Natural Selection

Sean Nightingale

Bio 101

Professor Ralph Alcendor

12/9/06

Research Paper

Natural Selection

Charles Darwin in his book, On the Origin of Species, presents us with a theory of natural selection. This theory is his attempt at an explanation on how the world and its species came to be the way that we know them now. Darwin writes on how through a process of millions of years, through the effects of man and the effects of nature, species have had a trial and error experiment ongoing. It is through these trials that the natural world has developed beneficial anomalies that at times seem too great to be the work of chance.

Darwin writes on how a species will adapt to its surrounding given enough time. When an animal gains a genetic edge over its competitors, be they of the same species or of another genus altogether, the animal has increased its chance of either procreation or adaptation. When this animal has this beneficial variance, the advantage becomes his and because of this, the trait is then passed on to the animal's offspring.

The theory of natural selection is not limited to inheritable and beneficial variations of a species. It also relies a great deal on the population growth and death of a species. For a species to continue to exist it must make sure of a few things. It must first produce more offspring than survive. If this is not done then the species is obviously going to die off. It is also important for the species to propagate at such a rate as to allow for variance, for it is variance that will ultimately allow the animal to exist comfortably in his surroundings. In his studies, Darwin was led to understand that "...the species of the larger genera in each country would oftener present varieties, than the species of the smaller genera;" (p. 55). Thus the larger species would adapt while the smaller one would not. And to quote Darwin again, "...if any one species does not become modified and improved in a corresponding degree with its competitors, it will soon be exterminated." (p. 102)

Extinction, although not as pleasant a concept as the idea of adapting to ones surroundings, plays just as large a role in natural selection as anything else. As one adaptation of a species proves beneficial, and as that variation begins to propagate, the original, less advantageous variant will die off. It is the unchanged species that are in immediate conflict with the species undergoing the natural adaptation that stand to suffer the greatest.

One of the strongest arguments presented to evolutionists pertains to the formation of organs of extreme perfection and complication. In On the Origin of Species, Darwin pays particular attention to this question and gives the problem its deserving time. For the purpose of defending his theories, he sites the eye as the organ of extreme perfection. It is true that the eye is a fabulous tool. A light sensitive optic nerve sits at the back of a mechanism that man was incapable of duplicating until the early nineteenth century. A complex series of lenses bend light in such a way that it is focused onto the optic nerve, which can then, in turn, read the light and produce an image in the brain. This is a neat trick, and unfortunately for Darwin a complicated question. To look at the origin of any organ of extreme perfection Darwin found it necessary to trace the lineage of the animal (the one housing the organ) back to its formative ancestors. This is, unfortunately, quite difficult and improbable of success. Therefore the only approach to take in this case is to look at a different species that came from the same parent form, or as Darwin puts it, "collateral descendants." This is not possible, however, with reference to vertebrates for even the farthest of our collateral brothers have fully functional eyes. Instead Darwin delved into the realm of the Articulata. In the Articulata Darwin found an optic nerve covered with pigment and little more. This nerve is merely a light sensing freckle and can be traced through a series of branching and improvements until we can see it approach perfection.

"...bearing in mind how small the number of living animals is in proportion to those that have become extinct, I can see no very great difficulty...in believing that natural selection has converted the simple apparatus of the optic nerve merely coated with pigment and invested by transparent membrane, into an optical instrument as perfect as is possessed by any member of the great Articulate class." (188).

After millions of years of evolution and natural selection, why is it not possible that a thing as perfect as the eye has been developed. It is hard, however, to believe in this whole-heartedly. The more I read of Darwin, the more I begin to see the holes in the theory. My belief does not swing towards the thought of creationism. To me that is not an option. However, Darwin has done a great job of stating the arguments and as best a job answering them as he could. It is very difficult to respond to difficult questions with nothing but theory to back them up. He has, nonetheless, defended them to the best of his abilities and his responses are, with a little faith in science, more than acceptable.

Yet another quibbling point brought to attention by Chuck is the existence of neuter insects. The question being that if natural selection only works through a process of slight variation, and only the beneficial variants remain, then why are there neuter insects? Why would nature have seen it fit to not only create these unfortunate slaves but to find them important enough to keep? Darwin attacks this question a little more effectively, I feel, than he did in the latter segment. His argument in this case seems stronger, perhaps because he has more scientific evidence than he had at his disposal on other topics.

Darwin uses the example of the neuter worker ants. His reasoning for the neuter gender, on the surface, is much the same as the reasoning for all of the arguments presented to him. He says that he can find neuter insects explicable if "...such insects had been social, and it had been profitable to the community that a number should have been annually born capable of work, but incapable of procreation [He] can see no very great difficulty in this being affected by natural selection." (p. 236) This is not the end for this argument though. Darwin then puts forth the question, that if a creature is neuter, how does it pass along to its progeny the variations it has acquired. The easy and correct answer is that it doesn't. Then how can this be answered