What is Evolution?

Therion Ware wishes to note that he's not really very interested in evolution, but finds it necessary to have a section on it in order to counter certain creationist claims. If you spot any errors, feel free to mail Therion.

Evolution is the process of genetic transformations of populations through time, resulting from genetic variation and the subsequent impact of the environment on rates of reproductive success. (Oxford Dictionary of Philosophy).

We might also note what evolution is not, which is to say evolution is not evolutionism - the discredited late 19th and early 20th century quasi-political doctrine associating the changes of evolution with a progressive view of social change, positive attitudes towards competition, and war, justification of inequalities of power, and so forth.

Evolution is a blind process. This is to say that the process of genetic transformation cannot be said to have an end "in mind"; it is not inevitable that, given a single celled organism and 3.1 billion years (on a planet 1.4 billion years old) years orbiting a fairly typical star at an average distance of 93,000,000 miles, one will end up with self-aware, intelligent entities who are capable of making and using tools that call themselves "human beings" (or similar).

Evolution does not account for the origin of life, nor does it pretend to do so. It does account for the mechanisms by which life, once existent, adapts to its environment. The origin of life itself remains something of a mystery, but one that is ameanable to scientific investigation. The process that gave rise to life is frequently refered to, incorrectly, as "abiogenesis". The correct terms is biopoiesis (abiogenesis, also known as spontaneous generation implies the spontaneous creation of complex, higher, organisms, even animals, from non-living matter. The notion was discredited by 18^th century, and fully laid to rest by Pasteur in the 19^th century ).

When considering the relationship of biopoiesys to evolution one should, I feel, note the opinion of Darwin who said of the matter: "It is mere rubbish thinking at present of the origin of life; one might as well think of the origin of matter".

Darwin's theory of natural selection is summarised in the Origin of Species as follows:

As many more individuals are produced than can possibly survive, there must in every case be a struggle for existence, either one individual with another of the same species, or with the individuals of distinct species, or with the physical conditions of life. . . . Can it, then, be thought improbable, seeing that variations useful to man have undoubtedly occurred, that other variations useful in some way to each being in the great and complex battle of life, should sometimes occur in the course of thousands of generations? If such do occur, can we doubt (remembering that many more individuals are born than can possibly survive) that individuals having any advantage, however slight, over others, would have the best chance of surviving and of procreating their kind? On the other hand, we may feel sure that any variation in the least degree injurious would be rigidly destroyed. This preservation of favourable variations and the rejection of injurious variations, I call Natural Selection.

Critics point out that [...] a scientific theory should have predictive power, [...]. Consider the theory that dinosaurs evolved into birds. The dinosaurs are dead and gone. Either they evolved into birds or they did not. The theory predicts that the paleontological record will disclose further links between dinosaurs and birds. If it does, the theory will survive . If it does not, thc theory will not. The theory thus has predictive power, though what it predicts is not the future of dinosaurs and birds but the future course of our knowledge about them.

So although the theory of evolution cannot predict the nature of future adaptations in response to environmental pressure, it can predict what we will discover about those adaptations.