Survival of the Fattest:
fat babies were the key to evolution of the large human brain
SC Cunnane & MA Crawford 2003
Comparative Biochemistry & Physiology Part A 136
doi 10.1016/S1095-6433(03)00048-5
In the past 2 Ma, the hominid lineage leading to Hs evolved significantly larger & more sophisticated brains than other primates.
We propose:
the Hs brain was a product of having first evolved fat babies:
the fattest infants became, mentally, the fittest adults.
Hs babies have brains & body fat, each contributing to 11–14 % of body Wt, this situation is unique amongst terrestrial animals.
Body fat in human babies provides 3 forms of insurance for brain development, not available to other land-based spp:
- a large fuel store in the form of fatty acids FAs in triglycerides,
- the FA precursors to ketone bodies: key substrates for brain lipid synthesis,
- a store of long chain poly-unsaturated fatty acids LC-PUFAs, particularly docosahexaenoic acid DHA, needed for normal brain development.
The triple combination of high fuel demands, inability to import cholesterol or saturated FAs & dependence on DHA puts the mammalian brain in a uniquely difficult situation vs other organs,
this makes its expansion in early humans all the more remarkable.
Fresh- & salt-water shore-lines provided
- a uniquely rich, abundant & accessible food supply,
- the only viable environment for evolving both body fat & larger brains in human infants.
Arboreal apes need lightweight bodies, hylobatids
have SC fat,
terrestrial hominins living in forests (with fat forest
pigs) sleeping in shelters and armed with weaponry
did not burn off their SC fat layer which was
advantageous for sleeping on damp forest floor.
On Tuesday 1 February 2022 at 17:26:33 UTC, DD'eDeN aka note/nickname/alas_my_loves wrote:
Arboreal apes need lightweight bodies, hylobatidsGibbons need, and can afford, some
have SC fat,
extra body weight -- for effective
brachiation.
insulation at night, not being social.
terrestrial hominins living in forests (with fat forest
pigs) sleeping in shelters and armed with weaponry
did not burn off their SC fat layer which was
advantageous for sleeping on damp forest floor.
That must be when hominins acquired
such good night sight, such sensitive
hearing, and such a powerful sense of
smell. And where their infants and
other young learned to be so silent,
both by day and by night.
It all begins to fit.
On Tuesday, February 1, 2022 at 11:15:21 AM UTC-5, littor...@gmail.com wrote:forest floor.
Survival of the Fattest:
fat babies were the key to evolution of the large human brain
SC Cunnane & MA Crawford 2003
Comparative Biochemistry & Physiology Part A 136
doi 10.1016/S1095-6433(03)00048-5
In the past 2 Ma, the hominid lineage leading to Hs evolved significantly larger & more sophisticated brains than other primates.
We propose:
the Hs brain was a product of having first evolved fat babies:
the fattest infants became, mentally, the fittest adults.
Hs babies have brains & body fat, each contributing to 11–14 % of body Wt, >> this situation is unique amongst terrestrial animals.
Body fat in human babies provides 3 forms of insurance for brain development, not available to other land-based spp:
- a large fuel store in the form of fatty acids FAs in triglycerides,
- the FA precursors to ketone bodies: key substrates for brain lipid synthesis,
- a store of long chain poly-unsaturated fatty acids LC-PUFAs, particularly docosahexaenoic acid DHA, needed for normal brain development.
The triple combination of high fuel demands, inability to import cholesterol or saturated FAs & dependence on DHA puts the mammalian brain in a uniquely difficult situation vs other organs,
this makes its expansion in early humans all the more remarkable.
Fresh- & salt-water shore-lines provided
- a uniquely rich, abundant & accessible food supply,
- the only viable environment for evolving both body fat & larger brains in human infants.
Arboreal apes need lightweight bodies, hylobatids have SC fat, terrestrial hominins living in forests (with fat forest pigs) sleeping in shelters and armed with weaponry did not burn off their SC fat layer which was advantageous for sleeping on damp
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