The only additional comment I would make is due to my stress over the use of the term ‘adaptation’ in discussions on evolution. I feel that folk are misled by its use—where my experience suggests that many interpret it to mean that critters change voluntarily. If indeed there are scientists who believe that, I’m anxious to hear evidence.

Genetic mutations occurring over time, even with a periodicity, have been detected or measured with techniques I’m ignorant of.
If we accept this, and I do, then my view is that the prevalence of different anatomical or physiological [disposition, psychological?]* features of people (many critters) in any given region of the planet are due to the success, i.e., the advantage that those changes rendered for the members of the group (over generations) in that environment and or in mate selection. [I guess I'm just a dyed-in-the-wool 'survival of the fittest' fan.]

During conversations I’ve had with people, I get the distinct impression that many ‘understand’ evolution to be a choice made by individuals—that when suddenly faced with or move to a different environment, they simply decide to “change” [adapt] to the new circumstances. As I said, I’d love to see evidence of this.

I envision migrations to new areas, across dozens of generations, where some individuals have a greater tolerance for the new environmental circumstances or demands. They survive. They live longer and foster ‘like’ individuals who equally survive.
Throughout this generational journey, those ill-suited for the different environment(s) die off early and breed less, resulting in fewer and fewer of the group members over time whose makeup was better suited to the environment they left behind.

It becomes a numbers or statistical issue. Mutations occur in some offspring, likely a very small percentage, who are even better suited for the new ‘world’ the group lives in, while other mutations are less suited than even those members not reflecting any mutations. The less suited individuals are less successful. Those less suited are less attractive to—are possibly even prohibited from—mating. They reproduce less or not at all. They are less able to ‘keep up’ with their daily needs and probably succumb; they are possibly even shunned by the group for a variety of reasons that one might imagine.
Those better-suited mutations accumulatively become the ‘breeding’ foundation of the group in the new environment, surpassing, by their success, even the genetic lineage who simply had a better tolerance in the early days.

Over thousands of years, the resulting ‘new’ group members are the product of an evolution—produced through the aid of mutations—fine-tuned to their new environment, notwithstanding ‘throwbacks’ in the chromosomal ‘crap shoot’ of reproduction. They did not ‘do it’ to themselves—consciously—its really been done to them. To echo the father of this topic, they have been selected naturally to their environment.

Forgive me if I’m sounding didactic. It’s what—’adaptation’ and my sense of folks’ interpretation of its use in regard to evolution—does to me!

* If you have not seen it, try to view, the next time it’s aired, Dogs That Changed the World: Part One, “The Rise of the Dog”. The 40 year Russian experiment with Siberian Foxes is a revelation. One out of 100 fox offspring had a docile mood compared to the others. The premise is that prehistoric man may have encountered a similar phenomenon exemplified in a wolf or two which may have been the precursors of dogs. Great film! And, great insight to the possibilities within genetic variation!

It provokes my thinking about personality—mood—disposition… whatever, in primates and what genetic variation research could be pursued along the line of this idea. A hint lies with the dramatic difference between common Chimpanzees and Bonobos, the latter of which, in contrast with the former, would rather make love than war. Most likely another trait somehow dictated by natural selection, it is interesting that unlike the common Chimpanzee’s social order, Bonobos are more matriarchically ordered….

Cheers,
Paul