" We meet with this admission in the writings of almost every
experienced naturalist; or, as Milne Edwards has well expressed it, "Nature
is prodigal in variety, but niggard in innovation." Why, on the theory of
Creation, should there be so much variety and so little real novelty? Why
should all the parts and organs of many independent beings, each supposed
to have been separately created for its own proper place in nature, be so
commonly linked together by graduated steps? Why should not Nature take a
sudden leap from structure to structure? On the theory of natural
selection, we can clearly understand why she should not; for natural
selection acts only by taking advantage of slight successive variations;
she can never take a great and sudden leap, but must advance by the short
and sure, though slow steps.
ORGANS OF LITTLE APPARENT IMPORTANCE, AS AFFECTED BY NATURAL SELECTION.
As natural selection acts by life and death, by the survival of the
fittest, and by the destruction of the less well-fitted individuals, I have
sometimes felt great difficulty in understanding the origin or formation of
parts of little importance; almost as great, though of a very different
kind, as in the case of the most perfect and complex organs.
In the first place, we are much too ignorant in regard to the whole economy
of any one organic being to say what slight modifications would be of
importance or not.
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