and days are fairly narrow. In addition to this, in rainforests the lighting is dim. It is these conditions that we seek to match when providing for Yellow-foots, providing a high humidity environment with night temperatures above 65 degrees F and day temperatures below 95 degrees F. Yellow-foots are less tolerant to very high temperatures than Red-foots, possibly because they have less tendency to wallow in shallow water and mud during times of extreme heat. They stress easily and providing a dim area such as large plants and ground cover for hiding is of top importance.
As we can tell most of these turtles/tortoises just like Darwin said adapt to their current habitats by changing little things between them. Like the box turtle that has webbed feet and can close their shell to protect from different predators, or the mud turtle that very dull shell color allows it to hide and be camouflaged from other predators. Then there is the Yellow-foot tortoise which has a large shell and rough rounded feet which allows it to move around on land without fear of hurting itself while walking around in different terrain. Before Darwin everyone spoke as animals being part of a large family that were all the same but as we can see by comparison with three different types of turtles that they all change to suit their environment and best help them survive it.
Another turtle that we saw in our class was the Central American Orante Wood turtle which is very bright in color. The Ornate Wood Turtle is a tribute to its beautiful and distinct markings that look as if they were painted by an artist. The turtle's high domed shell only adds to the dramatic effect. Both the shell and the head are light brown to olive, and it has bright red lines on the nose and face. Like most turtles, it is relatively long-lived and most will be about six or seven inches in length, although some may be slightly smaller or larger. Aside from being one of the most beautiful turtles the Ornate Wood Turtle is also one of the more personable. As a rule, it tends to be outgoing, curious and active. Many Ornate Wood Turtles will accept food from their keepers’ hands. Typically, the Ornate Wood In nature can be found in damp woodlands and scrublands.
As a matter of reference all these turtles might be closely related through the species but we can clearly see that they have developed traits that best suit them so if we were to interchange these turtles between their habitats we could see how the others might have a problem surviving. For example if we were to put the Yellow-foot tortoise in the typical mud turtle environment he would have a very tuff time getting along as his rough rounded feet would not support a swimming lifestyle. Or vice versa to add the mud turtle in a very dry climate with very little water it would nullify his use for webbed feet thus causing him to fall behind for that area and become the inferior species.
Darwin was way ahead of his time when he produced his theory which is why it took him about 20 years or so after he visited the Galapagos Islands to publish his collection of work. We continue to see as new species emerge ones that we are still not aware of in the fact that we will continue to adapt to our surrounding environments so that we may last and prove to be the superior species. The problem with all this is that as we grow we tend to forget about all other species of animals and start to take these lands for our own destroying the homes on hundreds of thousand animals. We must not forgot where we came from because if we forget out past we cannot see where we are going.
Many of us have different views on how man came to be, many of us think that the world was created in seven days and some of us think that we evolved. To understand how we came to be we must look at several different factors like how has the human species survived for so long dating back to pre-historic times. Then Darwin developed his theory of evolution which stated that all living things came from a simpler non-complex ancestor, which meant that we had evolved or mutated into our current forms. Now when most people think of mutation we think that it is a bad thing and that we are worse for it, but the reality of the situation is that Darwin believed that these mutations would help as adapt to our environment which meant the survival of our species. In our class we had the privilege of observing many different kinds of turtles and tortoises to see what Darwin was speaking of with the adaptation of each animal’s body to its natural environment.
To begin understanding all these different classes of turtles and tortoises we must understand what Darwin meant with his whole theory by breaking it down to its simplest form and seeing the change that he saw. First lets understand what he meant by Natural Selection which is the process by which animals who gain certain characteristics will survive because of the advantage of their certain mutations. More simply for example let us say there was a group of animals who had to travel great distances to obtain their food and over time one of those animals grew wings and learned to fly. Now this would significant because this animals would be able to cover greater distances at a much larger pace, and he would then pass on these traits to his offspring which would start to dominate the species that they grew off from thus wiping out the inferior species slowly but surely. Another example of this is the breeding of domestic animals which over time has come to create all the desired domestic species with all the traits one might desire in a domestic animal.
This process would be to great advantage to any species because it just ensures that a species must adapt to survive in this planet. You could even go as far to say that adaptation to one’s environment could be seen in today’s modern world. We all realize the rising cost of oil and it’s affect on our economic situation but did we ever wonder that right now we are adapting by creating cars that do not run solely on fossil fuels and at the same time addressing the rising concern of Global Warming and it’s affect on our climate change. Now it’s not as drastic as growing wings but it is a form of adaptation to our current environment and how we must live in it to ensure that this planet survives. We all adapt to our environment by wearing more clothes if it’s cold or less if it’s hot. This is something that we all do inherently because we know in our minds that we must do so to ensure that we all survive which is a form of self preservation.
We all might ask how Darwin came up with this theory of Natural Selection which came to be after his trip to the Galapagos Islands where he observed many different kinds of plant and animal species away from the mainland. At first he did not like the islands due to their appearance and did not realize the breakthrough he had found on the island for a couple of years after he left. He still believed that all animals were of the same inherent families, but it was a colleague of his by the name of John Gould who told him that the finches he had were not of the same family but a completely new family which he had discovered on the island on his excursion.
Darwin saw the difference in beak sizes between the finches which made them a perfect source of study for natural selection which was then confirmed some time after by later workers of the islands on their own mission to study this theory. Darwin also saw giant tortoises for the first time which we regarded as nothing more than an abundant food source on the island which they hunted and ate on the trip back to England. He also went back and left with a large load of tortoises which became extinct 10 years after he first got there due to the ships passing through and introduction of different animals that were starting to dominate the region which is why conservation of the islands grew to high importance.
Darwin then wrote a book with an accumulation of all that he had discovered from these islands called “On the Origin of Species” which was widely accepted by many scientist and seen as one of the most influential pieces of science ever written. The majority of people along with the church refuted these findings because at the time this was seen as something that was just not possible in any way but then confirmed and later accepted by many other. His ground breaking research led to the understanding of many different species on how they could have possibly turned into the forms of animals we see every day now.
In our class we were allowed to examine many different types of tortoises and turtles seeing the difference between them and making our own assumptions before we knew the true identity of every turtle/tortoise. This once again re-affirmed Darwin theory on how we all saw how all these different types of turtles belonged to the same species but had evolved to fit their surrounding environment to survive in it. Even as simple students we were able to depict the subtle difference in color, shape, size, texture, and aggressiveness between them. These findings were amazing to see because some turtles that looked identical ended up being very different and some turtles that didn’t even look alike had very common features due to them sharing the same type of environment.
Let me first start by explaining the difference between a turtle and a tortoise by discussing where they live. Turtles spend most of their time in or around water like oceans or freshwater because of how they are shaped. Their front feet are fins or usually webbed to allow them better movement in the water which is also accompanied by falter backs compared to tortoises. They like to mate and lay their eggs underwater or close shorelines and sometimes like to sun themselves on logs, rocks, or banks of rivers. They mostly eat plants, insects, and fish which are what is most abundant in their habitats causing them to be omnivorous.
Now let us speak about the tortoise which lives entirely above water only going to rivers to drink and clean themselves. They do not have fin or webbed feet like the turtle their feet are sometimes flat and rounded or have claws for digging which means they cannot swim and are prone to drowning if they fall in a river. They like to dig burrows which they climb inside of during hot sunny weather or when they like to sleep. They eat mostly shrubs and other plants which contain a lot of moisture making them mostly herbivores. Their shells are rounded domes so that they can pull in all their limbs in case of an attack by predators.
Now I will talk about the different types of turtles/tortoises that me and my classmates were allowed to examine. The first turtle I will speak about is the Florida Box turtle which has a hinged shell which allows it to completely close off its shell from outside intruders. They have a steep high dome rounded shell with a slightly hooked jaw and webbed feet. The males are typically larger than the females and have thicker and longer tails along with claws on their hind legs which are short, thick, and curved. In the summer season they are usually active only after rain showers or in the mornings and when it gets too hot they like to hide under decaying trees and in mud puddles or shady pools. Many do not know but box turtles may live past 100 years and are the more common pet turtle.
Next I will talk about the mud turtle which like many other turtles, mud turtles are omnivorous, and prefer damp, sandy, or muddy dwellings. Mud turtles rarely grow to sizes beyond 5 inches, and are therefore easy to keep indoors, or outdoors. Like most other turtles and reptiles, mud turtles love to bask in the sun's rays, and they can live to be over 50 years old, providing they can stay clear of predators. Mud turtles are known for their dull shell colors and relation to the smelly musk turtles. African and American mud turtles are very different and are not closely related. Their only similarities are in their choice of habitat, both preferring shallow, slow moving bodies of water with muddy bottoms, and having a dome shaped shell.
The next animal I will be speaking about is the Yellow-foot tortoise which is found in South America over a wide range from Bolivia through Brazil. This species is a rainforest species and as such its care requirements are more restrictive than those of the Red-foot. While the two species share habitats in some locations it appears that only the Red-foot tortoise will go out of the forest into the grasslands and brighter sunlight. The rainforest is typically seen as being a very stable environment, humidity is high, and temperature changes between night and days are fairly narrow. In addition to this, in rainforests the lighting is dim. It is these conditions that we seek to match when providing for Yellow-foots, providing a high humidity environment with night temperatures above 65 degrees F and day temperatures below 95 degrees F. Yellow-foots are less tolerant to very high temperatures than Red-foots, possibly because they have less tendency to wallow in shallow water and mud during times of extreme heat. They stress easily and providing a dim area such as large plants and ground cover for hiding is of top importance.
As we can tell most of these turtles/tortoises just like Darwin said adapt to their current habitats by changing little things between them. Like the box turtle that has webbed feet and can close their shell to protect from different predators, or the mud turtle that very dull shell color allows it to hide and be camouflaged from other predators. Then there is the Yellow-foot tortoise which has a large shell and rough rounded feet which allows it to move around on land without fear of hurting itself while walking around in different terrain. Before Darwin everyone spoke as animals being part of a large family that were all the same but as we can see by comparison with three different types of turtles that they all change to suit their environment and best help them survive it.
Another turtle that we saw in our class was the Central American Orante Wood turtle which is very bright in color. The Ornate Wood Turtle is a tribute to its beautiful and distinct markings that look as if they were painted by an artist. The turtle's high domed shell only adds to the dramatic effect. Both the shell and the head are light brown to olive, and it has bright red lines on the nose and face. Like most turtles, it is relatively long-lived and most will be about six or seven inches in length, although some may be slightly smaller or larger. Aside from being one of the most beautiful turtles the Ornate Wood Turtle is also one of the more personable. As a rule, it tends to be outgoing, curious and active. Many Ornate Wood Turtles will accept food from their keepers’ hands. Typically, the Ornate Wood In nature can be found in damp woodlands and scrublands.
As a matter of reference all these turtles might be closely related through the species but we can clearly see that they have developed traits that best suit them so if we were to interchange these turtles between their habitats we could see how the others might have a problem surviving. For example if we were to put the Yellow-foot tortoise in the typical mud turtle environment he would have a very tuff time getting along as his rough rounded feet would not support a swimming lifestyle. Or vice versa to add the mud turtle in a very dry climate with very little water it would nullify his use for webbed feet thus causing him to fall behind for that area and become the inferior species.
Darwin was way ahead of his time when he produced his theory which is why it took him about 20 years or so after he visited the Galapagos Islands to publish his collection of work. We continue to see as new species emerge ones that we are still not aware of in the fact that we will continue to adapt to our surrounding environments so that we may last and prove to be the superior species. The problem with all this is that as we grow we tend to forget about all other species of animals and start to take these lands for our own destroying the homes on hundreds of thousand animals. We must not forgot where we came from because if we forget out past we cannot see where we are going.
“Tortoises or land turtles are land-dwelling reptiles of the family of Testudinidae, order Testudines. Like their marine cousins, the sea turtles, tortoises are shielded from predators by a shell. The top part of the shell is the carapace, the underside is the plastron, and the two are connected by the bridge. The tortoise has both an endoskeleton and an exoskeleton. Tortoises can vary in size from a few centimeters to two meters. Tortoises tend to be diurnal animals with tendencies to be crepuscular depending on the ambient temperatures. They are generally reclusive animals. The biggest operational difference between tortoises and turtles is that tortoises are unable to swim; indeed, they cannot float, whereas turtles can” (www.answers.yahoo.com/question/index?qid=20080409144910AAbkGR8&show=7, retrieved 4/19/2008).
“The Galápagos tortoise (or Galápagos giant tortoise), is the largest living tortoise, endemic to nine islands of the Galápagos archipelago. Adults of large subspecies can weigh over 300 kilograms (660lb) and measure 1.2 meters (4 ft) long. Although the maximum life expectancy of a wild tortoise is unknown, the average life expectancy is estimated to be 150-200 years. The Galápagos tortoises have very large shells (carapace) made of bone which is an integral part of the skeleton. The bony plates of the shell are fused with the ribs and other bones to form a rigid protective structure. When a tortoise feels threatened it can withdraw its head, neck and forelimbs into its shell for protection, presenting a thick shield to a would-be predator. The legs have hard scales that provide an effective armor when withdrawn” (www.wikipedia.org/wiki/Gal%C3%A1pagos_tortoise, retrieved 4/19/2008).
“In the 19th century, Charles Darwin, a biologist from England, set off on the ship HMS Beagle to investigate species of the Galapagos Islands. After spending time on the islands, he soon developed a theory that would contradict the creation of man and imply that all species derived from common ancestors through a process called natural selection. Natural selection is considered to be the biggest factor resulting in the diversity of species and their genomes. One of the prime motives for all species is to reproduce and survive, passing on the genetic information of the species from generation to generation. When species do this they tend to produce more offspring than the environment can support. The lack of resources to nourish these individuals places pressure on the size of the species population, and the lack of resources means increased competition and as a consequence, some organisms will not survive. The organisms that die as a consequence of this competition are not totally randomly. Darwin found that those organisms more suited to their environment were more likely to survive. This resulted in the well known phrase ‘survival of the fittest’, where the organisms most suited to their environment had more chance of survival if the species falls upon hard times. Those organisms who are better suited to their environment exhibit desirable characteristics, which is a consequence of their genome being more suitable to begin with. This 'weeding out' of less suited organisms and the reward of survival to those better suited led Darwin to deduce that organisms had evolved over time, where the most desirable characteristics of a species are favored and those organisms who exhibit them survive to pass their genes on. As a consequence of this, a changing environment would mean different characteristics would be favorable in a changing environment. Darwin believed that organisms had 'evolved' to suit their environments, and occupy an ecological niche where they would be best suited to their environment and therefore have the best chance of survival. As the above indicates, those alleles of a species that are favored in the environment will become more frequent in the genomes of the species, due to the organisms higher likeliness of surviving as part of the species at large” (http://www.msnbc.msn.com/id/8727984/-storyContinued, retrieved 4/20/2008).
8 tortoises/turtles:
1. The first one had a dark brown shell with yellow, beige lines in a pattern and a scaly skin for protection.
2. The second one had “scary” hands and a very round shell. It was dark with a few light spots and it had a hairy tail. It had red spots on the legs and tail. The sides of the shell were very closed, hard and protected. The legs were thick, and it had big eyes that were close together.
3. It had a multicolored shell and skin. It was skinny and long and had a small head. The shell covered more of the body on the sides than the others. It didn’t have a hinge. The shell was not round and the wings were pointing up at the tip/end. The eyes were bulging out.
4. It had a very light greenish/yellowish skin and small front legs. The shell was light brown with beige lines. The mouth was narrow with a protruding top lip. The nose was pointy and smaller than the others. It had a hinge on the inside of the shell so that it can lose the whole shell.
5. It had red eyes and reddish, scaly skin. The shell was brown and beige and the legs were thicker and longer than the others. It had a longer neck, a wider mouth, a different color of skin, and a bigger tail than the others as well.
6. It had a beige shell with black spots and scaly skin. It looked much like number 1 only it had longer nails and a pointy, straight face.
7. This one was the smallest one in the group. I also think it was the only turtle because it had webbed feet so it can probably swim. The skin was green with black dots on it. The mouth opened wide. The skin was also softer than the others, especially underneath.
8. This one was the biggest one out of all of them. It had large legs and a hard, round shell. It had a brownish greenish shell and a beige multi textured skin. It also had large circular scales on the legs.
The turtle has an advantage because it can go into the water, swim and float. But there are a lot of predators in the water as well as on land. The biggest one would be the most intimidating one, so I assume it has fewer predators than the others. One of them could hide completely in their shell so it’s impossible for predators to get to them. That is a great capability to help the survival of a tortoise. A big disadvantage for tortoises with the reddish color is that because of the reddish coloring it will stick out more in nature for predators to see more easily.
I don’t know which one of them would be the fittest to survive. I think they all have a great chance seeing that turtles and tortoises can adapt easily and go for a long time without food, and seeing that they have been around for more than 250 million years. Their biggest enemy is us, humans. We are the reason why some of them are facing extinction. If we start taking care of our own shit, like global warming, pollution etc. they will all have a great chance of survival! So I guess it’s up to us.
References
http://www.msnbc.msn.com/id/8727984/-storyContinued
http://www.msnbc.msn.com/id/8727984/-storyContinued=7
http://www.wikipedia.org/wiki/Gal%C3%A1pagostortoise
Kelly Haran
During class last week, we were given the privilege of getting to look at all different types of turtles and tortoises. To be completely honest with you, before this class, I really never knew the difference between the two. What I found most interesting is the fact that a tortoise is a kind of turtle, but not all turtles are tortoises. The different types we looked at were: The Box Turtle, The Red Foot Tortoise, The Central American Ornate Wood Turtle, The Russian Tortoise, The Mud Turtle, and The Yellow Foot Tortoise.
Turtles mostly live in or near the water and are able to hold their breath underwater. They are able to live in freshwater, the ocean, or even ponds. On the other hand, tortoises live primarily in places that are built for storing their own water supply and walking on regular ground. Turtles have flatter shells than tortoises and lay eggs underwater or on the shore. They are more omnivorous than tortoises and eat fish, insects, and plants. Tortoises live on land and only go in water to clean themselves or for a drink. If they are not careful, they could possibly drown from not having good swimming skills. They have claws that help them to dig burrows to sleep in or to escape hot weather. They are often herbivorous eating things such as plants and cactus, which have a lot of moisture.
The first one was the Box Turtle. It’s called this for the reason that its shell actually closes. This type has a domed shell, which actually has a hinge at the bottom. This characteristic allows the animal to close its shell completely to escape predators.They have a very flexible shell. This particular turtle is native to Florida. The Box Turtle can commonly live up to twenty years, while some times they can live up to 40 or even 50 years. This Box Turtle is a female and you can tell because the shell is more plain. The shell has a grassy bottom and top that would definitely help them when trying to blend in with the environment. Today the Box Turtle has become very popular as pets, a certain amount of them need to be left in their natural habitats. Taking these turtles into our homes and keeping them as personal pets, can often have very serious effects on our wildlife population.
The second one was the Red Foot Tortoise. This type is actually a South American Red Foot and is primarily found in Colombia. They live in open grasslands but they actually prefer to live in humid forest areas. They have a high dome, rounded, dark shell. They have a red coloring on their legs and no beak. They only eat grass. They can live up to 50 years and males tend to be larger than females. The Red Foot actually has an even larger cousin who I will also speak about in a little known as the Yellow Foot Tortoise.
The third one was the Central American Ornate Wood Turtle. As the name would suggest, they are native to Central America. This turtle is very colorful and lives in shallow waters. This particular one is female and you can tell by its tail. You can distinguish males from females by the thicker tail size. It has a long neck and a dark outer shell. It also has red and white coloring on the sides of its shell. This type spends most of its time on land. It eats both plants and animals, such as fish, fruit, grass, insects, wildflowers, and worms. Ornate Wood Turtles are very important to us humans because they actually feed on many insects.
The fourth one was also the Box Turtle. This particular one is a sub-species and only grown in Texas. The coloring of it is good for blending in with tall grass. It also has front claws and a long neck. Its beak is helpful for picking food and its high-rounded shell helps them to blend in almost as a rock in the environment. Its yellow head indicates that it is a male. The Box Turtle can commonly live up to twenty years, while some times they can live up to 40 or even 50 years. This Box Turtle is a female and you can tell because the shell is much more plain. The shell has a grassy bottom and top that would definitely help them when trying to blend in with the environment. Today the Box Turtle has become very popular as pets, a certain amount of them need to be left in their natural habitats. Taking these turtles into our homes and keeping them as personal pets, can often have very serious effects on our wildlife population. It’s very important because these specific sub-species are only grown in Texas, its imperative that they aren’t taken from their true home.
The fifth one is also a Box Turtle. This particular one is native to Florida. It has very cool red eyes and is very colorful. It’s red and yellow coloring indicates it is a male. This turtle has big claws for digging and a long neck. His shell is pretty flat and was rather feisty. The turtle kept trying to bite me as I picked it up to get more interesting characteristics about him. The Box Turtle can commonly live up to twenty years, while some times they can live up to 40 or even 50 years. This Box Turtle is a female and you can tell because the shell is more plain. The shell has a grassy bottom and top that would definitely help them when trying to blend in with the environment. Today the Box Turtle has become very popular as pets, a certain amount of them need to be left in their natural habitats. Taking these turtles into our homes and keeping them as personal pets, can often have very serious effects on our wildlife population.
The sixth one I looked at was the Russian Tortoise. This is a land turtle and was a male. It had very sharp claws and a big, long tail. Its mouth was a big sized beak and had black spots all over its shell. The Russian Tortoise also is a vegetarian. They range from about 6-10 inches. The females actually grow larger than the males. Males often have a longer tail and are often tucked to the side. Females tend to have more flared marks on their shells, while males do not have them. The color of these Russian Tortoises typically vary but the shell is normally a brown or blackish color with a little bit of yellow. The body of the tortoise is a yellowish-brown.
The seventh one was the cutest baby turtle ever. It was the Mud Turtle. It’s from North America and is actually the only real turtle that was brought to class. It eats fish and has a high-arched shell. It has green skin and a very point nose. It’s not flexible at all. They have a dull colored shell. They prefer to live in damp, sandy or muddy dwellings. It is very unusual for Mud Turtles to go in any type of water, but occasionally they will dip into swampy areas. Although they are primarily carnivores, they eat basically anything. Common meals for them will consist of anything they can catch such as: crustaceans, fish, insects, tadpoles, worms, and even tiny berries. Mud turtles really only grow up to about 5 inches and sometimes live up to 50 years old.
The eighth one was a Yellow Foot Tortoise. Like I said earlier, this is actually the cousin of the Red Foot Tortoise. It has claws but no beak. It was very slow at moving and had a very woody-looking shell. It lives in the forests and this particular one is a female.It has yellow scales on its head and the top of the shell is black with a small, yellow area around its body. There is often disagreements about where this type of is mostly found, but for the most part the yellow foot tortoise lives in grasslands. They are found in the open habitat of Surinam. While it’s cousin the Red Foot has actually begun to move out of the forests, and into grasslands, the Yellow Foot as remained in the forest.
Darwin’s Theory of evolution really changed our thought process. What Charles Darwin actually did was bring a new thought to an old philosophy. He brought up the topic of something called natural selection. This process occurs when favorable traits become more common in organisms and unfavorable traits become less common. It’s like the picking and choosing of what traits you want to stick around. In this process, the preservation of a functional advantage helps to keep a specific species alive in the wild. It helps to eliminate undesirable traits over time.
Darwin’s Theory has a lot to do with the survival and the well being of these turtles and tortoises. After looking at these creatures, I realized how their traits definitely help to preserve their well-being. Their personal characteristics possibly determine how long they will live. For instance, the color of their shell could help them blend in with the grass which would keep them alive longer. Also, if they have a hinged-shell, they are more likely to hide out in their shell to protect them from possible predators. Their front claws can help them to dig into sand or dirt.
Darwin’s Theory applied to all of these turtles and tortoises. Because of natural selection, they are able to have qualities that will help them survive longer. They are able to sustain a greater life because of things such as color, location, and size. I really enjoyed being able to participate with these creatures hands on and I feel that by doing this observation, I learned a lot. I really only knew basics about turtles and tortoises and now I feel confident saying I feel much more educated in this specific areas. I thought all of them were very beautiful looking but my all time favorite was the Mud Turtle!
Works Cited
http://42explore.com/turtle.htm
http://www.britannica.com/eb/article-9054127/mud-turtle
http://en.wikipedia.org/wiki/Tortoise
http://en.wikipedia.org/wiki/Turtle
Evolution
Evolution is merely change, and so is all pervasive; galaxies, languages, and political systems all evolve. Biological evolution is changes in the properties of populations that are considered evolutionary are those that are inheritable via the genetic material from one generation to the next.
Biological evolution is a powerful and important process. It is a process which, over billions of years, gradually selects the organisms that are better adapted to their environment, and in this way takes advantage of random mutations to continuously change life and make all living organisms in existence be the way they are. Evolution is not a finished event, of which we, humans, are the final product. Rather, it is a continuing process which has been changing and forming life on earth for billions of years and continues to do so for as long as organisms are being born, dying, and competing for what they need to survive and reproduce.
The theory of Evolution states that:
1) All life forms (species) have developed from other species.
2) All living things are related to one another to varying degrees through common descent.
3) All life on earth has a common origin. In other words, that in the distant past, there once existed an original life form and that this line form gave rise to all subsequent life forms.
4) The process by which one species evolves into another involves random heritable genetic mutations, some of which are more likely to spread and persist in a gene pool than others.
In theory, evolution is believed to have taken billions and billions of years, which has frequently conflicted with the religious beliefs of many. The idea of evolution was first recorded on paper by Charles Darwin in his 1859 book The Origin of Species. He was only 22 years old when se set out in 1831 on his epic five year, around the world voyage aboard the H.M.S. Beagle. It was to be the adventure of a lifetime, and would lead to insights that would revolutionize the field of biology. Initially an indifferent student, Darwin had found inspiring professors in his last year of college. One of them helped him get a position as an unpaid naturalist on board the Beagle. Darwin turned out to be a perceptive observer, an avid collector of specimens, and an extraordinary scientist.
On the Origin of Species, was finally made public in 1859, it was both strongly criticized and highly praised. Although Darwin was careful not to question the existence of a Divine Creator, many people interpreted his theory of gradual change in nature as a challenge to their faith. Others took his theory of survival of the fittest much further than Darwin intended, applying it to human societies, economics, and politics.
One of the greatest difficulties for the theory of evolution was that little was known in Darwin’s day of the mechanisms of heredity. No one could explain how genetic variation could arise in a natural population, or how inheritable traits could be sorted and recombined in offspring. It took nearly another century before biologists could use their understanding of molecular genetics to put together a modern synthesis of evolution that clarifies these details.
An overwhelming majority of biologists now consider the theory of evolution through natural selection to be the cornerstone of their science. The theory explains how the characteristics of organisms have arisen from individual molecules, to cellular structures, to tissues and organs, to complex behaviors and population traits.
Darwin’s theory of evolution is the widely held notion that all life is related and has descended from a common ancestor. The birds and the bananas, the fishes and the flowers, all related. Darwin’s general theory presumes the development of life from non-life and stresses a purely naturalistic descent with modification. That is, complex creatures evolve from more simplistic ancestor naturally over time. While Darwin’s theory of evolution is a relatively young archetype, the evolutionary worldview itself is as old as antiquity. Ancient Greek Philosophers such as Anaximander postulated the development of life from non-life and the evolutionary descent of man from animal. Charle Darwin simply brought something new to the old philosophy a plausible mechanism called natural selection. Natural selection acts to preserve and accumulate minor advantageous genetic mutations.
Evolution involves two interrelated phenomena:
1) Adaptation
Over the course of time, species modify their phenotypes in ways that permit them to succeed in their environment.
2) Speciation
Over the course of time, the number of species multiplies; that is, a single species can give rise to two or more descendant species. In fact, Darwin maintained that all species are related; that is, any two species on earth today have shared a common ancestor at some point in their history.
The adaptive strategy of an organism is not the only thing which creates biological changes. A species is always within a constant state of flux, as is the environment where they live. The obvious question is, is an organism able to adapt completely to its environment, and the honest answer is no. The environment of earth is in constant state of flux, but changes in an environment generally occur within time spans of tens of thousands of years, save for a few examples where changes occurred in an interval of a 100 or 200 year time span.
Oscar Martinez
Luke Ford
Environmental Studies
April 23, 2008
Darwin’s Theory of Evolution Applied
Darwin’s theory of evolution is a widely taught and known theory about the natural progression of life. It says that organisms naturally evolve; when ever a organism is born with a new attribute it has the potential to become the next step in the evolutionary chain for that species. If its new attribute helps the organism to survive better then its peers then it will do better and mate more frequently. Through time the old version of the species without the beneficial attribute will be out competed and die out. Darwin originally studied animals on the fascinating Galapagos but this theory can be applied to any species anywhere around the world. In this essay we will be discussing turtles and tortoises, we will discus how their evolved attributes help them to survive in their natural environments.
Specimen number one is a Box Turtle native to Florida. Its main attribute is a flexible underbelly. It has biological hinges on the bottom of its shell that allow it to close itself completely in its shell giving it a measure of protection over other turtles that cannot seal themselves in their shells. The camouflage on its top and bottom are uniform making it equally hard to see on the ground and in the water from both above and below the water. Finally it has a shark beak that can be used for both predatory and defensive needs.
Specimen two is a red footed turtle. It has proficient digging claws that no doubt are very useful when it comes to digging a nest on the bank of a lake or pond. It also has a sharp beak that it can hunt and defend with. It has a uniform shaped shell on its top and bottom; this attribute may come in handy should the turtle flip over because the lack of a lip around the joint between top and bottom would make it easier to turn itself right side up. Finally its shell is a dark muddy brown that would make it nearly impossible to see in dark muddy water or on a muddy bank.
Specimen three is a Central American Ornate Wood Turtle. It has a long neck that helps the organism to turn itself right side up if it flips over; also it can reach food higher up off the ground. It also has a dark shell the helps it camouflage in muddy water or on a muddy bank. It has digging claws that help it dig a nest during mating season. It also has a red stripe around the edge of its shell; in nature bright colors like red, orange, and yellow are usually warning signs to stay away. This organism has capitalized on the natural warning system.
Specimen four is a Box Turtle native to Texas. It has color patterns on its shell that closely resemble dry grass like you might find in arid Texas so it is well camouflaged. It has long sharp claws that serve not only as a viable defense from predators but also they help with moving on land and digging a nest. It has a long neck that might help it reach food higher up off the ground, or it can turn itself over if it flips. It has a shark beak that can be used for defense or predation.
Specimen number five is also a Box turtle native to Florida. This species has red eyes that are very intimidating and might be used to ward off predators. It has a round shell that might make it hard to grip with a predator’s mouth. It also has a long neck that might be used to obtain food from higher sources.
Specimen six is a Russian Tortoise. It has a dark shell that serves to camouflage it from predators. It also has large digging claws that not only help the organism to dig but also to walk on land as tortoises do. It has a beck for hunting small prey and defense. It has an extremely long tail that may be used to maneuver itself during mating.
Specimen seven is a Mud Turtle. It has a dark shell that helps it camouflage in its favored environment which the name suggests is mud. Its shell is peculiar in that is has a raised spine from the head to the tail; it also has a pounced lip at the junction of the top and the bottom of the shell. Both of these features make it difficult for a predator to grip the turtle in its mouth. It has webbed feet that no doubt are used to propel the organism through its watery environment.
Specimen eight is a Yellow Foot Tortoise. It has no webs; rather it has large digging claws for digging and moving on land. This species grows very large which means that with its strong shell and large size it is safe from most predators, one because it would be impossible for all but the biggest predators to eat but also because it is a convincing rock when it is still.
All of the attributes of the organisms listed above have been gained through evolution. It is conceivable that all of these species evolved from a common ancestor. They each developed qualities that helped them to survive in their native land. A species may gain a certain shaped shell to help protect against a certain type of predator in the area in which they exist. A longer neck will help a species acquire food in areas where food on the ground is scarce and they need to find other sources of sustenance. A species may copy other successful organisms like the Central American Ornate Wood Turtle who has a red stripe on its shell that predators associate with poison or some other equally painful or displeasing deterrent. In Conclusion, Darwin’s theory of evolution explains why different species if turtle and tortoise have different attributes that help them life in their natural environment.
Luke Ford
Environmental Studies
April 23, 2008
Darwin’s Theory of Evolution Applied
Darwin’s theory of evolution is a widely taught and known theory about the natural progression of life. It says that organisms naturally evolve; when ever a organism is born with a new attribute it has the potential to become the next step in the evolutionary chain for that species. If its new attribute helps the organism to survive better then its peers then it will do better and mate more frequently. Through time the old version of the species without the beneficial attribute will be out competed and die out. Darwin originally studied animals on the fascinating Galapagos but this theory can be applied to any species anywhere around the world. In this essay we will be discussing turtles and tortoises, we will discus how their evolved attributes help them to survive in their natural environments.
Specimen number one is a Box Turtle native to Florida. Its main attribute is a flexible underbelly. It has biological hinges on the bottom of its shell that allow it to close itself completely in its shell giving it a measure of protection over other turtles that cannot seal themselves in their shells. The camouflage on its top and bottom are uniform making it equally hard to see on the ground and in the water from both above and below the water. Finally it has a shark beak that can be used for both predatory and defensive needs.
Specimen two is a red footed turtle. It has proficient digging claws that no doubt are very useful when it comes to digging a nest on the bank of a lake or pond. It also has a sharp beak that it can hunt and defend with. It has a uniform shaped shell on its top and bottom; this attribute may come in handy should the turtle flip over because the lack of a lip around the joint between top and bottom would make it easier to turn itself right side up. Finally its shell is a dark muddy brown that would make it nearly impossible to see in dark muddy water or on a muddy bank.
Specimen three is a Central American Ornate Wood Turtle. It has a long neck that helps the organism to turn itself right side up if it flips over; also it can reach food higher up off the ground. It also has a dark shell the helps it camouflage in muddy water or on a muddy bank. It has digging claws that help it dig a nest during mating season. It also has a red stripe around the edge of its shell; in nature bright colors like red, orange, and yellow are usually warning signs to stay away. This organism has capitalized on the natural warning system.
Specimen four is a Box Turtle native to Texas. It has color patterns on its shell that closely resemble dry grass like you might find in arid Texas so it is well camouflaged. It has long sharp claws that serve not only as a viable defense from predators but also they help with moving on land and digging a nest. It has a long neck that might help it reach food higher up off the ground, or it can turn itself over if it flips. It has a shark beak that can be used for defense or predation.
Specimen number five is also a Box turtle native to Florida. This species has red eyes that are very intimidating and might be used to ward off predators. It has a round shell that might make it hard to grip with a predator’s mouth. It also has a long neck that might be used to obtain food from higher sources.
Specimen six is a Russian Tortoise. It has a dark shell that serves to camouflage it from predators. It also has large digging claws that not only help the organism to dig but also to walk on land as tortoises do. It has a beck for hunting small prey and defense. It has an extremely long tail that may be used to maneuver itself during mating.
Specimen seven is a Mud Turtle. It has a dark shell that helps it camouflage in its favored environment which the name suggests is mud. Its shell is peculiar in that is has a raised spine from the head to the tail; it also has a pounced lip at the junction of the top and the bottom of the shell. Both of these features make it difficult for a predator to grip the turtle in its mouth. It has webbed feet that no doubt are used to propel the organism through its watery environment.
Specimen eight is a Yellow Foot Tortoise. It has no webs; rather it has large digging claws for digging and moving on land. This species grows very large which means that with its strong shell and large size it is safe from most predators, one because it would be impossible for all but the biggest predators to eat but also because it is a convincing rock when it is still.
All of the attributes of the organisms listed above have been gained through evolution. It is conceivable that all of these species evolved from a common ancestor. They each developed qualities that helped them to survive in their native land. A species may gain a certain shaped shell to help protect against a certain type of predator in the area in which they exist. A longer neck will help a species acquire food in areas where food on the ground is scarce and they need to find other sources of sustenance. A species may copy other successful organisms like the Central American Ornate Wood Turtle who has a red stripe on its shell that predators associate with poison or some other equally painful or displeasing deterrent. In Conclusion, Darwin’s theory of evolution explains why different species if turtle and tortoise have different attributes that help them life in their natural environment.
INTRODUCTION
The purpose of this paper is to take a look at the Theory of Evolution and to see if
it can be proven that plants and animals originated via the process of natural selection
or survival of the fittest. I am going to try and prove if this theory is factual or not. I am
going to look at eight different turtles and tortoises that were examined in the class to see
if this theory holds true. These reptiles are owned and raised by our professor.
First we have to look at the meaning of evolution. It is described as a “theory that
the various types of animals and plants have their origin in other pre-existing types and
that the distinguishable differences are due to modification of successive generations”.1
This definition was brought to light by the famous biologist Charles Darwin who was
observing the reptiles in the Galapagos islands in Ecaudor. After careful examination
of these reptiles including the turtle and tortoise, Darwin published his famous book in
1859 “On The Origin of the Species Of Natural Selection Or the Preservation Of the
Races in the Struggle for Life. “Darwin general theory presumes the development of
Life from non-life and stresses a purely naturalistic (undirected) ‘descent with modific-
ation’ that is complex creatures evolved from more simplistic ancestors naturally over
time. In a nutshell, as a random genetic code the beneficial mutation occurs within an
organism genetic code, the beneficial mutation are preserved because they aid in survival
a process known as natural selection. These beneficial mutation are passed on to the
1. www.allaboutscience.org/Darwins theory-of-evolution.htm. 4/22/2008
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next generation. Over time, beneficial mutation accumulate and the result is an entirely
different organism (not just a variation of the original, but an entirely different crea-
ture)”.2
From the above statement by Darwin we were able to make a brief summary of what
he was trying to say in laymans term. They are as follow:
1. Variation - In every population there is variation
2. Competition – all species have to compete for limited resources
3. Offspring – more offsprings are produced , so the species can survive
4. Genetics – genetic traits are passed on to offspring
5. Natural Selection – Most beneficial traits are more likely to survive
In the examination of the turtles in the class, we will have to use the five charact-
eristics mentioned above to judge them and see if we are able to draw the same
conclusions as Darwin. The eight turtles are from North America, Central American and
Russia. Each of the turtles are different with regards to colour,length of feet, webbing,
hinges on the back, colour of back, shapes of the back, shapes of mouth, length of tail,
shapes of their foot to conform to habitat, colour of their eyes. Three of the turtles are
of the same species but they are all different.
Variation: As stated above all the turtles vary in different ways. In looking at plants
and animals in the environment we observed that every species has some sort of
variation. At times these variation will tell how unique plants and animals are
2. “Darwin theory of evolution com. 4/21/2008
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To understand why variation takes place in all the species one has to look at how all
species originated. It is a proven fact that all animals originated as a result of the process
of sexual reproduction by male and female. All changes that cause variation in the
species come from the exchange of genes. “ Variation comes from mutation in genetic
material, migration between population (gene flow) and the reshuffling of genes through
sexual reproduction. Variation also comes from exchange of genes between different
species, for example, through horizontal gene transfer in bacteria and hybridization in
plants.”3
Competition: In the wild competition takes place among the species in that they have to
compete for limited resource such as food etc. It is not the fault of the turtles that scar-
city occurs. This has to do with external such as land erosion, deforestation, non replac-
ment of plants, urbanization and global warming. According to Earnest Mayr “Food
resources are limited but are relatively constant most of the time. It may be inferred in
such an environment there will be a struggle for survival among individuals”.4 Darwin
states that in the struggle for survival the fittest win out at the expense of their rival bec-
ause they succeed in adapting themselves best to their environment. 5
Offsprings: Turtles like all other animals and reptiles always give birth to a large number
of offsprings in order to ensure the survival of the species. This is done to make sure
that a few are able to survive and reproduce. This is a result of how the environment and
ecosystem is made up with regards to turtles and other animals. In order for survival
3. http//en wikepidia.org
4. Charles Darwin. Theory of evolution.
5. Ibid
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for survival each animals and reptiles live off each other as source of food in order to
exist. In order for the species to survive, it is not always the one who has extraordinary
traits and beneficial mutuations survive. In these circumstances species who have less
extraordinary traits are able to escape and survive.
Genetics: All the turtles in the population that were examined were blessed with identif-
iable traits from their parents , this is due to the transfer of genes during reproduction to
the offspring. These traits influence every aspect of the form of behavior and how these
turtles are able to adapt to their physical environment. This is the result of “mutation in
genes which can produce new or altered traits in individuals resulting in differences
between organism, but new traits also can come from the tansfer of genes
between population as in migration or between species in horizontal gene trans-
fer.”6
Natural Selection: Darwin came to the conclusion that organism with advantageous trait
were better able to survive and reproduce and transfer these traits to their offspring, while
others with rare traits were unable to survive or reproduce. In looking at the turtles, and
other living organisms, we can conclude that this is not true because advantageous and
rare traits will not influence survival of the species.
From examining the different facets of the evolution theory and those of the turtles,
we have come to the conclusion that Darwin theory of evolution is just a theory and is
not factual. The conclusions that Darwin arrived at were done by observation and what
he had learned in the field of biology, these theories cannot be validated in a laboratory.
6Charles Dawin Theory of Evolution wixipedia org
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Darwin suggested that life originated from non-life form. How can an organism be
created out of nothing. For a living organism to have life and be able to survive and
reproduce it has to be created by a supernatural being, and that being is God In genesis
1 verses 20-23 we see that all living things were created by God on the fifth day of
creation, verses 22 says “And God blessed them saying Be fruitful and multiply”7.
These three versus substantiate the fact that all living things were created by God.
Genesis 7:15-16 says those that went into Noahs ark before the flood were “two and
Two of all flesh, wherein is the breath of life. And they that went in male and female
of all flesh.”8 In the above statements we can prove that God created the earth and all
living things, and that they should reproduce after its own kind and inhabit the land. The
Bible is said to be the infallible word of God, therefore we can conclude that it is factual
and can stand up to the test of time, and also can hold up in any laboratory test. There-
fore we can conclude from the turtles we examined that some of what Darwin stated are
true, but most of it cannot be proved.
Darwin theory of evolution ruffled the minds of a lot of individuals, and his theory
will enable those who study the sciences to do a lot of thinking as they try to find where
the source of life came from. This theory has also helped in the field of genetic
engineering where emphasis is placed on artificial selection. 9
7The Holy Bible. Thomas Nelson Publishers. 1984 ., p1
8Ibid, p4
9http//en wixpedia.org
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April 23, 2008
Professor Jimenez
BIOL 1040-Environmental Studies
Evolution
Charles Robert Darwin
Charles Robert Darwin was born in England in February of 1809 at his family home. He was born into a wealthy family, father being a wealthy society doctor and financier. Darwin was born into a predominantly Unitarian family, but due to his mother’s beliefs, Darwin was baptized in the Anglican Church.
Later on in life, Darwin developed a keen sense of interest in natural history while studying medicine at Edinburgh University, as well as, studying theology at Cambridge University. He later embarked on a five year journey aboard the HMS Beagle at which he well established himself as a geologist. His theories and observations clearly supported that of Charles Lyell’s uniformitarian ideals. Through the publishing of his journal from the voyage, Darwin gained popularity and support from the general public, thus making him a famous and well respected author of that time.
Throughout the voyage, his curiosity towards the geographical distribution of wildlife, as well as, numerous fossils and artifacts he collected, led him to investigate and research the transmutation of species, thus creating his theory of natural selection. He proposed and presented evidence that all species have evolved throughout time from common ancestors through the process of natural selection. The fact that evolution has and still is occurring was widely accepted by the scientific community and general public during his lifetime. Throughout the 1930’s, natural selection was widely believed to be the initial cause of evolution and is now the cornerstone of modern evolutionary theory. More or less, Darwin’s theory is considered to be the groundwork for biology due to its ability to continually provide a logical explanation for the vast diversity of life on earth.
Journey aboard the HMS Beagle
As an unfinished naturalist, Darwin was fortunately given the opportunity to be a gentleman’s companion to Robert FitzRoy, captain of the HMS Beagle, on an expedition to chart the coastline of South America. The Beagle expedition took a grand total of five years, however two thirds of the voyage was spent on land. While on land Darwin carefully observed the species of wildlife that he encountered and he vigorously inspected and collected numerous remains of extinct wildlife, such as fossils. Throughout the journey, Darwin periodically couriered, back to London, numerous artifacts and letters showing his research, which were later the key to the creation of his theories and publications.
Prior to sailing out on the Beagle, FitzRoy gave Darwin the first edition to Charles Lyell’s Principles of Geology, which explained the causation of landforms over long periods of time. During their first stop ashore, Darwin witnessed a white band high in the volcanic cliffs made solely of baked coral fragments and shell. Later in the journey, Darwin observed tree fossils high in the Andes Mountains with remains of seashells nearby. This proved Lyell’s theory of how land rises or falls over long periods of time. Observing such incredible natural wonders, Darwin was convinced to write his first publishing on geology.
While the Beagle embarked through South America, Darwin found and excavated numerous fossils of large mammals alongside fossils of modern seashells. This proved to be evidence of a recent extinction of these large mammals. At the time, Darwin believed these mammals originated from Europe and Africa, but it was later pointed out to Darwin, that these mammals, though similar to mammals found on other continents, were exclusively found in only the Americas.
The second edition of Lyell’s book was later sent out to Darwin while he was still aboard the Beagle. This book argued against evolutionism and described the origins of diversity through different centers of creation. These ideals absolutely puzzled Darwin as his ideas went far beyond those of Lyell’s. In Argentina, Darwin discovered two different types of rhea that were found on different, but overlapping territories. While in the Galapagos Islands, Darwin collected numerous different birds and observed that mockingbirds differed depending on what island they were from. Darwin heard that locals were able to observe differences in tortoises all across the Galapagos and determine what island they were native to.
Darwin’s findings proved to show that species adapt to their environments and evolve overtime in order to help make these adaptations more sustainable to that species. Whether it be to ward off predators or to help the species find, locate, or kill food. Darwin’s theory proved the age old question of why there is a vast diversity amongst species of wildlife.
Environmental Studies Survey
We in our environmental studies class were asked to observe numerous species of turtles and tortoises. Similarly, like the natives in the Galapagos we observed the different traits and drew up our own conclusions as to why certain species have certain traits. There were six distinct different forms of turtles/tortoises we observed. Such species as:
Box Turtle (FL)
Box Turtle (TX)
Red Foot Turtle (South America)
Central American Ornate Wood Turtle (Central America)
Russian Tortoise (Asia)
Mud Turtle (North America)
Yellow Foot Tortoise (South America)
Box Turtle
One of the most distinct features we observed on the box turtle is its ability to hinge the bottom flap of its shell in order to completely close and lock itself into the shell. This is probably due to the box turtle living in a hostile territory, thus requiring the ability to protect itself in any way necessary. We fortunately had the opportunity to observe both a male box turtle, as well as, a female box turtle. The male box turtle had many key distinct features as opposed to its female counterparts. The males had a completely different hue; their colors were so much more bright and vibrant. Another distinct feature was the male box turtle’s red eyes. To go along with such aggressive colors, the male’s personality was much more aggressive and active compared to the females. The bottom of the male box turtle’s shell is slightly concaved. The reason for this is to help the turtle mount itself onto a female turtle while in the act of mating. Another key feature which may be a result of evolution is the sharp beak. The beak is used to effectively kill prey. The box turtle is an omnivorous creature, which will eat both small animals and vegetation.
Red Foot Tortoise
When observing this red foot tortoise we immediately recognized its flat belly and short claws, both being predominant signs of the female gender. The red foot tortoise originates in South America and mostly lives in open grassland regions. It got its name from the red scales that appear on its legs. We noticed that she has a short beak, which is most likely a product of evolution, due to the fact that all red foot tortoises eat are grass from the open grasslands in which it lives.
Central American Ornate Wood Turtle
Our particular ornate wood turtle is a female, due to the flat belly and short claws. The ornate wood turtle is mostly found in Costa Rica and are amphibians and live both under water and on dry land. It has a very rigid shell which is most likely its form of defense. The shell makes it difficult for predators, such as leopards, to grasp a hold on the ornate wood turtle’s shell. Also this particular species has a long neck. The reason for this is in order to help the turtle reach out and grab fish, which is its primary source of food.
Russian Tortoise
This particular Russian tortoise is most likely a male due to the concave belly and the prominent long claws. This tortoise’s main source of food is vegetation, therefore this species has evolved into having a sharp beak, most likely used to dig around for roots and through soil for vegetables. Also he was very agile on land which proved that he is solely a land bound tortoise. Also the Russian tortoise is found mostly in Asia, mostly the southern regions of Asia.
Mud Turtle
Out of all the species we studied, the mud turtle happened to be the only true sea turtle. It is found mostly in North America and lives mostly near greenery, such as seaweed. Due to the habitat it lives in, the turtle has evolved into having a green leaf like shell, most likely to camouflage itself in the greenery. Its main source of food is mostly fish and worms.
Yellow Foot Tortoise
Fortunately, the yellow foot tortoise that we observed was largest enough to really examine the numerous distinct features about it. We could clearly tell that it was a land based creature from its shear size and elephant like feet, which make it nearly impossible to swim underwater. Also this species lives in dense forest regions which helped the color of its shell to turn into a light greenish and brownish hue, which was most likely done in order for it to camouflage with moss and dense forest. This particular tortoise was a female due to its clearly distinct concaved bottom shell and its extremely short claws.
In conclusion, we were clearly able to situate ourselves into Darwin’s shoes, by observing distinct features and analyzing the process of evolution in order to determine why these changes were naturally made. This gives us insight not only into the past, but the future as well. What not only animals, but humans will encounter and endure through the natural process of evolution
Natural Selection
Altagracia Andre
Nova Southeastern University
Natural selection is the process by which favorable heritable traits become more common in successive generations of a population of reproducing organisms, and unfavorable heritable traits become less common (Ghiselin, 1973). The idea was introduced by Charles Darwin in his 1859 book The Origin of Species. Charles Robert Darwin was an English naturalist, well-known as a collector and geologist, who proposed and proved with scientific evidences that all species of life have evolved over time from common ancestors through the process of natural selection (Ghiselin, 1973). His theory provided an explanation for adaptation and speciation. In class, we were divided in groups and were brought eight turtles to analyze and try to guess in which environment they lived based on our observations.
The first turtle had five long claws, a short neck and was very fast. The second had a black shell with yellow pentagons, a short snout and once again was very agile one land. The following one consisted of a mixture of orange, yellow and brown similar to leopard pattern with five claws, a long neck. The fourth one was a bit different from the others with four claws and a very round shell. The subsequent one was more aggressive than the others with feisty red eyes. Its shell was of a brownish and yellowish color. The sixth in our opinion had to be a tortoise with its very agile and fast movement on the surface, a sharp pointy beak which might have been used for hunting and a shell pattern of black circle spots. The seventh one was smaller than the others, therefore a baby with sharp claws, a pointy shell, webbed feet, a rigid shell but a soft spot in the abdomen area. The last one was the biggest of all, also estimated to be the oldest. It had short claws, an oval shell with ridges at the bottom and short neck. At the end of our observations, our professor, revealed the different species and their specific environment.
The first, fourth and fifth were box turtles. The first and the fifth were from Florida, the fifth one a male and the other a female. In this specie, the male tend to be more colorful than the female. They are known to have a domed shell that is able to close and allow them to escape predators. They are omnivores and eats plants but are carnivores the first five to six years of their lives due to their needs in protein (Carr, 1983).The fourth turtle is a subspecies from Texas which the yellow with the brown helps it blend with the desert.
The second one was labeled as the red-footed tortoise native to South America. The red-footed tortoise, live in open grasslands and prefer humid forests areas. Being mostly a forest habitant, they possess a high domed narrow width shell facilitating getting between narrow openings of trees and vegetation in the rain forest (Ernst and Barbour, 1989). One can distinguish a male from the female by the tail. Males have a curved plastron and a much longer, pointed tail with the vent extending from the back of the shell. On the other hand, females have a flat plastron and a quite stubby tail with the vent within the edge of the shell. The red-footed tortoise can live up to 50 years (Carr, 1983).
The third one was referred to as the Central American Ornate Wood Turtle. They are native to Central America, as the name implies, and are generally found in damp woodlands and scrublands. They usually live near water and during dry weather will wade and swim in water. The Ornate Wood Turtle is terrestrial rather than aquatic, meaning it spends most of its time on land. In the wild, they feed on both plants and animals. They eat wildflowers, fruit, grasses, fish, worms, and insects. Ornate Wood Turtles are generally quite outgoing and curious hence the agility. Males can be distinguished from females by the thicker tail and concave plastron (Carr, 1983)
The next species was the Russian Tortoise. Russian tortoises are a small tortoise species, ranging from about 15 to 25 cm (6-10 inches) (Ernst and Barbour, 1989). Females tend to grow slightly larger than the males and males tend to have a longer tail that is generally tucked to the side. Their colors vary, but the shell is usually a ruddy brown or black, fading to yellow, and the body itself straw-yellow and brown (Carr, 1983). The Russian Tortoise consumes a variety of greens, grasses and vegetables. It is said that the Russian Tortoise is the first tortoise in space sent by the Soviet Union in 1968 (Ernst and Barbour, 1989). They hibernate during winter and estivate during the summer when temperatures are high. They are devoted burrowers and can dig large burrows that might be two meters (several feet) long which explains the long claws. They are herbivorous, and active grazers when the temperature is right, consuming a wide variety of weeds and grasses (Carr, 1983).
Turtle seven, was a personal favorite. It was out of all a “true” turtle with webbed feet and a baby. It is called the Mud Turtle. They are known for their rigid shells and prefer shallow, slow moving waters with muddy bottoms. They are primarily carnivorous and will eat almost anything they are able to catch such as fish, worms, insects and more (Ernst and Barbour, 1989).
The last one was actually cousin to the red-footed tortoise, the yellow-footed tortoise. It is originated from South America and the male is much lighter than the female. The tortoise was about ten years old but can live up to fifty years and prefers dense rainforests and tropical lowlands. The yellow-footed tortoise is a vegetarian (Carr, 1983).
Charles Darwin’s theory is based on careful observations. His theory implies that species are very fertile and have more offspring than can grow into adulthood (Ghiselin, 1973). He believed that most populations stay the same size with fairly small changes and food resources may be limited but become stable over time. No matter what, an implicit struggle for survivals applies (Ghiselin, 1973). Just as we were able to differentiate males from females because of the colors, shapes or sizes, Charles Darwin had a strong belief that in sexually reproducing species, often, two individuals are never identical (Ghiselin, 1973). The different variations in a species impact their ability to survive in a given environment such as the red-footed tortoise whose carapace facilitates movement. Much of these variations are inheritable. And as the theory of natural selection suggests, individuals less suited to a particular environment are less likely to survive and less likely to reproduce, while individuals more suited to the environment are more likely to survive and more likely to reproduce (Ghiselin, 1973). Those who survive pass their inheritable traits to the future generations.
This explanation of evolution by Charles Darwin and slowly effected process results in populations that adapt to the environment over time, and in due course, after endless generations, these variations accumulate to form new varieties, and eventually, new species, hence the different species and subspecies of turtles.
References
Carr, A. (1983). Handbook of Turtles, The Turtles of the United States, Canada, and Baja Calafornia. Ithaca, USA: Cornell University Press.
Ernst, C., & Barbour, R. W. (1989). Turtles of the World.Washington: Smithsonian Institution Press.
Ghiselin, M. T. (1973). Darwin and Evolutionary Psychology. Science Magazine, 179, Retrieved April 19, 2008, from http://www.sciencemag.org/cgi/reprint/179/4077/964
The evolution of turtles and tortoises.
The first turtles are believed to have existed over 200 million years ago in the Triassic period of the Messozoic era. The earliest known turtle, the Proganochelys, had many of the attirbutes of turtles these days, but through massive climate and other changes, the modern turtle differs much from this creature. For instance, this species did not have the ability to put its head into its shell. From this species to the turtles on our Earth today, there are massive changes and adaptations due to environmental changes caused naturally or by human modifications. As we discovered, recently in class, there are certain differences between turtles and tortoises. These are mainly because tortoises live on land and turtles live in the water. At first, they appear to be similar, but as one concentrates on the small details, there are many noticeable variations from species to species.In general, turtles live in or near the water and have adapted to swim by holding their breath underwater. Tortoises live primarily in arid regions, built for storing their own water supply and walking on sandy ground.In a biological respect, a tortoise is a kind of a turtle, but not all turtles are tortoises. Tortoises occupy their own taxonomic family, called testudinidae. All types of land and aquatic turtles come in a wide range of sizes, colors, and shapes. Sometimes the name "terrapin" refers to those animals that fall somewhere between a turtle and tortoise, because they live in swampy areas or begin life underwater and eventually move to dry land.
Turtles may live in freshwater, the ocean, or brackish ponds and marshland. Their front feet might be fins or merely webbed toes with streamlined back feet to help them swim. Turtles have flatter backs
than tortoises, and may spend all or part of their lives underwater. They mate and lay eggs underwater or on the shore. Tortoises live entirely above water, only wading into streams to clean
themselves or to drink. In fact, they could drown in deep or swift current. Their feet are hard, scaly, and nubby so it can crawl across sharp rocks and sand. Tortoises often have claws to dig burrows, which
they occupy during hot, sunny weather or during sleep. Tortoises are mostly herbivorous, eating cactus, shrubs, and other plants that have a lot of moisture. They rarely migrate. Their shell forms a rounded
dome, allowing the tortoise's limbs and head to withdraw for protection
The first difference is the paw and its formation. From our observations, we discovered that the turtles had webbed claws whereas the tortoises had longer claws. This was because the turtles, through
the evolution and time, found it easier to find food and a means of transportation, with the webbed paws. The tortoises on the other hand, found it easier to find their food, which consists of worms and bugs, mainly, in the ground. This is why they tend to have longer claws to facilitate the digging for food. We also noticed that they tend to be more agile and faster because they moved so quickly on the tables where we were observing them.
One tortoise in particular is called the Russian tortoise. It is also called four-toed tortoise or Russian box turtle. In its natural habitat the Russian tortoise is active only a few months of the year.
It comes out of hibernation in mid-March and actively forages and mates until mid-June. During the hottest parts of summer it aestvates. In Uzbekistan it hibernates from October through March. It is most active in the early morning and early evening, retreating to its burrows during the hottest portion of the day. It is characterized by its long claws and its agility. It is vegetarian which means it has a very flexible and long neck.
Another very popular turtle we had the fortune to see was the Box Turtle. these are the most common terrestrial turtle in the eastern United States. They are small to medium sized turtles, attaining a maximum length of about 8 inches and having a highly domed carapace. A key characteristic of box turtles is their hinged plastron (bottom of the shell) that can be shut completely to exclude predators. Although mud, musk, and blandings turtles also posses hinged shells, they cannot be closed completely. Superficially, box turtles resemble tortoises but they are actually more closely related to many aquatic turtles and belong to the same family as spotted, bog, chicken, map, and painted turtles, as well as sliders, cooters, and diamondback terrapins. Box turtles in the United States are divided into two species, the eastern box turtle (Terrapene carolina), which ranges from Texas throughout the southeast and north to Michigan and southern Massachusetts, and the western box turtle (Terrapene ornata), which ranges west of the Mississippi to Colorado and New Mexico. The western box turtle is superficially similar to the eastern box turtle but is typically smaller and has a shell marked with radiating yellow lines. There are an additional two species of box turtle that are endemic to restricted habitats in Mexico. One of these species (Terrapene coahuila) is almost totally aquatic.
Another very interesting turtle is the Central American Ornate Wood Turtle. This unique species is actually somewhere in between the turtle and the tortoise in its defining characteristics. It usually lives around damp woodlands and scrublands in Central America. This creature is omnivorous, which means it feeds on plants and animals. They are characterized by their attractive shell with its black and red colors. They are beneficial to human beings because they feed on many insects that often become pests. Unfortunately, people who want to sell them as pets are taking them out of their natural habitats. Central American Ornate Wood Turtles usually do not do well in captivity.
The examples above are only a few examples of some of the types of turtles and tortoises and their characteristics. These are just a few differences between turtles and tortoises through time and evolution. They have been able to adapt to the environment they are in today through natural selection and survival of the fittest.
Nicole Velez
Natacha Revelus
April 23, 2008
Bio. 1040
DARWIN’S FINCHES
Darwin was the first scientist to study the finches of the Galapagos Island, with that he made them famous. Darwin studied the different adaptive features and characteristics of the finches. No one finch was alike; they varied from island to island. This group of thirteen species is confined to the Galapagos Islands, except a single species found on Cocos Island, about 600 mi (960 km) northeast. Their special adaptations to various habitats were important evidence considered by Charles Darwin in formulating the theory of evolution; they are a striking example of adaptive radiation (Questia Encyclopedia, 2004).
Geographically isolated and without competition from similar species, these finches developed distinctive anatomy (particularly beak size and shape) and behaviors, with each species exploiting a unique feeding niche. The bill is adapted in the different species for different purposes, such as crushing seeds, pecking wood, and probing flowers for nectar. The woodpecker finch, Cactospiza pallida, an insect-eater, holds twigs and cactus spines in its beak to fish out larvae in tree cavities. Darwin proposed that the Galapagos finches evolved on the islands from a single species of finch from mainland South America. Modern methods of DNA (genetic) analysis have confirmed his insight. Darwin's finches are classified in three genera of the phylum Chordata, subphylum Vertebrata, class Aves, order Passeriformes, family Fringillidae, and subfamily Geospizinae (Questia Encyclopedia, 2004).
Darwin’s research was and still is a major break through in science. For a biologist they provide a wonderful opportunity to trace the evolutionary course of diversification and interpret it with ecologically relevant field observations. None of the species has become extinct as a result of human activities (Science Week, 2005).
The fact that these birds able to over come extinction due to human activity in their habitats is a great example of how evolution and natural selection is true and it really does work. Keep in mind that Darwin explored these islands back in 1835. Another great species to look at is us: the human population, we overcame it all. Although we now have advanced technology and medicine that helps to keep our species alive, we have come along way in the process of evolution.
Like the different turtles we observed in class, the finches have different sized beaks, talons, feathers, etc. These characteristics, when mating, were passed on to the offspring of the finches. There has been record of cross breeding/mating among two different finches from different islands, however, that seemed to just increase their potential because even the hybrid offspring survive quite well considering its circumstances. This is specifically when there is a rich supply of intermediate-sized seeds suitable for exploitation by birds of intermediate beak size. When they breed, they backcross to one of the parental species. Which one they breed with depends on the father, because when the time comes to choose a mate they do so largely on the basis of the song they learned from their fathers (Science Week, 2005).
Darwin and his theory of evolution and natural selection are very interesting. I believe that organism will forever be in this process because everyone wants to be the last one standing and able to reproduce and multiply to keep the genes alive.
Works Cited
http://www.questia.com/library/encyclopedia/darwins-finches.jsp#
http://scienceweek.com/2005/sw050930-1.htm
Yulissa Medina
Turtle and Tortoise
Eastern Box Turtle (Female): These turtle are land turtles with stumpy feet. A Key characteristic of box turtles is their hinged patron (button of shell) it can be shut completely too exclusive predators, it’s their defense mechanism (not all turtle have it) and their shell high-domed shell, the female box turtles have yellow stripes on the shell and it’s larger than the male. They resemble tortoise. The female box turtle has more coloration; it’s often more brightly colored than others which tell that it’s a female. It also has four claws on their feet. They live in the moist forested areas with plenty of underbrush. They venture in shallow water at the edge of the pond or streams and puddles. This turtle are found in many habitats, including thick woodlands, dry prairies and deserts. They are not water turtles but they need water to drink and stay cool for hot days. It is not unusual that they live up o thirty years or more. They are omnivorous; they have hook upper peak and they will eat almost anything, animals or plant, that’s if they can fit in their mouth but they are known as picky eaters, it doesn’t matter what food they provide the turtle with, it’s the surrounding that it’s in. If the turtles unhappy it just rather starve. Before purchasing the box turtle, the people have to be aware of these conditions.
Red foot tortoise: This tortoise is a land turtle that reaches up to a length of 10-14 inches and weight up to 30 pounds and they are medium size tortoise also known as the cherry head. They are found in the dry grassy to humid forests. The red foot tortoise are omnivores and they eat a wider range of foods than many others tortoises, such as leafy greens, vegetables and fruits. These tortoises are originated from Central and North South America as well as Central America. This tortoise is easy with sexing, they wobble their heads to impress the female and if the female is impressed she does it back. They are also Hardy, active and friendly. This tortoise needs about 12- 18 hours a day to receive Ultraviolet light because it produces vitamin D3 and that produces its calcium. It cannot be exposed to the cold or it will die. It needs between 85-90 degrees in the day time and 70 degrees in the night time.
Russian box tortoise: These tortoises are known by many names from Russian tortoise, steppe tortoise, and Afghanistan box turtle, four toe tortoise. This tortoise is found in Pakistan, Eastern Iran, and North West China. Most of these Russian tortoise are found in the pet trade are from the territory of Uzbekistan. Their habitats are dry open landscapes. The tortoise is mostly found in sand and clay deserts with spares grasses and bushes, but they are rarely found in dense grassy or cultivated fields. They make their homes in rock crevices. The Russian tortoises are a straw yellow color with black markings in the middle of each scute. They reach a maximum size of 10 inches in length; males are smaller than females. They have hooked upper beak. They feed on wide varieties of plants. They do not munch on grass but instead they prefer broad leafy plants. They will also eat flower, fruits, and berries. They can go for a long period of time without water, but when water is available they consume large amount. Russian tortoises are primarily herbivores; they eat plant and only plant to get their protein to maintain strong. This tortoise is similar to human; they can suffer from a bone disease called metabolic bone disease, its cause is by lack of calcium, Vitamin D or exposure to ultraviolet light.
Central America ornate wood turtle: They make their homes in damp wood land scrublands. They are found near the water and during dry weather, they swim in the water to cool off. These turtles are terrestrial they spend most of its a time on land than water. The wild turtle is omnivorous, they are picky eaters just like the female box turtle; it feeds on both plant and animals. They eat wildflower, fruits, grasses, fish, worms and insect. They are active creatures just like the Red foot turtle. This turtle is consider very beautiful because of its shell is red and black. The beautiful red and black shell is high-dome. They should be exposed to ultraviolet light at least 12 hours a day just like the Russian box tortoise.
Texas box Tortoise: Also known as the Gopherus berlandieri. This tortoise is a sub species. It’s being put in the endangered species list. This tortoise has yellow-orange eyes. It has columnar hind legs and stumpy like an elephant meaning that they are land turtle. They are primarily vegetarian like many others tortoise, they eat any plant that is available to them, they also have a high hooked peak to eat. Its preferred habitats are dry scrubs, sandy soils in open woods and grassland. It’s the smallest species, growing to only 8.5 inches. It’s illegal to collect this tortoise from the wild being endangered species. The only way you can have one if you adopt one from a known organization.
Florida box tortoise: You can find these tortoises in Florida Key West and is also called the Terrapene Carolina bauri. Their habitats are forest, scrubs areas, and marshes. The tortoise enjoys being more outside and more outside to spend their time soaking in the water. They seem to be very carnivorous even as adults. They have steep- margins, high domes shell with variables markings. They are larger than females not like many other tortoises. Their claws on their hind legs are short, thick and curved. They have thicker and longer tails, that’s when you know it’s a male. These tortoises are active after a long hot rainy day.
Galapagos Giant tortoise: Galapagos means tortoise in Spanish. It’s the largest living tortoise. They weight about 250-500 pounds and measures 6 feet from head to tail with stumpy feet; their shell is made out of bones. They don’t live for 30 -50 years, they live up to more than 100 years. They are the slowest animal going about.16 miles per hour. This giant tortoise are vegetarian, they spend most of their time feeding on plants and vegetables. Since their shell is domed and saddle backed it allows them to reach vegetation higher off grounds. It’s a herbivore, that eats prickly pears and fruits, leaves a and grass just like the Texas box tortoise. They have a tremendous water storage capacity, enabling them to survive the long arid season. This tortoise is found on the Galapagos Island just west of Ecuador in South America, because the island there was populated with 250,000 Galapagos turtle, Charles Darwin, an archipelago decided to name the Island like the tortoise. Unfortunately today, there is about 15,000 Galapagos giant tortoise in the island because of overhunting.
Darwin’s Theory of evolution:
Evolution is the process of change in the inherited traits of a population of organism from one generation to the other. Darwin’s theory is based on five key observations and inferences drawn from them. These observations and inferences have been summarized by the great biologist Ernst Mayr as follows:
1) Species have great fertility. They make more offspring than can grow to adulthood.
2) Populations remain roughly the same size, with modest fluctuations.
3) Food resources are limited, but are relatively constant most of the time.
From these three observations it may be inferred that in such an environment there will be a struggle for survival among individuals.
4) In sexually reproducing species, generally no two individuals are identical. Variation is rampant.
5) Much of this variation is heritable.
To Darwin theory it’s widely known that all life is related and has descended from a common ancestor, such as the birds and the bananas, the fishes and the flowers; to Darwin they are all related. He believes that complex creatures evolve from more simplistic ancestors naturally over time. He believes that the lives of the animals are changed depending on what conditions and environment we that human keep them in. People believe that Darwin’s theory is a slow process. Darwin wrote, "…Natural selection acts only by taking advantage of slight successive variations; she can never take a great and sudden leap, but must advance by short and sure, though slow steps."
Biology Work Cited Page
http://www.petuniversity.com/reptiles/turtles--tortoises/species/russian-tortoise/
http://www.centralpets.com/animals/reptiles/turtles/tur2639.html
http://www.hoglezoo.org/animals/view.php?id=69
http://www.thebigzoo.com/Animals/Galapagos_Giant_Tortoise.asp
http://www.darwins-theory-of-evolution.com/
http://www.spaceandmotion.com/Charles-Darwin-Theory-Evolution.htm
Brian Pestana
Charles Darwin was the author of the controversial book entitled On the Origin of Species by Means of Natural Selection. The main ideas that can be taken away from Darwin is that the natural selection is the driving force behind evolution, evolution does occur (contrary to religious beliefs), and phylogeny occurs through family roots. Phylogeny is the concept that all forms of life are related to one another genealogically. Darwin developed these ideas during a 5-year trip around the globe that would lead him to make his evolutionary discoveries. The H.M.S. Beagle was a British surveying vessel that sailed around the world on a mapping expedition in the 1830’s. Darwin was brought on as the ship’s naturalist. During his trip, he recorded information about sea life, plants and animals and even people he met on the voyage.
Evolution had been up for debate since the days of Aristotle. Aristotle believed that there were natural laws that told of how the world was created. This theory was an alternative to the myths and stories about the origin of the universe. During the mid-1800’s, a new debate spurred proposing that species were fixed and unchanging. This theory or concept was known as the Fixity of Species. According to the concept, every type of species was supposed to be an exact replica of its counterpart. It was believed that everything was built in one definitive way and there was no possibility for change.
During Darwin’s 5-year trip, he began to challenge the very notion that species were fixed or if they were prone to evolution. At the time, Darwin was considered the best naturalist in the world and was well-respected. This also helped him look at species differently than other researchers and thought it was important that all species should have uniqueness to them even though they were the same in some respects. Darwin’s evolution theory gave birth to the concept of natural selection. Natural selection is considered the cornerstone of modern biology and is very important to science, even today. Darwin explained that natural selection meant that all creatures occasionally mutate on an almost random basis. But, when a mutation actually made the creature superior to its predecessors, it was more likely to survive whatever conditions in which it was forced to live. Those without the mutation died off, leaving only those perfectly equipped to survive. It helped us to understand why differences exist within a species. It explains why one black-haired individual may have blue-eyes, while another one has brown eyes.
On September 16, 1835, Charles Darwin’s ship reached the Galapagos Islands. The crew docked there for five weeks and during this time, Darwin was able to study the different variety of species living on the chain of islands. He was in immediate awe of the differences in certain species from island to island and even said that if someone had spent time on the islands and saw a giant tortoise swimming off the side of a passing ship, they would immediately be able to tell which of the islands were home to the turtle. The variations between them were that dramatic. At the same time, Darwin noted that there were two different types of iguana that appeared to have evolved from the same species. Each one had characteristics that made it able to survive on that specific island. Natural selection meant that the iguana must have gone through a natural selection. Now, many may argue that Darwin could have stumbled on this theory anywhere. But, the Galapagos Islands are unique in the fact that there is an incredible variety of creatures that live there. Moreover, there are animal species that live on only one island and nowhere else in the world.
On that note, I would like to recommend that you visit www.pbs.org/wgbh/evolution. In this site, you will find several topics and videos on evolution. If you click on Darwin, go to The Origin of Species. That will take you to an amazing visual of how new species can evolve. It focuses on the Hawaiian fruit flies, Hawaiian Silverswords, Galapagos finches, tenrecs of Madagascar and the Lemurs of Madagascar.
Charles Darwin provided scientific evidence in the mid 1800’s about how different species evolved over time. Darwin's theory of evolution fundamentally changed the direction of future scientific thought, though it was built on a growing body of thought that began to question prior ideas about the natural world. The core of Darwin's theory is natural selection, a process that occurs over successive generations and is defined as the differential reproduction of genotypes. Darwin’s theory of natural selection was based on a process in which more desirable traits are systematically favored for reproduction. Natural selection focuses on the struggles of survival and reproduction. Natural selection requires heritable variation in a given trait, and differential survival and reproduction associated with possession of that trait. Only some of the organisms manage to survive, which allows for the more favorable traits to remain and the less favorable traits to disappear. Over time, through natural selection of the most desirable traits, the species begin to evolve. Evolution occurs as inherited traits change from one generation to the next. From 1831 to 1836 Darwin served as naturalist aboard the H.M.S. Beagle on a British science expedition around the world. In South America Darwin found fossils of extinct animals that were similar to modern species. On the Galapagos Islands in the Pacific Ocean he noticed many differences among plants and animals of the same general type as those in South America. The expedition visited places around the world, and Darwin studied plants and animals everywhere he went, collecting samples for study. On his return to England in 1836, Darwin tried to solve the puzzle of how species evolved. He proposed a theory of evolution occurring by the process of natural selection. The animals or plants best suited to their environment are more likely to survive and reproduce, passing on the characteristics that helped them survive to their offspring. Gradually, the species changes over time. In 1859 Darwin published 'On the Origin of Species by Means of Natural Selection'. This book was a success immediately and helped to promote Darwin’s new theory, though it was met with some criticism
In our class we studied several different types of turtles. These turtles were the red-footed tortoise, box turtle, russian tortoise, yellow-footed tortoise, and mud turtle. Turtles are often referred to as turtles and tortoises with the difference being, that turtle refers to all the species, where tortoise is defined as any land-dwelling species. The box turtle has a domed shell, with yellow lines, and 3 claws on each hand. Also box turtles have a hinged plastron that can be shut completely to hide from predators. Mud turtles tend to have dull shell colors to help them blend into their habitat of damp and muddy dwellings. These turtles sometimes go into swamps or ponds, but rarely go in the water. Their diet consists of fish, worms, and insects. The Russian tortoise has sharp long digging claws and a dark shell with black spots. The red-footed tortoise has a dark skin with red scales and its shell is a dark color with some yellow spots. Their shells are also high domed and narrow to allow the turtles to move about in narrow openings in the forests. And the red-footed has no beak, just a short snout to eat grass. The yellow-footed tortoise is a close relative to the red-footed. The yellow-footed has dark skin with yellow scales and a wood colored shell. It also has nails for digging on dry land. These tortoises have large and strong shells to protect it from predators.
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