## Metadata - Author: [[Nicholas Wade]] - Full Title: Before the Dawn - Category: #books ## Highlights - The head and body louse closely resemble each other except the body louse is larger and has claws specialized for grasping material, not shafts of hair. Stoneking realized that he could date the invention of clothing if he could only figure out from variations in lice DNA the time at which the body louse began to evolve from the head louse. ([Location 99](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=99)) - The branch point at which the body louse first evolved from the head louse turned out to be around 72,000 years ago, give or take several thousand years either way.2 Assuming the body louse evolved almost immediately after its new niche was available to it, then people first addressed their nakedness only in the most recent stage of their evolutionary history. It was about this time, or a few thousand years later, that people perfected language and broke out of Africa to colonize the rest of the world. It seems they had decided to get dressed for the occasion. ([Location 104](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=104)) - Despite the serious lack of fossil evidence, much can be inferred about the joint human-chimp ancestor. Its population numbered somewhere between 50,000 and 100,000 breeding individuals, according to genetic calculations.6 ([Location 273](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=273)) - Note: seems to me there is circular reasoning here. population size and time of divergence are used to support each other - Their populations were small, as judged by the archaeologists’ standard people-meter, the tortoise test. (People catch large tortoises first, then smaller ones. Tortoises are so slow to replace themselves that the size of a human settlement can be judged by whether the tortoise bones are large, indicating a sparse human population, or small, meaning rather more mouths to feed.) ([Location 509](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=509)) - It was obviously a genetic change, not a cultural one, that endowed the australopithecines with upright stature 4.4 million years ago. It was a suite of genetic changes 2.5 million years ago that remodeled the australopithecines into Homo habilis with its larger brain and tool-making ability. A third far-reaching genetic makeover 1.7 million years ago reshaped habilis into the more humanlike erectus and caused a behavioral transition from male and female hierarchies to the pair bond system. And it must have required a fourth genetic revolution, Klein believes, to make possible the emergence of behaviorally modern humans 50,000 years ago. ([Location 543](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=543)) - In an unusual alliance, the animal communication experts Marc Hauser and Tecumseh Fitch recently joined with the linguist Noam Chomsky to propose that the human capacity for syntax might have evolved out of an animal brain module designed for some other purpose, such as navigation.38 Their argument is that the essential feature of language is recursion, the ability to embed one phrase inside another in an indefinitely long chain. Recursion may also be a feature of faculties like navigation that require an animal to remember how to get from A to D, with an excursion to B and C if the way is blocked. If the genes that specify the brain’s navigation module were accidentally duplicated, the spare set would be free to evolve and perhaps acquire the function of encoding thought into language. ([Location 638](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=638)) - Although the San’s mitochondrial L1 lineage makes them only cousins to the people who left Africa for Asia (a sub-branch of mitochondrial L3), they bear some striking physical resemblances to Asian populations, suggesting that both lineages may have inherited these features from the ancestral human population. Many Khoisan speakers have yellowish skin, the epicanthic folds above the eyes that give some Asian eyes their characteristic shape, shovel-shaped incisors (front teeth hollowed out on the tongue side of the mouth, found commonly in Asians and Native Americans), and mongoloid spots—a bluish mark on the lower back of young infants. The !Kung San themselves apparently recognize this similarity since they assign Asians to the category of Real People like themselves, as distinct from !ohm, the category of non-San Africans and Europeans.77 ([Location 1125](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=1125)) - Their hunting bows are lightweight because they poison their arrow shafts with a lethal toxin. They obtain it from the pupae of any of three species of chrysomelid beetle that they dig up from beneath the bushes where the larvae have fed. The pupae stay in arrested development for several months, enabling hunters to carry them around and freshen up the toxicity of their arrows when needed. A well placed arrow will kill a 200-kilogram antelope in 6 to 24 hours.78 In the laboratory, 25 trillionths of a gram of the arrow poison extracted from one of the beetle species, Diamphidia nigro-ornata, is enough to kill a mouse.79 ([Location 1135](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=1135)) - Portability imbues !Kung life so thoroughly that it affects even the spacing of children. A woman can carry one child easily along with all her possessions, but two are a burden. !Kung women tend not to have a second child until the first can walk well. ([Location 1147](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=1147)) - Perhaps because a woman must invest so much care and labor in raising a child, she examines her newborn carefully for signs of defects. “If it is deformed, it is the mother’s duty to smother it,” writes the demographer Nancy Howell.81 Infanticide is not the same as murder, in the !Kung’s view, because life begins not with birth but when the baby is taken back to camp, given a name and accepted as a Real Person. “Before that time, infanticide is part of the mother’s prerogatives and responsibilities, culturally prescribed for birth defects and for one of each set of twins born,” Howell says. ([Location 1151](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=1151)) - After some differences of opinion, geneticists now seem to agree that the trees drawn on the basis of the Y chromosome and of mitochondrial DNA both point to a single exodus from Africa. ([Location 1273](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=1273)) - Presumably men of the M168 lineage accompanied the M and N lineage women as they and their descendants migrated from Africa to India. ([Location 1340](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=1340)) - In terms of evolution’s overall process, drift is the counterpart to mutation. Mutation constantly injects novelty into the genome, and in each generation drift sweeps novelty away. Natural selection draws on this flux, using it to keep each species adapted to the changing environment. ([Location 1352](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=1352)) - By whichever route the first humans left Africa, India seems to have been their first major stopping point, because it is there that are found the first di versifications, outside Africa, of the mitochondrial and Y chromosome trees. ([Location 1368](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=1368)) - genetic dates, though always interesting, depend on many assumptions that may not be realistic, and the dates derived by archaeologists are considerably more reliable. ([Location 1401](https://readwise.io/to_kindle?action=open&asin=B000PDYVRA&location=1401))