SINGULAR ORIGIN

If a species has a unique trait with seemingly broad, cross-niche application, why is that trait unique? Why didn’t it evolve in other species? I guess some traits require a certain kind of substrate to act upon, sort of like the activation energy of an endothermic chemical reaction. So even if a trait does have broad applicability, not every species has the building blocks to develop it.

I was thinking about this while reading this Times magazine article on the evolution of our fat heads, and it occurred to me that intelligence (or some of its manifestations, like problem solving or tool use) would be useful in all walks of life, and that there would be constant selective pressure in that direction. Something without that kind of broad applicability might be fins. Humans aren’t adapted for aquatic living, so fins are not adaptive. However, intelligence could benefit a fish, in hunting, avoiding predators, etc.

The article is kind of awful, describing a recent realization that the gene controlling jaw muscle size diverged in the human and chimp lineages at about the same time brain cavity size did, and going on to point out what a hit to the human ego it is to have a key factor in our intelligence due to a seemingly random event, or at least an event that had little to do with selection of intelligence. Perhaps the author doesn’t realize that the genetic variability upon which natural selection operates is created by flukes and shuffling like mutation and recombination.

Anyway, I was thinking one could study similar traits that could benefit species occupying a variety of niches, traits that are little less vague than intelligence. Something non-cognitive, like some component of the immune system, or nitrogen fixation or something. Probably not. The problem with blog-style publishing is there’s usually no one to tell you how stupid you sound.