What Is Evolution?

In order to understand the theme for this month, "Evolution In Action," it is necessary to understand just what evolution is.

The scientific Theory of Evolution states that species change over time. The forms that the changes take are shaped by the process discovered by Charles Darwin known as Natural Selection.

Charles Darwin's book, On The Origin Of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, later shortened simply to On The Origin Of Species, is not a myth, but rather a scientific treatise outlining the theory he had postulated, based on scientific observations of finches and other fauna of the Galapagos Islands while Charles sailed with The Beagle.

On The Origin Of Species proposed that evolution worked on the principle that a hereditary trait which was an adaptation to a changing environment allowed the species possessing that adaptation to thrive for longer in that environment than others of that species that did not possess that same adaptation; and that the adaptation permitted the adapted organisms long enough to breed and thus pass on that adaptation to their offspring, who would be better equipped to survive in that environment, thus ensuring that the adaptation would eventually spread throughout the population.

Consider a species known as the pepper moth. For centuries, its wings were mostly white, with a few darker-winged individuals born here and there. Against a tree with a lighter bark, the darker-winged moths were more readily spotted and picked off by birds.

But then Mankind and industrialisation began altering the environment, and the carbon deposition from the coal-powered factories began turning the bark of the trees darker. Under those circumstances, moths with the darker wings tended to survive long enough to pass on their mutation to their offspring, whereas those with the lighter wings now became the easier prey. Within a few generations, the species that adapted to dark wings was the variety which prevailed, with lighter wings being present once in a while in short-lived individuals.

The key to evolution, as discovered long after Darwin's death, lay in the genetic code, the structure of the DNA ribosome sequence and in mutation. Through random mutation, individuals are born to their parents with inherited characteristics from both, but also on occasion with mutations which came from neither parent, but which originate from within the organism's own genome itself.

The Theory of Evolution By Means of Natural Selection proposes that  these mutations can either be a benefit, or a liability, to an individual; but that on the whole, the generation with the species possessing that genetic adaptation is the one which will prevail to propagate that adaptation.

And that is basically it. Nothing in there about creatures evolving in mid-stride. You've got what you've got, and if your adaptation allows you to survive long enough to breed, if is your adaptation which will be passed on through the generations. Nothing more than that.