You have three different questions here. Regarding the first question, I would say that the members of our culture have simply removed ourselves from the conditions under which evolution takes place; this is the whole point of taking our lives into our own hands. To say that I “proclaimed” it suggests that the statement is to be taken on faith. I would say rather that I merely asserted it, and presented grounds for the assertion, which will be examined in greater detail below.
Regarding the second question, it’s entirely possible for one “section” of a species to evolve separately from other sections—if the conditions under which the one section live become different from the conditions under which the others live. An excellent example of this can be found in the very distinctive physical differences that developed among Leaver peoples living under the conditions of the far north—the Eskimos.
Over time (hundreds or thousands of years), their bodies adapted to two significantly different conditions from the rest of humanity: severe cold and the absence of nearly all forms of edible fruits and vegetables, leaving them with a diet that consisted almost entirely of meat. By contrast, immigrants to Alaska from the lower United States do not have to adapt to these conditions, because they bring with them central heating and supermarkets supplied with food from the south. This illustrates very clearly why these Taker immigrants are not evolving: they don’t need to; they’re shielding themselves from the conditions under which evolution takes place.
I believe the answer to the second question also answers the third. The Eskimos exemplify how Leaver peoples evolved, and their physical differences from peoples of the south constitute proof of that evolution.
The questioner had a follow-up query: Would a reasonable alternative hypothesis to your assertion that people in the Taker culture have stopped evolving be that they do continue to evolve but not how they would have if they had adopted a Leaver culture? I cannot think of an example to offer, but the idea is that Takers continue to evolve in a way that perhaps is not beneficial to them or in a way that reflects their Taker culture.
My reply: Evolution is not an ongoing, inevitable process, like, say, aging. It’s a response to new conditions that favor some individuals (who survive to reproduce) over others (who do not survive to reproduce). I can see no conditions at work today that would have this effect on humans. When (and if) the combined effects of our impact on the environment finally combine to cause a general ecological collapse, there will be no time for Homo Sapiens to adapt (just as there was no time for Tyrannosaurus or Triceratops to adapt).
updated: 09 Feb 2006