Trying to understand counterintuitive sexual parts and habits follows in the best of scientific traditions. As Charles Darwin worked on evolution, he pondered male phenomena that looked useless, or even harmful, for surviving. Outsized horns on male beetles puzzled him, as did male birds with gorgeous plumage.

Out of this consternation came his insight into a process he called sexual selection, which he distinguished from natural selection. There may be survival of the fittest, but there’s also survival of the sexiest.

“The sight of a feather in a peacock’s tail, whenever I gaze at it, makes me sick!” Darwin wrote in a letter to the botanist Asa Gray, albeit in a whimsical paragraph. Nauseated or not, Darwin was willing to step beyond survival of the fittest.

He devoted a few pages in the Origin to introduce sexual selection as a sort of wild-oats younger brother of natural selection. Sexual selection, as Darwin formulated it in the sixth edition of Origin, depends “not on the struggle for existence in relation to other organic beings or to external conditions, but on a struggle between the individuals of one sex, generally the males, for possession of the other.”

<i>Yet the most dramatic examples of the power of evolutionary theory may come from the strange and ugly stuff — biology that seems too dumb to have been designed.</i>

That part gave me a good laugh. But also, so true! If all of this was intentionally designed, it was done so by a total idiot. So there's your choice folks. The beauty of life trying to find its way, or a moron designer. I know which one I'd rather have.

Darwin never refers to "survival of the fittest"; instead, he talks about species adapting to suit their environment, or ecological niche. To Darwin, "fittest" meant "best adapted".

The idea that the "fittest" (i.e., strongest) survived (and, indeed the phrase "survival of the fittest") originated with Herbert Spencer, a Lamarckian philosopher whose ideas gave rise to what eventually came to be known as "social Darwinism" but which had no connection to Darwin himself.

Lamarck was a French biologist whose theories included the notion that an acquired characteristic could be inherited. There were other aspects to his work, but the inheritance of acquired traits came to be the most closely identified with his name.

It seems that the 'logic' of evolution is sometimes counter intuitive to rational consideration. It is both ingenious and idiotic at times. Yet we should remember that these adjectives are related to our kind of linear reasoning. We find it so incredible that evolution does not have a specific fixed goal that we all the time try to describe evolutionary processes in terms of goals that we imagine.