📖Sapiens: A Brief History of Humankind

Harari, Yuval
  • p.4 species = mate (sexual attraction) + fertile offspring. species are basically DNA pools
  • p.4 genus (pl. genera) — species evolved from common ancestor
  • p.4 biologists name organism in two parts: genus + species. Homo (genus) sapiens (species)
  • p.4 genera are grouped into families
  • p.5 6mln years ago — last common ancestor with chimpanzees
  • p.6 homo erectus has been surviving for 2mln years. sapiens are only 200k years old and will unlikely survive for that long
  • p.7 homo floresiensis underwent the process of dwarfing. max height ~1m, weight 25kg
  • p.8 homo brains are large compared to other animals

    • drain of energy. brain is only 2-3% weight but consumes 25% energy at rest (comp to only 8% for other apes)

      • more time in search of food
      • muscles atrophied (diverting energy to neurons)
  • p.9 we don’t know why evolution favored bigger brains
  • p.10 Homo paid for upright position with backpains and stiff necks
  • p.10 upright position needs smaller hips, restricting the birth canal. At the same time while brains got bigger. That resulted in more women death during birth. Those who gave birth prematurely had more chances to survive and give produce more offspring, so evolution favored early birth

    • human babies require several years of caring. and one woman is unlikely to provide enough food, so social structures have evolved
  • p.10 “it takes a tribe to raise a human”
  • p.11 some researchers believe that marrow (костный мозг) was our original niche. (Cracking bones open with stone to get to the marrow)
  • p.11-12 humans used to be in the middle of the food chain and only recently jumped to the top (and very fast)

  • p.13 because of cooking, humans need shorter intestines. Shorter intestines drain less energy and allow more energy for even bigger brains
  • p.21 70k-30k y ago: boats, oil lamps, bows, arrows, needles, art, religion, commerce, social stratification. reached Australia 45k y ago
  • p.22 language as a way to gossip. re: social information
  • p.23 gossiping is essential for cooperation in large numbers
  • p.24 sapiens language also helps to convey more information about the outside world. and it also allows talking about things that do not exist
  • p.27 large number of strangers can cooperate successfully by believing in a common myth
  • p.28 “There are no gods in the universe, no nations, no money, no human rights, no laws, and no justice outside the common imagination of human beings.”
  • p.38 the real difference between sapiens and chimpanzees becomes apparent at scales >150 (thousands)
  • p.51 average life expectancy was shorter but mostly due to high child mortality. adult life expectancy was good enough and many lived to 60s and 80s


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