Tuesday, June 1, 2010

Evolution


     Because of the plentiful supply of evidence consisting of embryology, cellular biology and paleontology, evolution is the best explanation of biodiversity. “To an evolutionary biologist, evolution is a change in the proportion of genes present in an existing population” (Andrew). The evolution-creationism debate can be traced back as far as ancient Greece but has more recently been between Bible followers and followers of the scientist, Charles Darwin. In the simplest terms, Darwin realized that individuals in a species have varying characteristics, and that those that are best adapted to their environment are more likely to survive and breed, causing the maladapted individuals to be eliminated over time.
    
     “In embryology, the developing fetus is studied, and similarities with other organisms are observed” (Cobb). For example, at their earliest stages, different mammal species look almost identical in the embryo and are almost impossible to distinguish. Since many species develop similarly and start off in similar shapes, embryology is a strong independent line of evidence that we originated from a common ancestor and that evolution did in fact occur. It is important to note that we didn’t come from other mammals such as chimpanzees; we just branched off from them at some point.
    
     “The Second Law of Thermodynamics states that all things in the universe are undergoing a continual process of decay. That process causes a decrease in the complexity of all things. Yet evolution requires the opposite to occur – namely, that all things evolve from a simple state to a state of greater complexity” (Thomson). This statement is based on a complete misconception as to the mechanisms of the second law. The second law states that the total entropy – or amount of energy unavailable for work during a thermodynamic process – cannot decrease. The Second Law also states that parts of a system can decrease in entropy as long as other parts endure an offsetting increase. For example, if the sun pours heat and light onto it, our planet can become more complex. The increase in entropy associated with the sun’s nuclear fusion more than balances the scale. It is for this reason that when simple organisms consume other forms of life and nonliving materials, they can fuel their rise toward complexity (Rennie).
    
     “Even in cell biology, at the level of the individuals cell, there is evidence of evolution in that there are many similarities that can be observed when comparing various cells from different organisms” (Cobb). Through cellular biology, we can see how similar the cells of different organisms are despite differences in size, shape, capabilities, and intelligence. This is because the DNA for supporting essential components of life is very similar and consistent across the wide and diverse spectrum of species that inhabit Earth. For example, we share 50 percent of our DNA with bananas, 60 percent with fruit flies, 98 percent with chimpanzees, and 99 percent with every other human. The same relationships that can be observed when analyzing the structures of organisms can be seen in DNA sequences further supporting that Darwin’s theory of evolution is the best explanation of biodiversity.
    
     “The ethical argument of the creationists is that the reductionistic materialism of Darwinian science is ethically degrading. If Darwinians persuade people that they are nothing but animals and therefore are not elevated above other animals by having been created in God's image, people will not respect God's moral law or see the unique moral dignity of human beings. Instead they will become selfish hedonists in the pursuit of their animal desires” (Arnhart). Darwinians reason that as the rational and naturally social animals human beings are, we have social instincts allowing us to care for others. We are also capable of creating moral rules making it possible for us to satisfy our social needs. For example, if children weren’t cared for by their parents or people assuming parental roles, the human species would not survive. We can therefore see how natural selection has given humans the natural desire to parent offspring and created the moral bond between parents and children.
    
     Our abundant and extensive fossil record is perhaps the best evidence of evolution. “By placing fossils together based on their ages, a gradual change in form can be identified, which can be carefully compared to species that currently exist” (Cobb). Analyzing the placement of fossils within the ground and using techniques like carbon dating to determine their age allows paleontologists to place fossils in chronological order. This makes it possible for them to note similarities with currently existing species. Using our fossil record, we can very clearly see that countless species have gone extinct. Although our fossil record is incomplete, careful analysis of habitat, environmental factors at various points of time, characteristics of extinct species, and characteristics of currently existing species can compensate for missing parts of the fossil record making paleontology an excellent source of evidence for evolution and natural selection (Cobb).
    
     There is an overwhelming amount of evidence supporting evolution including embryology, cellular biology, and paleontology. But what makes evolution so scientifically strong isn’t just the many strong lines of evidence that support the same thing, but the fact that each is completely independent from the others. Embryology is a strong piece of evidence because it shows how certain species develop similarly and start off in similar shapes allowing us to infer that these species have a common ancestor. Cellular biology allows us to see how similar various genetic codes and cells from different organisms are. It also allows us to see the same relationships between the structures of organisms in DNA sequences. Last of all, our extensive and abundant fossil record shows that countless species have gone extinct. When fossils are placed in chronological order, a gradual change in form can be identified which can carefully be compared to species that currently exist. Most of the opposing views on evolution are derived from a complete misconception as to the mechanisms of evolution. It is for these reasons that evolution is the best explanation of biodiversity.

Works Cited

Andrew, Susan. "Evolution." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. 3rd ed. Vol. 2. Detroit: Gale, 2004. 1538-1542. Gale Virtual Reference Library. Web. 18 May 2010.

Arnhart, Larry. "Evolution–Creationism Debate." Encyclopedia of Science, Technology, and Ethics. Ed. Carl Mitcham. Vol. 2. Detroit: Macmillan Reference USA, 2005. 720-723. Gale Virtual Reference Library. Web. 18 May 2010.

Cobb, Bryan. "Evolution, Evidence of." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. 3rd ed. Vol. 2. Detroit: Gale, 2004. 1544-1546. Gale Virtual Reference Library. Web. 18 May 2010.

John Rennie, "15 Answers to Creationist Nonsense", Scientific American Magazine, July 2002.

Thomson, Ker C. "Physical Laws Support Creationism." At Issue: Creationism vs. Evolution. Ed. Bruno J. Leone. San Diego: Greenhaven Press, 2002. Opposing Viewpoints Resource Center. Gale.  27 May. 2010
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