BISC 102 Final: Study Notes - Lectures 18, 19
19 Jan 2018
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Humans + chimps last shared common ancestor ~5-7 mya. Hominin: species more closely related to humans than chimps. Humans = bipedal, gorilla + chimp = knuckle-walkers, gibbons + orangutans = arboreal: australopithecus afarensis. Less chimp-like than expected: homo ergaster ( working man) More pair-bonding than in ancestors: humans: brains. --> led to increased brain size, decreased jaw and jaw muscles. Costs: large brains = more energy, increased juvenile dependence. Benefits: large brains = increased social complexity: human genome project. Differences: chromosomal arrangement genes (nucleotide sequence, location, duplications) (related to brain development) Human head and chimp lice lineages diverged at same time hominins and ancestral chimps diverged. Compare dna of human head lice + dna of chimp lice to est. when they last shared common ancestor. Dna suggests most recent common ancestor ~ 6 million years ago. Hominins + head lice co-speciated from ancestral chimps + lice: new niche hypothesis:
