While discussing evolution, Terry Pratchett said “Most species do their own evolving, making it up as they go along, which is the way Nature intended. And this is all very natural and organic and in tune with mysterious cycles of the cosmos, which believes that there’s nothing like millions of years of really frustrating trial and error to give a species moral fiber and, in some cases, backbone.” This quote is a humorous way of basically breaking evolution into very simple terms. Evolution is a controversial and touchy subject in schools, but can be researched from different points of view.
There are a few people who have made dramatic contributions to the world of evolution and what evolution entails. Jean Baptiste Lamarack thought that organisms inherited the traits that had acquired during their parents’ lifetimes. “‘Lamarckism’ or ‘Lamarckianism’ is now often used in a rather derogatory sense to refer to the theory that acquired traits can be inherited.” Lamarack believed that a change in the environment caused needed changes in the organisms in that environment, which could cause changes in their behavior. He fully believed that organisms altered their behavior in response to the changes in the environment. This in turn modified the organism’s organs, which their offspring inherited, becoming evolution. For most people, this made the most sense at the time; if the parents had it, why couldn’t the babies? Unlike Charles Darwin, Lamarack believed that all living things evolved in a continuously upward direction through simple or more complex forms, eventually working toward “human perfection.” Lamarack also believed that species never become extinct, but instead changed into animals, such as a land dinosaur into a whale or a bird.
Charles Darwin, on the other hand, presumed the development of life from non-life forms and stressed a purely naturalistic and undirected “descent with modification”. Darwin believed strongly in natural selection and a “slowly but surely” change when it came to organisms. He popularized the theory of humans being animals and deriving from apes, which upset many church nations and numerous people as most British occupants were strong believers in the Bible. While on a journey on the HMS Beagle, Darwin had his major breakthrough in the Galapagos Islands. He noticed that each island had their own forms of a bird: finches. They were extremely closely related but diverse in many important ways. He theorized that as a random genetic mutation occurs within an organism’s genetic code, only the beneficial mutations remain because those mutations aid survival. This process is widely known as natural selection. Darwin’s theory is now in turmoil due to tremendous advances in molecular biology.
Karl Popper, a popular philosopher of science, was known for being extremely logical and was also very beneficial to the Evolution theories. Popper focused on separating science from pseudo-science. Psuedo-science is defined by Webster’s Medical Dictionary as a system of theories, assumptions, and methods erroneously regarded as scientific. Popper accepted psuedo-science but denied that they were any part of general science. He also did not believe that Darwinism was a testable theory. He was widely accepted in Europe, particularly England. Popper was really critical of attempts to turn evolution theory into a fact. He said, "The idea of a law which determines the direction and character of evolution is a typical 19th century mistake arising out of the general tendency to ascribe to the natural law the functions traditionally ascribed to God."
These scientists not only contributed ideas and ways of thinking to the evolution theory, but also added a face to all of the research and hard work that has been put into this topic.
Although these scientists had altering views of evolution, there are some things that a wide variety of scientists agree on. Mutation, migration, genetic drift, and natural selection are all major factors that affect the conclusions of biology. During mutation, genes “randomly” mutate to other genes. This process is extremely rare because the process alone can’t account for a major change in the allele frequency over one generation. Certain mutations can either be beneficial, neutral, or harmful to the single organism. Mutations do not attempt to supply what the organism needs, because they are random. Whether a particular mutation happens or not, it’s not related to how useful that certain mutation could be. Migration, also known as gene flow, is when organisms with certain genes immigrate or emigrate to another region, carrying those genes with them. A number of different species have migratory instincts which develop in different species for many different reasons. Most of the time migration is a response to population pressure (which also can cause evolution) such as the “leave somewhere cold for somewhere warm, then return” pattern. Things such as climate changes may have had an affect in forming or shaping different migratory patterns, which can also be described as evolution. Birds commonly follow this pattern, therefore migrating not only themselves, but also the genes that they carry. These genes can then remain in a different area. Genetic drift, or allelic drift, is when certain individuals may by chance, leave behind more descendents and genes than some other individuals. Then, the genes of the next generation are the genes of the “lucky“ individuals but not really the healthier or better individuals. Unlike natural selection, genetic drift occurs completely at random. Even though it’s a mechanism for evolution, it has no part in an animal’s adaptation. The changes that occur are not driven by environmental or adaptive pressures. The changes can be beneficial, neutral, or very detrimental to the animal that the changes have occurred to. Genetic drift happens to all populations. Now, natural selection is a pretty simple concept but can become extremely complex. For example, if there were two worms in a toy Barney doll bin and a predator was hungry, these two worms could be in trouble! One of the worms is the same color of Barney (purple) while the other is, well, we can say White. Now, the bird is more likely to see the white worm than he is the purple colored one. This causes the white worm population to decrease, while the purple worm population can rapidly increase. In this case their color saves them from predation and allows them to survive in order to produce their color more frequently.
Scientists often look to biochemical information to learn more about evolution. Biochemistry is the universality of a genetic code. For example, the human versus ape chromosome. Humans have 23 pairs of chromosomes while apes have 24 pairs. The human Y chromosome also has huge affects as the Y chromosome is passed mostly unchanged from the father to the son with occasional mutations or differences. These mutations are said to be the basis of human origin from apes. Embryology is also commonly looked to. This means that different species who may be in the same class (ex: mammals) often have extremely similar embryos. This case is true even if the adult forms are quite different from the adolescent forms, such as in the case of a caterpillar and a butterfly. Fossils, from my understanding, are the largest pieces of evidence of evolution. These include the evolution of vertebrate legs, birds from dinosaurs, mammals evolving from egg laying creatures, and whales that have evolved from land bearing animals to sea depending mammals. Apart from fossils, comparative anatomy is also discussed and analyzed when looking at evolution. Comparative anatomy is when anything similar is “evidence for evolution.” In simple terms, this can basically mean that completely unrelated species that happen to live in similar environments have evolved from similar forms. This may be possible in the case of a cat and a dog, because they have the same body shape.
Microevolution and Macroevolution cover the same topics, but have very diverse “specialties”. Microevolution is on a small scale, such as in a single population. It’s defined as a change in gene frequency in a population and that population has a group of organisms that share a common gene pool. For example, all of the individuals of one beetle species living on a particular mountaintop. Macroevolution is on a bigger scale. It refers to evolution about the species level. A macroevolutionary lense would focus on the tree that a beetle lives on, rather than it’s opposite, the microevolutionary lense, which would focus on the beetle species itself.
Although there are a lot of people who fully believe in the theory of evolution, I believe it is what it’s called: a theory. We don’t have any legitimate solid proof that that’s actually what happened. We claim to have come from apes, but how do we really know? Even after looking at the anatomy, genes, and fossils of apes, there are a number of scientists who still aren’t sure. I grew up in a very Christian home, and believe strongly in the Bible. The Bible claims that God created us in one day, man first, than the woman from the man’s ribs. I also believe that God made the animals. Now, in regard to all of the evidence that I, and many other scientists, have discovered and researched, I do believe in adaptation. Animals need to continually adapt to their environment. But adaptation and evolution are two very different concepts that seem to have commonly been crossed. The fossils and genes that are always looked to for evidence of evolution, is actually, in my opinion, evidence for adaptation. Now, regarding the theory that humans have derived from apes; this I do not believe at all. Apes and humans are too diverse, and throughout my research, I have found no physical evidence that this “evolution” is possible. Researching evolution and the theories behind it has really been an interesting topic, but I can understand why it is so controversial.
Works Cited
Charles Darwin (1809-1882). (n.d.). BBC. Retrieved May 9, 2011, from http://www.bbc.co.uk/history/historic_figures/darwin_charles.shtml
Cline, A. (n.d.). Karl Popper and Evolution. About.com. Retrieved May 9, 2011, from http://atheism.about.com/b/2006/06/20/karl-popper-and-evolution-is-evolutionary-theory-based-on-a-tautology.htm
Darwin's Theory of Evolution. (n.d.). All About Science. Retrieved May 9, 2011, from www.darwins-theory-of-evolution.com/
Evidence for Evolution--Embryology. (n.d.). New York University. Retrieved May 11, 2011, from http://www.nyu.edu/projects/fitch/courses/evolution/html/embryology.html
Genetic Drift.(n.d.). Evolution 101. Retrieved May 9, 2011, from http://evolution.berkeley.edu/evosite/evo101/IIIC1Mutations.shtml
Genetic Drift as a Mechanism of Evolution: Random Genetic Changes Help Drive Evolution
Suite101.com. (n.d.). Suite101.com: Online Magazine and Writers' Network. Retrieved May 11, 2011, from http://www.suite101.com/content/genetic-drift-a124881
Grabianowski, E. (n.d.). How Animal Migration Works. How Stuff Works. Retrieved May 9, 2011, from animals.howstuffworks.com/animal-facts/animal-migration3.htm
Jean-Baptiste Lamarck (1744-1829). (n.d.). UCMP - University of California Museum of Paleontology. Retrieved May 9, 2011, from http://www.ucmp.berkeley.edu/history/lamarck.html
Migration.(n.d.). Evolution 101. Retrieved May 9, 2011, from http://evolution.berkeley.edu/evosite/evo101/IIIC1Mutations.shtml
Mutations. (n.d.). Evolution 101. Retrieved May 9, 2011, from http://evolution.berkeley.edu/evosite/evo101/IIIC1Mutations.shtml
Natural Selection. (n.d.). Evolution 101. Retrieved May 9, 2011, from http://evolution.berkeley.edu/evosite/evo101/IIIC1Mutations.shtml
Sonleitner, F. J. (n.d.). What Did Karl Popper Really Say About Evolution?
NCSE. NCSE
National Center for Science Education - Defending the Teaching of Evolution in Public Schools.. Retrieved May 9, 2011, from http://ncse.com/cej/6/2/what-did-karl-popper-really-say-evolution
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