HIST103 Lecture Notes - Lecture 4: Fisherian Runaway, Sebaceous Gland, Handicap Principle
22 Feb 2017
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Document Summary
. 5 million or 500,000 years ago flexible and adaptive to thought: problems brain is abnormally large in relationship to other mammals. Theories of encephalization: expensive tissue hypothesis, fitness indicator (cid:498)cognitive fluidity(cid:499: theories of encephalization why do we have larger brains, cognitive fluidity something about the way our brain is wired that makes it. Neocortical mass new brain, observed more brain mass than expected. Positive feedback loop behavioral changes led to dietary changes led to behavioral changes which tissues which . Allowed selection pressures to select for neocortical mass what were those. Birth had to be sooner throughout time so that the size of the baby"s head. More complex foraging behavior higher quality diet & larger brain. Higher diet quality increased energy availability larger brain. Higher diet quality (reduced bulk/ more rapid assimilation) smaller gut pressures? (increased energy availability) larger brain. Freed a degree of flexibility in the ontogenetic appropriation of expensive.
