Monday, January 3, 2011

Origin of Species by Charles Darwin

Biologists face similar societal successes and dilemmas as physicists and chemists. Biologists must also deal with ethical and moral issues resulting from the application of their basic research. There is no doubt that tremendous discoveries made in biology have been wonderfully beneficial to society; however, some have a downside just as atomic weapons, radiation, nuclear waste, and chemicals which have harmful effects or pollute the environment.

Biologists and biochemists are responsible for breakthroughs in fields of cellular biology, cancer, stem cell and cloning research, etc. Life spans have dramatically increased; cures for new diseases are continually being discovered, and infant mortality has dropped over the years. These are a few of the hundreds of examples of the benefits to society due to the biological sciences. As with science in general, biological issues must also address moral and ethical consequences that are potentially detrimental. Many political, ethical, and even religious issues today are related to biological science and research. Human cloning, using embryo tissue for stem cells, the evolution debate, and genetically engineered foods are examples that result in science affecting society with both positive and negative potential.

No issue better exemplifies the complex relationship between the science of biology and
society than evolution. Darwin’s theory is one of the basic tenants of the biological sciences. The theory of evolution is defined in The Origin of Species and is one of the fundamental building blocks upon which the credibility of biology is built. Darwin’s book, On the Origin of Species by Means of Natural Selection, or the Preservation of Favored Races in the Struggle for Life published in 1859, is considered one of the major books of Western civilization.

Controversy has surrounded Charles Darwin’s theory of evolution from its writing and has continued for almost one and a half centuries. His seminal work has been opposed, supported, damned, made into movies, debated, decided via legal battle, questioned, believed, and little understood by many. The fact that Darwin’s book seems more easily readable to the general public than a physics equation, chemical reaction, or math-based theorem, is deceiving because of Darwin’s complex discussions. Even Darwin struggled to clearly present his theory as is noted by his numerous changes in the six editions of the book. He writes:
That many and grave objections may be advanced against the theory of descent with modification through natural selection, I do not deny. I have endeavored to give them full force. Nothing at first can appear more difficult to believe than that the more complex organs and instincts should have been perfected, not by means superior to, though analogous with, human reason, but by the accumulation of innumerable slight variations, each good for the individual possessor. Nevertheless, this difficulty, though appearing to our imagination insuperably great, cannot be considered real if we admit the following propositions, namely … The truth of these propositions cannot, I think, be disputed. (page 362)

Darwin’s truth was questioned from the beginning by naturalists during his time and is still being questioned by many people today. Many argue the theory of evolution is just a theory! Is this the start of a movement that could potentially result in questioning the validity of science in general? An entire culture of anti-evolutionists has ‘evolved’ to refute Darwin advocating creationism and/or intelligent design.

Evolution has been addressed recently by the legal system in Dover, Pennsylvania to determine if intelligent design should be taught in high school courses along with the theory of evolution. The school board of Dover attempted to make the pro intelligent design text, Of Pandas and People part of the high school curriculum. In Kansas the school system pushed for similar treatment of both ideas – evolution and intelligent design - in the schools. Proponents of intelligent design claim that their theory has as much relevance as the theory of evolution. Islamic scholar, Harun Yahya (pen name), in his book, The Evolution Deceit, presents arguments opposing evolution. His argument is solely based on creationism. The editor of American Spectator, Tom Bethell agrees with anti-evolutionists in his writing “By Chance or By Design”. If you Google books that are anti-evolution scores of texts will appear with little searching. Oppositely, books like Evolution vs. Creationism by Eugenie Scott and The Blind Watchmaker by Richard Dawkins as well as many other pro-evolution texts can easily be found. It is ubiquitously stated that approximately half of the population does not believe that the theory of evolution is accurate and factual.

This section of the course will begin with the main tenants of Darwin’s theory of evolution from The Origin of Species in his own words, and in much detail, to present an accurate a picture as possible. The reader must realize that volumes and volumes have been written on this topic so note that the effort here is only to give an introduction to this controversial topic. Darwin begins to define his theory based on what can be readily observed via domesticated breeding of animals. He writes:
May not those naturalists who, knowing far less of the laws of inheritance than does the breeder, and knowing no more than he does of the intermediate links in the long lines of descent, yet admit that many of our domestic races have descended from the same parents – may they not learn a lesson of caution, when they deride the idea of a species in a state of nature being lineal descendants of other species? (page 34)

In discussing the manner breeders use by avoiding cross breeding to obtain a good pedigree Darwin writes:
If selection consisted merely in separating some very distinct variety, and breeding from it, the principle would be so obvious as hardly to be worth notice; but its importance consists in the great effect produced by the accumulation in one direction, during successive generations, of differences absolutely inappreciable by and uneducated eye… (page 36)

Darwin ends his discussion of the chapter, Variation under Domestication,by stating:
Over all these causes of Change I am convinced that the accumulative action of Selection, whether applied methodically and more quickly, or unconsciously and more slowly, but more efficiently, is by far the predominant Power. (page 45)

In discussing his chapter, Variation under Nature, he writes:
Hence, it is the most flourishing, or, as they may be called, the dominant species, - those which range widely over the world, are the most diffused in their own country, and are the most numerous in individuals, - which oftenest produce well- marked varieties, or, as I consider them, incipient species. And this, perhaps, might have been anticipated; for, as varieties, in order to become in any degree permanent, necessarily have to struggle with the other inhabitants of the country, the species which are already dominant will be the most likely to yield offspring which, though in some degree slight degree modified, will still inherit those advantages that enable their parents to become dominant over their compatriots. (page 53)

Ending the discussion of natural variation Darwin writes:
We have, also, seen that it is the most flourishing and dominant species of the larger genera which on an average vary most; and varieties, as we shall hereafter see, tend to become converted into new and distinct species. The larger genera thus tend to become larger; and throughout nature the forms of life which are now dominant then to become more dominant by leaving many modified and dominant descendants. (page 57-58)

Darwin discusses the struggle to exist in terms of dependence, survival, and leaving progeny. He writes:
A corollary of the highest importance may be deduced from the foregoing remarks, namely, that the structure of every organic being is related, in the most essential yet often hidden manner, to that of all other organic beings, with which it comes into competition for food or residence, or from which it has to escape, or on which it preys… that each organic being is striving to increase at a geometrical ratio… and that the vigorous, the healthy, and the happy survive and multiply.(page 72-73)

Darwin called the “preservation of favorable variations and the rejection of injurious variations,” Natural Selection. (page 75) The best adapted to their environment and most vigorous survive. He writes:
Natural selection, also, leads to divergence of character; for more living beings can be supported on the same area the more they diverge in structure, habits, and constitution, of which we see proof by looking at the inhabitants of any small spot or at naturalized productions… Natural selection leads to divergence of character and to much extinction of the less improved and intermediate forms of life. (page 112)

Darwin uses his design of the Tree of Life to show the progression of natural selection with many branches representing a long succession of extinct species, known to us only in the fossil state, while other branches grow, bear other branches, and show the current surviving species.

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