NOTE: Free essay sample provided on this page should be used for references or sample purposes only. The sample essay is available to anyone, so any direct quoting without mentioning the source will be considered plagiarism by schools, colleges and universities that use plagiarism detection software. To get a completely brand-new, plagiarism-free essay, please use our essay writing service.
One click instant price quote
Natural Selection process by which populations become adapted to the environment. The fitness of an individual is measured by how well its offspring reproduce i. e. how many offspring that survive and reproduce does an individual produce? Charles Darwin studies and close watched peppered moths (Boston Betularia) in their natural habitat. The peppered moths are light colored with darker areas of color.
Like humans, however, these moths can be found in a range of pigmentation from very black to very white and all shades in between. He watched during the Industrial Revolution in the middle of the 18 th century. Soot from the factories was starting to discolor the trees making the moths visible to passing predators. The different colored moths all belong to the same species; they reproduce with each other, and the color difference depends primarily on alternate alleles for a single gene.
The black moths were presumably produced by mutation: biochemical change in DNA that makes up the genes for a trap. Under the Hardy-Weinberg Principle it is stated that the frequency of dominant and recessive alleles is the same from generation to generation. This was not he case. Peppered moths rest during the day on tree trunks, where they are vulnerable to being eaten by birds. In pre-industrial England, tree trunks were gray. Gray moths are well camouflaged on gray tree trunks; black moths stand out.
It has been shown experimentally (by Kettle well) that in areas with gray tree trunks, black moths are much more likely to be eaten by birds than are gray moths (presumably because black moths are much easier for the birds to see. ) In industrial areas, because black moths avoided being eaten by birds, they survived better and therefore reproduced more (had higher fitness. ) As a result, each generation, more and more of the offspring born came from black parents and inherited the black coloration, since the color differences between moths (gray versus black) are genetic. After many moth generations, almost all the moths in industrial areas were black. The black moths became a subspecies of the Boston betula ria. Black coloration is an adaptation to an environment with black tree trunks; that is, it has evolved through natural selection because black individuals have higher fitness in forests with black tree trunks than do gray moths. Darwin did many experiments to prove the evolution in the moths.
He tested the chemicals in the soot to make sure that they were not causing a mutation in the moths. The chemical ratio was found to be higher than normal. Scientists concluded that it was mutation. He then put a spot on the underside of the moth so that he could keep an accurate record of the census of moths that had evolved and were now black. He placed the dot of paint on the underside so that in the rain the paint would not come off. Another reason for the placement of the paint was so if the moth was attached then the paint would not scratch off.
The paint was a good method of distinguishing the moths. It is like tagging birds or other animals. If the moths had not been recaptured then Darwin would not have know how many moths returned alive. Since it was a possibility that the paint could come off, his count was not completely accurate. Another experiment was preformed, in this Darwin put light moths on a dark tree. This showed that the chief predator of the moth was the birds.
When both coloration of moths were placed on the tree trunk it showed that the light mother were most likely to be prayed upon. In a posted forest the dark moth is most apt to survive and flourish. In the unpolluted forest where the trees were still covered with lichen the light moths survive better. I feel that it is not likely that the dark colored moths existed before the Industrial Revolution.
If they had been around they would have quickly died out because the trees were not covered in soot, they were light. This altered the generic equilibrium between the light and dark moths, the dark became dominant in this area. The population of the light colored was no longer able to survive in the forests that were coated in soot. The remaining light colored moths migrated to other forests where thy could survive. This ment that even more dark moths were in the forest where Darwin was studding the moths Jean Baptiste Pierre Lamarck was a French botanist and invertebrate zoologist who formulated one of the earliest theories of evolution.
He was the main pre-Darwinian evolutionist. Sent to a Jesuit school in Amiens, Lamarck received a classical education until 1759. That year, his father died, and Lamarck entered the military and began to study plants. In 1768 he left military service and studied medicine in Paris for four years, during which time he became interested in meteorology, chemistry, and shell collecting. At the same time, he wrote a work on his botanical observations, then French naturalist George Louis Buffon published in 1779 as Flore Fran?
ois (Plants of France). As a result of the book and his friendship with Buffon, Lamarck was elected to the Academy of Sciences. This election was a prestigious honor. Lamarck's real contribution to biology lies in his division of animal life into the vertebrate and invertebrate categories. He recognized that there was a major break along the lines of those species (fish, apes, people, horses, cats, dogs) that have backbones, and those species (lobsters, crabs, insects, coaches, snails, oysters) that have none. Lamarck's controversial reputation comes from the belief that he asserted that living beings change by consciously willing to change.
Lamarck offered a theory of evolution in the early 1800 s (the year that Charles Darwin was born). Lamarck's First Law stated: frequent and sustained use of any organ gradually strengthens, develops, and enlarges that organ, and gives it a strength proportional to the time that is has been used. This first law is based on the common observation of the development of as musculature and the immune system through protracted use, and it is not unreasonable. However, his Second Law is untrue: Everything which nature has caused individuals to gain or lose as a result of the influence of environmental conditions to which their race has been exposed is conveyed by generation to new individuals Lamarck's concept of evolution was discredited because he emphasized the inheritance of acquired characteristics as a mechanism of evolution. Do we not therefore perceive that by the action of the laws of organization... nature has in favorable times, places, and climates multiplied her first germs of animality, given place to developments of their organizations, ...
and increased and diversified their organs? Then... aided by much time and by a slow but constant diversity of circumstances, she has gradually brought about in this respect the state of things which we now observe. How grand is this consideration, and especially how remote is it from all that is generally thought on this subject! Text of a lecture given by Lamarck at the Mus?
e National d Histoire Naturelle, Paris, May 1803 Lamarck's scientific theories were largely ignored or attacked during his lifetime; Lamarck never won the acceptance and esteem of his colleagues Buffon and Cuvier, and he died in poverty and obscurity. Today, the name of Lamarck is associated merely with a discredited theory of heredity, the inheritance of acquired traits. However, Charles Darwin, Lyell, Haeckel, and other early evolutionists acknowledged him as a great zoologist and as a forerunner of evolution. Would Lamarck have agreed with Darwin?
That is the question. Since Lamarck believe that creatures willed themselves to change, he would have felt that the moths felt the need to change. He may have supported natural section but only in the case that the moths knew that they had to change to survive. Darwin believe that it was a natural process that took place over time, throught many generations.
The fossil record can help to show evolution. The record shows slow, gradual evolution occurred, it was observed that a change took place over a certain period of time. It didnt happen in a night. After all, if life took millions of years for the earth to arrive at its present state of development.
The fossils show saddle change but if compare two fossils with a span of 1, 000 years or so you would be able to clearly see the change. After periodic occurance's of extinction there was mass growth. This happened because when the organisms died they rotted and decayed which mad the soil more fertile and supple. A good example of this is in a forest fire when the trees and the mat of vegetation on the forest floor burn. It gives off oxygen and clears out the dead vegetation to allow for new growth. These new forms flourish from the fire.
When England passed its clean air acts in the 1960 s the soot was not coating the trees anymore because position was minimized. This put the dark colored moths at a disadvantage. Now the birds could see the dark moths on the light trees. Slowly the majority of moths became light colored again.
Since the DNA code is basically the same in all organisms this suggests that all of a species can be traced back to a common ancestor. With evolution this suggests that all DNA stays primarily but slight changes may cause changes in appearance such as with the moths changing shades. Evolution uses genetic engineering techniques. Why polar bears have white fur.
Polar bears have white fur so that they blend in with their artic habitat. If polar bears had different color fur then their predators would have easily spotted they and the population would be in danger of extension. The white fur blends in with the snow and the ice. They are suited for their enviroment.
Dinosaurs are still around. Their structures remain in birds. The bird is the most close related animal to the dinosaurs. Its wings were found in dinosaurs such as taryldactles. Therefore dinosaurs exist through their relative, the bird. evidence is overwhelmingly in favor of birds being the descendants of a maniraptoran dinosaur, probably something similar (but not identical) to a small dromaeosaur.
In 1860 a transitional form between two vertebrate groups (traditional reptiles and birds) was found; just what Darwin expected would eventually be found. Many scientists saw incredible similarities between birds and the theropod dinosaurs. In short birds are avian dinosaurs existing today. The disappearance of the dinosaurs was caused by a meteor hitting earth. The Chicxulub Crater (where the meteor is supposed to have hit) is dated back to 65 million years ago and is over 10 kilometers in diameter. Also tektites and stishovites, rocks that are made from great heat and pressure, have been found to be around 65 million years old.
They are most likely caused by a cosmic collision. Louis Alvarez came up with the theory of a Nuclear Winter causing the demise of the dinosaur. When the asteroid crashed into the earth a huge amount of dust was thrown into the atmosphere, blocking out the suns rays. This would stop all photosynthesis causing the death of most of the plant life, meaning death for the herbivores due to lack of food. This in turn would devastate the carnivora in the food chain. The temperature would also drop and extinction would not be determined by the dinosaurs eating habits, it would affect them all the same.
In the best scenario, the temperature drop would just slow the dinosaur down, preventing it from getting enough food. Charles Darwin was born on February 12, 1809 in Shrewsbury, England. He was the British naturalist who became famous for his theories of evolution. Like several scientists before him, Darwin believed all the life on earth evolved (developed gradually) over millions of years from a few common ancestors.
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 variations 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 specimens for further study. When Darwin return to London Darwin conducted thorough research of his notes and specimens. Out of this study grew several related theories: one, evolution did occur; two, evolutionary change was gradual, requiring thousands to millions of years; three, the primary mechanism for evolution was a process called natural selection; and four, the millions of species alive today arose from a single original life form through a branching process called specialization. Darwin's work had a tremendous impact on religious thought. Many people strongly opposed the idea of evolution because it conflicted with their religious convictions. Darwin avoided talking about the theological and sociological aspects of his work, but other writers used his theories to support their own theories about society.
Darwin was a reserved, thorough, hard working scholar who concerned himself with the feelings and motions not only of his family, but friends and peers as well. I read the conclusion and recapitulation in the book, this was chapter 14. Here is a break recap of it. As natural selection works solely by and for the good of each being, all corporeal and mental endowment will tend to progress toward perfection.
This was the main idea in the book. Darwin felt that only the strongest organism and the one that was best adapted to its surrounding would survive, he called this idea survival of the fittest. Darwin's principles that of survival of the fittest and natural selection pertain to developmental psychology. The processes of natural selection works equally over all parts and forms of function. If something is functional if it is adaptive, mental activity and behavior have function too. Darwin realized that developmental tradition have current forms had several previous forms and will have future forms.
Behavior has form. Patterns of behavior in all species tend to follow an orderly genetic sequence in their begining's. I feel that Darwin was correct in most of his theories. Many of them have been proven even more so since his lifetime. He contributed a huge amount to the sciences especially in the field of evolution. This book helped me to better understand his veiw's and stand on evolution, I also learned what made him person this topic.
Free research essays on topics related to: polar bears, 65 million years, charles darwin, millions of years, plants and animals
Research essay sample on 65 Million Years Millions Of Years
