How Does the Theory of Evolution Depend upon Genetic Variation - Essay Example

EVOLUTION The world is so various a place that it is not possible to know everything about it. It has so many different kinds of creatures, ecosystems, and physical features. Human minds are limited and much smaller than the world; they have also evolved out of the world and are a product and part of the natural world. It therefore follows that their perspective is limited and not objective. Although we can deduce some things from the evidence in front of us, it isn’t possible to know everything. Some religious people believe the human mind did not come out of nature but was placed in nature by God and is therefore more powerful than the natural world. I don’t think there is any evidence to support this idea. The truth is that the theory of evolution dictates which species continue to exist and which fail. It moulds and shapes the functions and appearance of each species. However, it does not guide them towards any one particular end. Evolution says that nature changes in a random way and that nothing is being progressed towards. Each step of evolution happens because of various circumstances none of which are planned. Animals might grow in a certain way because a forest fire has occurred or because it has been very cold for 50 years. These are random event that influence biology. There is not a shred of scientific evidence to say there is a plan behind it. The human mind always looks for patterns, even where there are none (Audi 29). Religion says that “God has a plan”; evolution says “There is no plan.” In the course of doing all of this evolution depends on a number of important things. Among them natural selection, heredity and genetic variation. In this, the 201sth anniversary of the birth of the great British biologist and scientist, Charles Darwin, it is fascinating to look at how his powerful theory of evolution is still a subject of debate and how exactly it operates in nature. Eight-four years ago The Scopes Trial highlighted how intransigent many people were to teaching the theory of evolution. They believed that it was directly contradictory to their faith that God created the world and everything in it. Indeed, the theory was a threat to their way of life, the way they thought about themselves. They used lawsuits to try to prevent evolution from being taught. Not much has changed in the last 84 years. The debate still rages in school boards across America. While most of the rest of the developed world would blanch at the notion of teaching Creationism—the idea that God created the world and everything in it—in the United States there are institutes and public figures who promote the idea. But that is only the political and cultural context. To truly understand evolution, it is important to understand its foundation stone: natural selection. What is the difference between saying that a duck has webbed feet because it needs them to swim and saying that a duck is able to swim because it has webbed feet? The important question is how did the duck come to have webbed feet. In the first case natural selection allowed the duck to have webs to swim; the duck didn’t look down, see it had webs, and decide to start swimming. This is a bit of a “duck and egg” questions: which came first. According to evolutionary scientists it is likely that a duck-like creature with unwebbed feet was living near water (Bowler 78). It slowly began to eat more and more food from the water and eventually the duck’s with more web-like feet began to survive more because they were better able to eat. The truth is that heredity and genetic variations are only spokes in the wheel of natural selection (Margulis 65). Heredity is what is passed down from one generation to the next in the form of DNA, not acquired characteristics. Genetic variations are occasional unpredicted differences in DNA, perhaps mutations. These affect natural selection, but are secondary to things such as environment. Animals who can adapt more quickly or who have certain characteristics that improve their ability to reproduce will naturally pass on their genes and the variations of these genes more successfully than those that cant. Recently, scientific thinking about heredity and genetic variations have been turned on its head. A Japanese scientist has begun to suggest that some acquired characteristics may be passed down too. This changes the way we think about natural selection. The scientist realized that all animals live longer if they have a lower caloric intake, but the rotifiers he studied, when starved, would pass on longevity to their children. The starved rotifiers produced an enzyme called catalase. According to the Economist: This enzyme degrades hydrogen peroxide, a highly reactive chemical that creates cellular damage of the sort associated with ageing. Dr Watabe found that the offspring of calorie-restricted mothers have more catalase than those of mothers who were fed without restriction. The researchers also detected higher levels of the enzyme in the eggs of calorie-restricted mothers, so it could be that their offspring are simply endowed with the stuff. A more intriguing possibility, though, is that the relevant genes are affected by epigenesis, a process in which chemicals attached to the DNA control its activity. Epigenetic modifications are often retained when cells divide, and can sometimes be passed on to offspring (The Economist). This may well change how we think about the theory of evolution. There may be other factors at play that we have yet to consider. Evolution is a complex theory. It has its controversies, its supporters and deniers. Clearly the debate between creationism and Darwinism is a loaded one with angry opponents on both sides. Everyone has a lot invested in the subject because it strikes at the core of the most philosophical issues: Why are we here? What are we here to do? How should we live? Much of the debate has been through the courts that have consistently ruled in favor of evolution. It is important not to get caught up in this debate which I believe has been won by the evolutionists, but instead look about what it says about our society and the way we live now. It is important to always be thinking about and rethinking the constituents parts of the theory of evolution: natural selection, heredity, and genetic variation. Works consulted Apple, Michael W. March 2008. “Evolution Versus Creationism in Education.” Educational Policy. Volume 22 Number 2. p 121. Audi, Robert. “Religion and the politics of science can evolutionary biology be religiously neutral?” Philosophy and Social Criticism. Vol 35 Nos 1–2. p 31. Benz, Richard. Ecology and Evolution: Islands of Change. Arlington, VA: NSTA Press, 2000. Bowler, Peter J. 2003. Evolution: The History of an Idea. L.A.: University of California Press. Dennett, Daniel Clement. Darwins Dangerous Idea: Evolution and the Meanings of Life. New York: Simon & Schuster, 1995. The Economist. “Thanks, Mum! An obscure group of animals may reveal the secret of elongating life.” Sep 30th 2010. http://www.economist.com/node/17144833?story_id=17144833 Eldredge, Niles. Darwin: Discovering the Tree of Life. New York: W.W. Norton & Company, 2005. Margulis, Lynn. Microcosmos : Four Billion Years of Evolution From Our Microbial Ancestors. New York: Summit Books,1986. Read More