of natural selection was the basis of Darwinism. This assertion
is stressed even in the title of the book in which Darwin
proposed his theory: The Origin of Species, by means of
Natural selection is based on the assumption
that in nature there is a constant struggle for survival.
It favors organisms with traits that best enable them to cope
with pressures exerted by the environment. At the end of this
struggle, the strongest ones, the ones most suited to natural
conditions, survive. For example, in a herd of deer under
threat from predators, those individuals that can run fastest
will naturally survive. As a consequence, the herd of deer
will eventually consist of only fast-running individuals.
However, no matter how long this process goes
on, it will not transform those deer into another species.
The weak deer are eliminated, the strong survive, but, since
no alteration in their genetic data takes place, no transformation
of a species occurs. Despite the continuous processes of selection,
deer continue to exist as deer.
The deer example is true for
all species. In any population, natural selection only eliminates
those weak, or unsuited individuals who are unable to adapt
to the natural conditions in their habitat. It does not produce
new species, new genetic information, or new organs. That
is, it cannot cause anything to evolve. Darwin, too, accepted
this fact, stating that "Natural selection can do
nothing until favourable individual differences or variations
occur."7 That is why neo-Darwinism
had to add the mutation mechanism as a factor altering genetic
information to the concept of natural selection.
We will deal with mutations next. But before
proceeding, we need to further examine the concept of natural
selection in order to see the contradictions inherent in it.
7 Charles Darwin, The
Origin of Species by Means of Natural Selection, The
Modern Library, New York, p. 127. (emphasis added)