Human energy use (internal)

This is not about burning fossil fuels or renerables. More about calories than kilowatts (although the two are inter convertible): A link:

Humans Paid for Bigger Brains With Gas-Guzzling Bodies - The Atlantic

Seems well written. It links back to two Pontzer et al. articles, which you are excused for not reading unless the word 'paywall' is invoked.

For clarity replace this sentence
"We are a more calorific diet of tubers and meat."
with
"We ate a more calorific diet of tubers and meat."
Ed Yong gets forgiven for 'one letter over on the keyboard' but Atlantic editors did not get past my beady eyes

If you need it even shorter. Human brain is an unusually large energy consumer. We managed it not by cutting back other systems, but by eating more. I suppose this is correct, bu but frankly they they had me with 'double-labeled stable isotope analysis'

Also added more body fat, 'cause the brain never sleeps (seriously it does not) and that fire needs to be kept going even if the next meal is some ways off.

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How much intake upgrading depended on making fires is a separate, related issue. I happen to think, a lot. Certainly once you have large local population densities linked to agriculture, it's time to learn to cook.

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Bigger brains there are; elephants and most whales at least. I am not sure that their energy usage has been deeply studied.

 

I agree that aspect is weak, linked with current human %fat, which may mean little or nothing in relation to paleo humans.

For current humans excepting about 2 billions on the bottom rungs of the ladder, low %fat correlates with longevity.. At the other extreme, high %fat correlates with late-life killers. Paleo bones suggest that paleo humans did not generally live to an age when those killers kick in (also they would have been post reproductive). We are at a loss to identify evolutionary pressure against fatties.

Perhaps the authors would have done better by emphasizing that there were no others 'paleos' who moved as far as hominids in search of food. Fat does not fossilize, so I think relevant numbers might never be known.

Zoos of the world (I call them prisons for the innocent) have large research-able primate populations. There are 'ethics committees' standing in the way of feeding primates high-fat, high-sugar diets, just to see how the inmates bulk up. I think we could set this issue aside and consider authors' other, brain-oriented ideas.

 

These quotes @4 are giving me some trouble

"Decent through modification does not select for the most efficient creatures. The alpha species is always less efficient than other species, why would it be more efficient. Traits are selected for by if they are more likely to produce viable offspring, not if they are efficient."

"evolution selects for efficiency in times of distress"

First is an unsupported declaration and one (maybe two) false paradoxes. The second contradicts the first.

Energy efficiency can mean many things, ideally a writer intends a specific meaning, and reveals it.

I have looked around for a general-level treatment of resources in the context of evolutionary fitness landscapes, but as yet have no satisfactory link.

In jr. high school one very obese fellow could outrun me. Perhaps some psychological scars never heal and could my vision on this topic.

 

With mechanical transportation devices it seems simple to define energy efficiency. So many ton-kilometers per so much fuel energy. Of course it could be more complicated by including travel time or surface elevation changes. That sort of thing used to be done a lot in PriusChat and related websites.

Move into biology and it is more complicated because there are more terms that a writer may wish to include. Or optimize. Nothing at all wrong with that, if done explicitly. But a declaration that energy efficiency has nothing to do with reproductive success does not seem a good beginning.

There is a substantial literature on how energy efficiency (explicitly defined) has been optimized by evolution. However I have not found a general review paper that I'd try to 'sell' here.

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Of biological systems (apparently) optimized by evolution my favorite example is countercurrent circulation. It occurs very widely, and apparently because the 'toolkit' of precursor structures is so often available. Years ago when I learned that the NHW20 traction battery electrodes were redesigned as countercurrent circulation, it was a giddy moment to say the least.

The 100 to 200 watts continuously produced as heat by the human brain requires a 'radiator' which is your sinuses. Another countercurrent circulation. Yet it could be seen as a kludge because so susceptible to bacterial and viral infection.

 

There may be no difference in our positions, other than definitions of energy efficiency. Hard to tell.

There is probably something on the subject by one of the Odum brothers - I shall have to look. Those were a couple of stars (in the terrestrial sense).

In modern times, a famous example is Dutch who had several years of small kids during food-shortage years in the 1940's. Now are the country with the tallest (average) people. I think this has been worked out very well in terms of caloric intake. A next step might be to measure fecundity of a given cohort, over a range of sizes. They have all the data needed for sure. They are Europeans with a penchant for measuring things

This began as a thread on humans. Fine to extend it more broadly, but arguing from this primate to animals or organisms more broadly may not be the best choice. We are an oddity here.

James Brown (ecologist not musician) went in the other direction and supplies metabolic rules for all biological organisms.