Tuesday, May 17, 2011

Evolution :)


When you hear that word Evolution what first comes to mind? If you think it’s that present-day organisms are descendants from ancestral species that are different from the modern species then that’s correct. Evolution was first introduced by an early evolutionary philosopher named Charles Darwin, who had numerous observations about all of the plant and animal life that he encountered. While on his journey, that took him into the Galapagos Islands, Cape Horn, as well as into the Cape of Good Hope, Charles Darwin he began to observe, and soon questioned the belief that at one time the earth was young based on all of the geographic evidence that he observed. While in the Galapagos, Darwin began to study animals such as sea lions, fur seals, penguins, rice rats, spiders and smaller insects, as well as land birds and bats. Darwin’s main purpose while he was there, was to arrive at a conclusion of how all the animals got there. In this study, he was able to further prove his theory of natural selection. He realized that once all of these animals arrive here, they took on the duty of establishing themselves, as well as determining their own territories. Darwin noted all of the diversity and unity among living organisms, and therefore concluded that based on the environment that they live in, plants and animals develop characteristics that fit they environment. Erasmus Darwin was one of the first philosophers to formulate theories on evolution in Zoonomia also knows as the Laws of Organic Life. Erasmus questioned how one specie could evolve into another, and even went on to discuss how competition and sexual selection could affect that changed in species. He arrived at the conclusion that “The final course of this contest among males seems to be, the strongest and most active animal should propagate the species which should thus be improved.” Erasmus’s ideas seemed similar to another philosopher named Jean-Baptiste Lamarack. Lamarack took on the enormous challenge of learning as well as creating a new field of biology, and in the process coined the word “invertebrates.” Lamarack began working on invertebrates and took a great advancement over existing classifications. His theory was that acquired traits can be inherited, and that organisms are not passively altered by the environment, but instead changes in the needs of the organisms which live in the environment, thus causing changes in behavior. With changes in the species behavior, eventually over time this will result in the organisms evolving (adapting) to make it more favorable to its environment. While Lamarack’s theories were largely ignored, and often attacked, he was acknowledged as a great zoologist and a forerunner of evolution. Alfred Russel Wallace was a well-known English naturalist, evolutionist, geographer, anthropologist, social critic, and theorist who wrote one of the best known summaries Darwinism, where is described both Darwin’s position, as well as his very own. Darwinism fits into the category of natural selection. The fossil record has been completely against Darwinism from the beginning. With the fossil theory, yes it shows a change in the organisms that lived at different times, but it doesn’t show a steady change, instead it just shows one thing in the rocks, and then all at once something is fully formed, and from there it will stay the same. Wallace found himself working at a Collegiate School, and in doing so found some really important information on natural history and systematic. It was here that he made an acquaintance with another amateur naturalist named Henry Walter Bates. With all of Bates accomplishments, such as already being an entomologist, he soon caught the attention of Wallace. Soon after meeting Bates, both Bates and Wallace embarked on a journey in the Amazon and Malay Archipelago, to focus on their operations. At the beginning they stayed together, but within two years they split up and Wallace focused his activities in the middle of the Amazon and the Rio Negro regions, while Bates stayed in the Amazonian South America. It was here that Bates secured his reputation as a leading naturalist an entomologist. He contributed significantly in the early development of the Natural Selection Theory with his education in the concept of mimetic resemblance. Wallace’s main reason for going to the Amazon, was to investigate the causes of organic evolution. His interests ended up stretching in the management of natural science. Georges Cuvier was also a known naturalist, who saw organisms as integrated wholes, and in which each part’s form and function were integrated into the whole body. Not one part can be modified without impairing the functional integration. Cuvier didn’t believe in the organic evolution. Any change in an organism’s anatomy might have rendered it unable to survive. Throughout his life, Georges Cuvier studied the mummified cats as well as the ibises that Geoffroy brought back from Napoleon’s invasion in Egypt. In doing so, he was able to show that there was absolutely no difference from their living counterparts. Georges used this information as support in his claim that life forms didn’t just evolve over time. By organisms being functional wholes, any change in a single part would end up destroying the delicate balance. With Cuvier’s insistence on the functional integration, it led him to classify animals into four different branches: Vertebrata, Articulata, Mollusca, and Radiata. He was able to sort these out, because each are fundamentally different from each other, so therefore cannot be connected. If any organisms have similarities, it is only because of common functions not because of common ancestry. Cuvier’s theories were much the same as Lamarck, when it was suggested that animal morphology could be more changeable and affected by environmental conditions.

There are several different mechanisms in microevolution, such as mutation, genetic drift, migration and natural selection. Mutation is when genes randomly mutated a different color. For instance if someone was to have a group of black birds, and the brown randomly mutated into red, this would be known as mutation. Due to the fact that it cannot account for big allele frequency over one generation, particular mutation is rare. Genetic drift is what is known as random luck. In this case, more red genes ended up in the offspring than the black genes. Migration is what is known as a gene flow. For this instance, either black genes immigrated from another population, or some of the red genes emigrated. Last but not least, is Natural Selection, which is the main mechanism for the evolutionary process. In natural selection, populations can end up changing over generations, only if individuals that possess a certain heritable trait end up leaving more offspring than any other individuals. Nature is “selecting” only the individuals that are most fit in their environment. An example of this might be if the black escaped predation, and ended up surviving to reproduce more than the red genes, leaving more black genes into the next generation. Natural selection is known as the driving force of Macro and Micro evolution. Macro-evolution states that life is descended from a common ancestor, while Micro-evolution states that changes within a population of a single species occur over time. There are several different theories that act as evidence for evolution, including biogeography, morphology and even molecular data. In my opinion, all of the theories end up going together in one way or another. Although they all mean something different, there main idea all ends up centering on the same thing. Evolution started at one place or another, but yet no one knows exactly what started it. It’s an obvious statement that things have some reason or another that has caused a change. The most logical reason that I think, is that plants and animals changed based on their needs, and the environment that they live in. The question still lingers, reptiles have been around so much longer than human beings, yet humans are so much more evolved. Such as, humans are smarter than reptile’s right? So being with the fact that they have been around hundreds if not thousands of years before us, why aren’t they evolving at the same rate we are? Is there something stopping them, or could it just be the fact that maybe each species evolves at different rates, and then again there is still the possibility of if the environment that one lives in changes it as well.

So evolution has obviously made an impact of some sort or another true? Where exactly did we come from? Evolution is a broad topic, and most likely one that won’t ever really have an exact answer as to why things evolve the way they do or what causes it for that matter, or even the biggest question I still ponder, Why do humans evolve faster than reptile’s?


"Evolution Fossil Record." Straight Talk about Issues Affecting America Today: America's Christian Heritage, Separation of Church and State, Abortion, Evolution. Web. 15 May 2011.

"Charles Darwin and the Galapagos." Melissa D. Binde. Web. 15 May 2011.

"Evolution Intro 9th Grade 2009-10 by Stacy Baker on Prezi." Prezi - The Zooming Presentation Editor. Web. 15 May 2011. .

"Evolution 101: Microevolution." Understanding Evolution. Web. 15 May 2011.

"Evolution: Sex: Sex and the Single Guppy." PBS: Public Broadcasting Service. Web. 15 May 2011.

"The Alfred Russel Wallace Page." WKU IT ASA. Web. 18 May 2011.


"Evolution Islands." The Why Files
The Science Behind the News. Web. 18 May 2011.

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