Essay, Research Paper
Janzen, F.J. 1993. An Experimental Analysis of Natural Selection on Body Size of Hatchling Turtles. Ecology. 74: 332-341
Purpose:
The purpose of the experiment was to evaluate the effects of natural selection on hatchling turtle size. The author tested whether turtle hatchlings with bigger mass, body size, and plastron length would exhibit greater survivorship during movement from the nest to the water habitat.
Methods:
In conducting this experiment eggs from 17 different Chelydra serpentina clutches were collected from a National Wildlife Refuge area in Whiteside County, Illinois in the month of June 1990. The collected eggs were then incubated in two different environments. Either a dry -150kPa or a wet -950kPa environment, both environments maintained a temperature of 27.5.C. The containers were rehydrated twice weekly and the eggs rotated daily. Once the turtles hatched the date and body size of each individual was recorded. Approximately three weeks after hatching, the turtles were given a number and prepared for release and recapture.
The recapture process used a drift fence constructed of 50m of 15cm high aluminum flashing support, eighteen lidless, 25cm high plastic containers that were implanted into the sand at 3m intervals. The turtles were then arranged randomly in a line facing the nest and released at sunset, all were released together, since C. serpentina hatch synchronously. The collection pits were checked at sunrise, midday, and sunset. The experiment was terminated when two successive monitoring periods failed to produce a hatchling.
Findings:
The findings showed that the incubating conditions modified the phenotypes of hatchling snapping turtles. Those incubated in the wet environment were larger and took longer to hatch than those incubated in the dry environment. Nearly 60% of the (66 of 112) hatchlings were recaptured. The use of normal distribution to calculate bypass rate indicated that approximately two hatchlings probably missed the fence. There were no signs of predators around the collection pits, so the turtles were not attacked after reaching the drift fence. Survivorship was related to three different measures of body size and shape. Mean hatchling mass: wet environment was 8.63g with a standard deviation (SD)of 1.38 and the dry environment was 7.60g with a SD of 1.24. Mean plastron length: the wet environment was 20.60mm with a SD of 1.32 and in the dry environment 20.06mm with a SD of 1.35. The carapace length: wet environment 29.39mm a SD of 1.88 and dry environment 27.73mm with a SD of 1.78. The larger hatchlings had increased survivorship over the smaller hatchlings in all three of the variables. One calculated variable, PC1, the overall size and mass, was measured at 0.327. This accounts for almost 85% of variation in body size, which produces a change in body size of approximately one-third of a standard deviation. PC3, plastron length was measured at 0.282 and PC4, trade-off between hatchling mass and width was 0.162. PC3 and PC4 account for less than 5% of variation in body size. Other variables, I, opportunity for selection was 0.703 and h2, the heritability of body mass, was 0.72 + 0.34 for the wet environment and 0.17 + 0.28 for the dry environment.
Discussion:
The results of the experiment indicate that larger hatchlings may have a survival advantage over smaller hatchlings during migration from the nest to the aquatic habitat. The use of different water potentials permitted the analysis of survivorship among larger and smaller hatchling turtles. The moderate strength of natural selection and low heritability of hatchling size implies that evolution would not occur rapidly among C. serpentina.
In reviewing the presentation, I felt that the results section was very confusing I could not understand how the author analyzed each of the variables accounted for. Nor did the author ever describe what each principle component (PC) was, how it was measured, and what significance it played in determining the effects of natural selection on the hatchlings. The author did however address the issue of predation upon the hatchlings. The author explained that the use of clay or model hatchlings might give us a better understanding of how/if hatchling size has an effect on predation. Finally, the methods section was very clear in exactly what took place, how long, and why it was being done. With the exception of the results section the presentation was easy to follow and right to the point.
Другие работы по теме:
Turtles Favorite Fish Essay Research Paper The
Turtles Favorite Fish Essay, Research Paper The project I am working on is called ?Which Type of Fish do Turtles Prefer to Eat?? I chose this topic because I wanted to see if the size and color of the
Theory Of Evolution Essay Research Paper I
Theory Of Evolution Essay, Research Paper I have always believed that it can take one person to get the ball rolling, but it takes a group to make an impact. Therefore, the concept of evolution via natural selection was a group effort.
Darwin Essay Research Paper Darwin
Darwin Essay, Research Paper Darwin’s theories and beliefs of his time caused a huge uproar among masses of people who knew of them. Even his scientist colleagues did not like the way some of his theories contradict beliefs in the Bible. One of the major theories that started it all was that of Natural Selection.
Lit Review
– Gay Studies Essay, Research Paper Personal Interest The social phenomenon that is of paramount interest to me is the sociological process that young homosexual men and women go through known as “Coming Out.” This is of interest to me, because of my personal experiences coming out, and of a personal desire to understand the struggles of homosexuals, especially young homosexuals on both a theoretical and individual basis.
Gender Selection Essay Research Paper The Future
Gender Selection Essay, Research Paper The Future is here The idea of being able to choose the gender of a child has not always been around. This controversy did not come about until recently because now we have the technology to perform this act of sex determination. Some say that we should be able to choose the gender of our children.
Buddhism Essay Research Paper The idea of
Buddhism Essay, Research Paper The idea of evolution by Darwin indicated that the world is not created by God, but through some kind of modification. This controversial idea is strongly objected by most of the religions, such as Catholic, Christian, and Islam etc. These religions sturdily believe that God is the creator of the world, the creator of everything.
Darwin And Science Essay Research Paper Charles
Darwin And Science Essay, Research Paper Charles Robert Darwin (1809-1882) was a British Scientist. He laid the foundation of modern evolutionary theory with his concept of the development of all forms of life through the slow-working process of natural selection. His work had a lot of influence on the life and earth sciences and on modern thought in general.
Much Better Than The Other Darwin Paper
Essay, Research Paper When Charles Darwin released his findings on Natural Selection in 1858, he did not do so in a vacuum. Many factors contributed to the formulation of his theories, and many popular misconceptions contradicted his conclusions to the point that he was reluctant to publish them for sixteen years.
Sea Turtles Essay Research Paper Lauren McGrorySea
Sea Turtles Essay, Research Paper Lauren McGrory Sea turtles have existed since their giant land turtle ancestors returned to the sea sometime during the Age of Dinosaurs. Although there were many species of sea turtles back then, only eight species have managed to survive modern times. The green, black, loggerhead, Kemp s Ridley, olive ridley, hawksbill, flatback, and leatherback turtles are in existence on our planet today.
Judicial Review Essay Research Paper Judicial ReviewThe
Judicial Review Essay, Research Paper Judicial Review The Supreme Court is the only court designated in the constitution. Within it is the Chief Justice of the United States, and eight associates. Being the highest court it is the last resort for all federal court questions. The Supreme Court has the power to determine whether something is constitutional or not, which makes them the final authority.
Sexual Selection As A Determinant Of Certain
Traits Essay, Research Paper If you were a male would you rather have a beautiful, impressive, long tail that attracts a lot of women or would you rather have a shorter, less attractive tail that enables you to escape from predators more easily? Living out in the wild among many potential predators, a shorter tail would seem more logical since it would be a more useful trait than a good-looking one.
Summary Of Origin Of Life Essay Research
Paper While it is key to the study of evolution to develop a theory to explain how species can change over time, it must also be supported by evidence from the scientific study of the natural world. One of the difficulties faced by many theories, such as Lamarck s, was a lack of such evidence. Even Darwin’s theory, which is the most widely accepted today, had to be proved with scientific advances and fossil evidence in the scientific community.
Antibiotic Resistance Essay Research Paper Darwins theory
Antibiotic Resistance Essay, Research Paper Darwin?s theory of evolution can be explained like this; the environment acts as a selective agent, weeding out organisms less able to survive. Darwin described natural selection as a process in which organisms become better adapted to their environment. The organisms that evolved with beneficial variations are more likely to survive and reproduce, they pass on the favorable genetic material.
Influences In Darwin
’s Thinking Essay, Research Paper Thomas Malthus and Charles Lyell were two figures who influenced Darwin’s theories. Malthus was an influence through his book on the population principle. Darwin had a
Evolution Through Natural Selection Essay Research Paper
Children often play a game called telephone, where one child whispers a statement into another child’s ear, and the statement is passed on to other children; at the end of the game the last child will repeat the statement that was told to him or her. The majority of the time, the statement said would be completely different than the original one.
Darwin 2 Essay Research Paper Natural SelectionCharles
Darwin 2 Essay, Research Paper Natural Selection Charles Darwin came up with the theory of evolution to explain the diversity, complexity, and origin of life. According to Darwin evolution takes place via Natural selection. Natural selection can explain diversity with in species, but I have yet to see anything that could make me believe that natural selection can create new species, or the origin of life.
Ridley
’s Sea Turtle Essay, Research Paper Sea Turtles Each species of sea turtle is distinctive in appearance and behavior, all sea turtles have certain characteristics in common the shell consist of a carapace (upper part) and plastron (lower part), which are joined together by cartilage called a bridge. in most species with the exception of the leatherback scutes cover the carapace.
Alligator Snapping Turtle Essay Research Paper Close
Alligator Snapping Turtle Essay, Research Paper Close your eyes if you re a turtle lover and try to image you self as one of the biggest freshwater snapping snapping turtles what would you do? Would you go on an eating frenzy or would you go for a swim? If you love turtles as much as I do then you will love to hear about one of the scarcest turtle alive to day.
The Painted Turtle Essay Research Paper The
The Painted Turtle Essay, Research Paper The turtle, he is an elusive creature. Hidden well in the water. He is also hidden well in his shell. The shell alone provokes our childlike curiosity to see what?s inside, to explore. The more we learn about them the more questions we have. How do they live, how do the reproduce, how do they as cold blooded reptiles survive the winter, and many other mysteries.
Green Sea Turtle Essay Research Paper Green
Green Sea Turtle Essay, Research Paper Green Turtle Introduction The Green Turtle (Chelonia mydas) is one of the many species of turtles that inhabits the vast oceans. The green turtle is named for the greenish color of it?s fat found under its shell. It is a large, heavy reptile, usually about 0.7-1.0 m in shell length and about 90-140 kg in weight.
Trainers Report Essay Research Paper PurposeThe purpose
Trainers? Report Essay, Research Paper Purpose: The purpose of this training session is to teach the trainee how to fold a turtle. In the Korean culture, by folding a thousand turtles, it brings truth, victory and luck to the person who is receiving it as a gift.
Anthropology Essay Research Paper AnthropologyMuch better than
Anthropology Essay, Research Paper Anthropology: Much better than the other Darwin paper July 20, 1998 ——————————————————————————– When Charles Darwin released his findings on Natural Selection in 1858, he did not do so in a vacuum. Many factors contributed to the formulation of his theories, and many popular misconceptions contradicted his conclusions to the point that he was reluctant to publish them for sixteen years.
Why Homosexuality Is Abnormal Essay Research Paper
Why Homosexuality is Abnormal? Michael Levin Levin gives two claims to support his views of homosexuality. Homosexuality is abnormal, therefore it is undesirable. Levin also gives explanation to why unhappiness is tied to the misuse of body parts.
Play Review On West Side Story Essay
, Research Paper Drama Play Review on West Side Story The musical Play that I did my review on was West Side Story by Jerome Robbins. I saw this play at the Woodland High School with my family. We went to see it because my older brother, Nick was in it.
Darwins Theory On Evolution Essay Research Paper
Discuss Evolution Theory according to Darwin In 1838, Charles Darwin put together his Theory on Evolution. Darwin tried to prove his theory that man was the center of the world and not God. He believed that evolution was gradual on both humans and on organisms. Darwin believed in something called natural selection; meaning genes are to be passed on from one generation to the next.
Evolution Essay Research Paper 1 Describe modern
Evolution Essay, Research Paper 1. Describe modern theory of evolution. Evolution simply describes the changes over time that occurs in organisms. Evolution as a whole can be more clearly describes by subdividing it into two separate categories macroevolution and microevolution. Macroevolution is evolutionary change on a grand scale that occurs over long period of time.
Hw Lab Essay Research Paper I TitlePopulation
Hw Lab Essay, Research Paper I. Title Population Genetics and Evolution: Hardy Weinberg Equation II. Hypothesis This lab is separated into four different cases. Within each of these cases, there are
Natural Selection Essay Research Paper In suggesting
Natural Selection Essay, Research Paper In suggesting the process of natural selection as the means resulting in evolution, Charles Darwin shows how evolutionary changes have occurred in organisms. Genetic change through time Understanding natural selection is paramount to our comprehension of evolution. is a much more accepted than the theory man has evolved from apes.
The Effect Of Violations Of Hardy-Weinberg Equilibrium
Conditions On The Allele Frequency Of Drosophila Melanogaster Populations Essay, Research Paper Introduction The interaction between genetic variation and natural selection is one of the most important concepts in modern biology. The product of this interaction, evolution, which is a change in a population?s allele frequency, is responsible for the great complexity and diversity of life seen on earth today.Allele frequencies of a non-evolving population (one in which the allele frequencies are not changing) can be elegantly modeled using the Hardy-Weinberg theorem.