While answering these multiiple related questions, please utilize Coyne's book, prior knowledge and/or outside research, and refer/connect your answer to the biological themes.
Thursday, April 8, 2010
Is Evolution All But Proven?
After reading through all of the evidence provided by Jerry Coyne, in your mind, are there any missing "pieces to the puzzle"? Are there questions remaining about certain aspects of the theory of evolution? If so, is there any evidence that would verify evolution once and for all? If you believe that evolution is as proven as any other scientific fact/principle and no further proof is needed, please provide a possible point of contention, a possible missing link, and disprove it.
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Someone wanting to dispute evolution might point out that closely related species ,as Coyne mentions at the beginning of the Origin of Species chapter, cannot interbreed because the offspring will most likely die.
ReplyDeleteThen why is it that all humans can breed with each other resulting in healthy, hybrid offspring? Because people evolved and adapted due to different environments with geographical barriers and different appearances and cultural ideals, how can we still reproduce, while similar animal species cannot.
One might answer this question by stating that although races are a product of geographical isolation, this does not mean people were reproductively isolated. According to Coyne,reproductive isolation causes perhaps the most important factor: "physiolog[ical]" differences" (Coyne 172. Because we are all physiologically the same we can reproduce healthy offspring.
One of the themes of biology is continuity in change, that genetic information can be inherited from parent to offspring. Of course, DNA is not invulnerable to change. With astronomically many cell divisions happening every day, multiplied by thousands to trillions (depending on the species) of nucleotides being cloned with each cell division, it is more likely than not that at DNA mutations occur. The process of crossing over in sexual reproduction provides even more chances for DNA mutations.
ReplyDeleteI think that if continuity in change is true, then evolution is inherently true. In a large population, a diverse variety of genes (and mutations) exists. The more diverse the gene pool of a population, the more likely that somewhere is the correct gene for adapting to a new environment. With myriads of opportunities for mutations every day, the gene pool of our biosphere is very diverse indeed. Individuals not fit enough to survive and reproduce in new environments will die, and no offspring are available to carry their genes. On the other hand, individuals fit enough to survive and reproduce in new environments will survive and reproduce, creating offspring that carry on their genes. Therefore, that evolution happens is a completely logical phenomenon.
Coyne has presented a lot of evidence in his book. I feel that the evidence is not to prove evolution, but to refute those who try to disprove evolution. Upon reaching understanding of what evolution is, it is difficult to explain how evolution can possibly not be true.
Of course, things that make sense are the most difficult to prove. As humans have probably not yet catalogued every species on earth, it is impossible to prove that all species evolved from a universal common ancestor. But I believe that it would make more sense to assume evolution to be true and to place the burden of proof on the shoulders of creationists, rather than putting the burden of proof on the shoulders of biologists.