Steven Pinker -- How the Mind Works - Hampshire High Italian ...

204 J HOW THE MIND WORKStor said it was like finding a Pontiac in Leonardo da Vinci's attic. But asarcheologists are starting to explore this continental attic and date itscontents, they are finding more and more Pontiacs: fine stone blades,decorated tools, useless but colorful minerals transported hundreds ofmiles.Third, the mitochondrial Eve of 200,000 to 100,000 years ago wasnot a party to any evolutionary event. Contrary to some fantastic misunderstandings,she did not undergo some mutation that left her descendantssmarter or more talkative or less brutish. Nor did she mark the endof human evolution. She is merely a mathematical necessity: the mostrecent common ancestor of all living people along the female-femalefemaleline of great-great-. . .-great-grandmothers. For all the definitionsays, Eve could have been a fish.Eve, of course, turned out to be not a fish but an African hominid.Why would anyone assume that she was a special hominid, or even thatshe lived in special times? One reason is that she made many other timesand places non-special. If twentieth-century Europeans' and Asians'mDNA is a variant of 200,000-year-old African mDNA, they must bedescendants of an African population at the time. Eve's contemporaryEuropeans and Asians left no mDNA in today's Europeans and Asians,and thus presumably were not their ancestors (at least—and this is a bigproviso—not their all-maternal-line ancestors).But that says nothing about evolution's having stopped with Eve. Wecan assume that most evolution was done with by the time the ancestorsof the modern races separated and stopped exchanging genes, sincetoday we are birds of a feather. But that did not happen as soon as Evebreathed her last. The diaspora of the races, and the end of significanthuman evolution, must have occurred much later. Eve is not Our mostrecent common ancestor, only our most recent common ancestor in theall-maternal line. The most recent common ancestor along a mixed-sexline of descendants lived much later. You and a first cousin share anancestor of just two generations ago, your common grandmother orgrandfather. But in looking for a shared all-female-line ancestor (yourmother's mother's mother, and so on), then except for one kind of cousin(the child of your mother's sister), there's almost no limit to how far backyou might have to go. So if someone were to guess the degree of relatednessbetween you and your cousin based on your most recent ancestor,he would say you were closely related. But if he could check only themost recent all-female-line ancestor, he might guess that you are not