The Science of Evolution

Were We Bound To Evolve? --
The Role of Random and Non-Random Factors in Evolution

While human beings are one particular result of billions of years of step-wise biological evolution (and clearly not the special and independent Creation of a supernatural force or god), it is not the case that evolution was inevitably "bound" to "lead up to" the emergence of the human species. Populations of living organisms evolve through a complex combination and interplay of both "chance" and "necessity": first of all, random ("chance") factors such as mutations, recombinations and genetic drift, lead to a continual re-shuffling of the deck of cards which makes up the total genetic variation in a population and which serves as the raw material of evolutionary change; but, then, on the basis of that randomly produced variation, natural selection proceeds to very much non-randomly sort out some of the resulting features of organisms in relation to the demands and challenges of a given external environment. This process can proceed for a time in a certain specific "direction," as when populations of organisms are becoming increasingly "adapted" to a certain set of environmental conditions. But it is important to realize that not all evolutionary modifications represent adaptations, that there are no permanent and "set" directions in the evolution of life, and that evolutionary trends and directions can change course (or even completely reverse themselves) as conditions change.

The Creationists like to say that evolutionists believe that all the different life-forms, including human beings, came about "purely by accident." But all this shows is that they don't understand that evolution comes about through a combination of both random and non-random factors: in the evolution of human beings or any other species, natural selection non-randomly "favored" certain step-by-step modifications (which happened to have emerged on the basis of random variation) whenever such a modification conferred a distinct reproductive advantage on individuals which had that new feature. This is the part of the evolutionary process which is not "accidental" (though it still doesn't involve any supernatural guidance or selection of any sort). But then again there were never any guarantees that any particular forms of genetic variation would arise in the first place; that they would not be extinguished almost as soon as they had emerged; or even that a given species as a whole would avoid extinction in a given external environment. In short, the evolution of human beings or any other life-form is not just the result of a series of "accidents" (though accidents do play an important role in evolution), but neither did it require, or involve, the intervention of any outside supernatural forces.

And, while human beings are definitely the product of natural biological evolution, evolution could just as easily not have led to the emergence of human beings at all!

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