We and our genes:
There is, and for the foreseeable will be, an abiding interest in just where human genes came from. Out of Africa of course remains the standard version, but things get more complex (J. R. Stewart and C .B. Stringer Human Evolution Out of Africa: the Role of Refugia in Climate Change SCIENCE vol. 335 no. 6074 Mach 16 page 1317) one that exodus has been taken into account. The key concept in the article is that when an ice age romps upon us some living things, like oak trees, are adversely reflected and their range contracts into the remaining habitable zones called “refugia.” At the same time some living things, like polar bears, find broader horizons and their range expands.
This cycle produces two kinds of opportunity. For the refugee populations the general isolation and smaller and therefore more uniform environment opens the door to speciation or at least a movement in that direction. The other kind of opportunity results from the fact that these refugia can be distinguished geographically and the time of their function as sole or one of few survivable locations can be compared with the known timing of the climate change.
This makes it possible to do more than simply speculate about where and when human species, such as the Neanderthals, evolved and why. Evidence can be brought to bear. It seems to me that the inherent limitations of population size must have an effect on this. I know it exists. Nobody writing about it seems to know. So if I know something that they don’t I should be able to account for evidence that baffles them.
Should be but amn’t: tantalizing as the prospect is, I cannot say, “Aha, the secret is that your refuge is in fact marginally habitable itself. That keeps the population small and thus reproductively vigorous.” That would be consistent with the early appearance of civilizations in unpromising places. Agriculture on land bordering desert long preceded agriculture in the Elysian fields of France. But I cannot think of any evidence on the ground that would support my contention.
One statement did strike me. They made the remark (and referenced it: M. Hofreiter and I. Barnes BMC Biol. 8, 46 (2010)) that extinctions at the subspecies level are much more common than had been thought. Well yes, I could have told you that. In fact I think I have told you that. Humans with our vigor and our heedless eagerness for sex and novelty regularly form social groups too large to be viable and suffer nature’s chastisement. That’s why fertility symbols are among the most common ancient artifacts and Christianity, which is a fertility cult among other things, is the most popular religion in the world today. People understand that babies are important, just not how to make them (beyond the mechanics of intercourse and some very expensive medical interventions.)
While on the subject of the ancient adventures of our genes, there is another paper. (The Nature of Man ECONOMIST vol. 404 no. 8801 September 8, 2012 page 77) It has been found that certain genes are more conserved than others. No surprise there. One can think of minor changes that would have little effect on the number of offspring one may have. Others that are more vital to reproduction, or survival until reproduction is possible, if they change things for the first are eliminated rather efficiently by selection. So it is of interest to know what genes are conserved in humans that are less vigorously conserved in other primates. (Of course modern preference is to emphasize the control mechanisms for genes, not just the genes themselves, but it makes no difference for the present point.) It turns out that the genes that make us human are the ones for color vision and nerve cell growth.
Since humans have long lived in societies with cultures, the ability to adapt to the local culture is of great importance. Flushing, pallor, decorations and who knows what all can be used as signaling clues within a culture. So the value of color vision is not a surprise. I find it a little strange that nerve cell growth is something of great moment for selection in humans in contrast with less importance for other primates. After all, we are so much smarter. But again the function of the brain in making ones efforts dovetail with those of ones companions may take more thinking and deciding how best to get a grub out of a rotten log.
So we are not only smarter, we work our brains harder.
That flabbergasts me. Here I try to tell any who will hearken something of extreme importance and they just don’t “get it.”
This isn’t hard. The game cat’s cradle, now that’s hard. The proof that there is no pair of numbers that can be divided to give the square root of 2, that’s one that takes whole minutes to clarify. Bell’s Inequality, demonstrating that the characteristics of a photon do not in fact exist in their entirety until the photon is measured or otherwise interacts with classical matter, I cannot even remember the proof from one day to the next; that one’s hard. Wearing a square rigger … oops, time for some definitions, when a sailing ship turns so that the wind crosses the bow it is called a “tack.” When turning so that the wind crosses the stern it is a “jibe” in a fore-and-aft rigger but a “wear” in a square rigger … The way you wear basically is that you reduce effective sail area toward the stern of the ship, let the sails forward bring the bow downwind and then restore the effect of the stern-most sails and start out on a new tack. You must do this in very light or very heavy wind. If the wind is perfect it is practicable to turn through the eye of the wind. The whole maneuver of wearing is rather complex. http://www.ehow.com/how_5747341_tack-square-rigger.html
But people can understand it. Oh, well. Some day perhaps.
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