Saturday 14 June 2014

Humans are brainy weaklings

The heading is obvious to most of us: the achievements of the human mind eclipse anything achieved by other animals. By contrast, in the physical sphere, there are animals that can run or swim faster & lift greater weights.

Some of the difference in physical capability are due to reasons other than strength: e.g. swimming speed of some fish is substantially due to their torpedo shape. Four legs & a flexible spine give the big cats a longer stride which partly explains their great speed.

While there is an obvious relationship between size & strength, gram-for-gram, chimpanzee muscle is twice as strong as human muscle.

Recent research, described in the linked article, indicates that the parts of the human brain associated with intellect has been the site of accelerated evolution. No surprises there. Puzzlingly, in parallel, human muscle has evolve to be less strong, gram-for-gram. Result is the greater intelligence & lesser strength of humans, compared with our closest living relative, the chimpanzee.

http://www.economist.com/news/science-and-technology/21602988-human-beings-are-brainy-weaklings-muscled-out / geek nerd swots weedy jocks stupid cliche cliché paper just published PLOS Biology research researchers Chinese Academy of Sciences Max Planck Institute Germany evolutionary evolution truth Katarzyna Bozek colleagues how quickly human tissues have evolved compared other mammals human brain stronger species muscles weaker demonstration science hypothesis human brains 2% adult body weight fifth metabolic energy Richard Wrangham Harvard University cooking makes more nutrients available food raw state neurological expansion Homo sapiens supply brain energy other human organs under pressure economise muscle economised a lot Dr Bozek colleagues study metabolome water-soluble chemicals small molecules sugars amino acids vitamins biochemistry research researchers five types of tissue individuals four species mammal humans chimpanzees rhesus monkeys mice previously healthy dead individuals humans died mainly in accidents tissue types brain prefrontal cortex visual cortex cerebellum thigh muscle kidney metabolic enhancement metabolomes two species proportional time evolving separately larger differences particular type of tissue suggest strong specific evolutionary pressures on that tissue human prefrontal cortex complex cognitive behaviours abstract thought show markedly greater differences metabolome equivalent other species tissues thigh-muscle metabolism Homo sapiens sacrificed brawn for brains /

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