Human evolution: as apex predators (Introduction)

by David Turell , Monday, October 17, 2022, 17:18 (766 days ago) @ David Turell

Latest theory:

https://www.sciencealert.com/ancient-humans-were-apex-predators-for-2-million-years-stu...

"Paleolithic cuisine was anything but lean and green, according to a study on the diets of our Pleistocene ancestors.

"For a good 2 million years, Homo sapiens and their ancestors ditched the salad and dined heavily on meat, putting them at the top of the food chain.

It's not quite the balanced diet of berries, grains, and steak we might picture when we think of 'paleo' food.

"But according to a study last year by anthropologists from Israel's Tel Aviv University and the University of Minho in Portugal, modern hunter-gatherers have given us the wrong impression of what we once ate.

"'This comparison is futile, however, because 2 million years ago hunter-gatherer societies could hunt and consume elephants and other large animals – while today's hunter gatherers do not have access to such bounty," researcher Miki Ben‐Dor from Israel's Tel Aviv University explained in 2021.

"A look through hundreds of previous studies – on everything from modern human anatomy and physiology to measures of the isotopes inside ancient human bones and teeth – suggests we were primarily apex predators until roughly 12,000 years ago.

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"We can find ample evidence of game hunting in the fossil record, but to determine what we gathered, anthropologists have traditionally turned to modern-day ethnography based on the assumption that little has changed.

"According to Ben-Dor and his colleagues, this is a huge mistake.

"'The entire ecosystem has changed, and conditions cannot be compared," said Ben‐Dor.

"The Pleistocene epoch was a defining time in Earth's history for us humans. By the end of it, we were marching our way into the far corners of the globe, outliving every other hominid on our branch of the family tree.

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"'We decided to use other methods to reconstruct the diet of stone-age humans: to examine the memory preserved in our own bodies, our metabolism, genetics and physical build," said Ben‐Dor.

"'Human behavior changes rapidly, but evolution is slow. The body remembers."

For example, compared with other primates, our bodies need more energy per unit of body mass. Especially when it comes to our energy-hungry brains. Our social time, such as when it comes to raising children, also limits the amount of time we can spend looking for food.

"We have higher fat reserves, and can make use of them by rapidly turning fats into ketones when the need arises. Unlike other omnivores, where fat cells are few but large, ours are small and numerous, echoing those of a predator.

"Our digestive systems are also suspiciously like that of animals higher up the food chain. Having unusually strong stomach acid is just the thing we might need for breaking down proteins and killing harmful bacteria you'd expect to find on a week-old mammoth chop.

Even our genomes point to a heavier reliance on a meat-rich diet than a sugar-rich one.

"'For example, geneticists have concluded that areas of the human genome were closed off to enable a fat-rich diet, while in chimpanzees, areas of the genome were opened to enable a sugar-rich diet," said Ben‐Dor.

"The team's argument is extensive, touching upon evidence in tool use, signs of trace elements and nitrogen isotopes in Paleolithic remains, and dental wear.

"It all tells a story where our genus' trophic level – Homo's position in the food web – became highly carnivorous for us and our cousins, Homo erectus, roughly 2.5 million years ago, and remained that way until the upper Paleolithic around 11,700 years ago."

Comment: not the usual view, but it recognizes that we have a new food supply in farming which is only 11,000 years old.