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  • In 1973, a fossil hunter discovered the partial skeleton of a female Homo erectus in the Koobi

  • Fora formation of northern Kenya.

  • The specimen dated to 1.6 million years ago; today she’s known as KNM-ER 1808.

  • Her skeleton was pretty complete, given its age, including parts of her skull, limbs,

  • and pelvis.

  • And the anthropologists who studied her remains quickly noticed that there was something strange

  • about the bones of her legs and arms.

  • The texture of her bones was coarse, with patchy areas of new bone growth.

  • That coarse layer was evidence that something had seriously disrupted the normal functioning

  • of her bone cells before she died.

  • This wouldve been very painful, and ultimately, fatal.

  • But what could have caused this condition?

  • Oddly enough, it looks like it mightve been something she ate.

  • The researchers who originally studied the bones considered several possibilities, and

  • no diagnosis was a perfect fit.

  • But, they eventually settled on one that’s pretty uncommon these days: an overdose of

  • vitamin A.

  • While Vitamin A is usually good for us, helping us with color vision and healthy immune systems,

  • in high doses it can cause toxicity and a painful death.

  • Were talking peeling skin, gastrointestinal problems, and an increased risk of seizures,

  • along with bone pain and swelling.

  • And those original researchers thought that the most likely way that this poor Homo erectus

  • got ahold of that much vitamin A was by eating the livers of carnivores.

  • Now, like us, our hominin ancestors could - and did - eat pretty much everything.

  • But the downside of this is that it comes with serious risks - as that Homo erectus

  • found out.

  • We can track our history of eating just about anything back through the fossil record and

  • see the impact it’s had on our evolution.

  • And when we do, we see that our adventurous eating habits allowed us to expand our diets,

  • and enabled us to live almost everywhere.

  • So the fact is, there’s never been just one paleo diet.

  • But throughout time, part of the secret to our success as a species has been our early

  • - and sometimes fatal - experimentation with food.

  • A taste for meat was probably disastrous for that Homo erectus in Kenya, but it’s been

  • a big deal for our genus as a whole.

  • Our early hominin relatives, like Australopithecus anamensis and Paranthropus boisei, probably

  • had plant-based diets.

  • Likewise, our closest living relatives, chimpanzees and gorillas, eat lots of what we consider

  • low qualityfoods - things that aren’t calorie-dense, like grasses, leaves and unripe

  • fruit.

  • And they only get small amounts of animal protein from insects and the occasional bit

  • of meat.

  • But we think meat and otherhigh qualityfoods, like fat and bone marrow, probably

  • became a bigger part of the diet early in the history of our genus, Homo.

  • But there’s still some debate about who started eating meat first.

  • The earliest widely-accepted evidence of meat-eating comes from cut-marked bones found at the site

  • of Gona, Ethiopia from about 2.5 million years ago.

  • The hominins there - probably members of some early Homo species - were capable of breaking

  • down animal carcasses.

  • But we don’t know how much meat they ate, or if they were hunting their own prey or

  • just scavenging.

  • So, sites like Gona show us that hominins could get meat, but it’s hard to tell how

  • often they ate it.

  • Another site, called Kanjera South in Kenya is the first to show early members of our

  • genus -- most likely Homo habilis or Homo erectus - eating meat on a regular basis

  • The site dates back 2 million years, and it includes bones that have been cut into or

  • broken open with stone tools spanning hundreds of thousands of years.

  • So our ancestors were clearly eating meat and marrow pretty often by then.

  • But getting that meat came with serious risks.

  • Aside from the inherent threat of getting injured during a hunt, there are other dangers

  • - like wasting precious energy.

  • Even today, studies of many modern hunter-gatherer groups show that hunts often fail - even when

  • theyre using things like projectile weapons.

  • And even if those ancient hominins weren’t hunting the prey, scavenging it from other

  • predators posed its own problems.

  • They’d have to get to the carcass quickly enough to steal some meat before it went bad,

  • or, if they were feeling less patient, they’d have to try to drive the predator off of its

  • kill.

  • And neither option was particularly safe.

  • Okay, so what about fish?

  • Less risky than trying to scare a lion off a wildebeest carcass, right?

  • Well in 2010, a site from that same Koobi Fora formation in Kenya showed that, about

  • 1.95 million years ago, the hominins there were fans of seafood.

  • Among the animal remains found at the site were fossils of catfish and turtles - nice,

  • safe prey.

  • But there were also fossils of crocodiles found there.

  • So getting attacked by a croc while foraging for fish or turtles wouldve been a very

  • real hazard.

  • So, in terms of the calories and nutrients

  • it provided, meat was worth it.

  • But it was definitely risky to get.

  • Which is why our ancestors kept eating plants, too.

  • And while they seem less dangerous to find and eat, plants have their own fun, unexpected

  • ways of trying to kill us, or at least make us really sick.

  • Many plants, including things like unripe tomatoes, contain toxins that act as chemical

  • defenses against being eaten.

  • But you’d only feel the negative effects if you ate a LOT of it at once.

  • To avoid this, some animals feed on a lot of different plants in a day.

  • And one of the hallmarks of our genus, as weve evolved, is eating a more varied diet.

  • For example, one study of carbon isotopes in the fossils of several early Homo species

  • showed that they sometimes foraged from bigger plants like leafy bushes and trees, but also

  • ate ground plants like grasses and sedges.

  • Being willing to eat different plants made us more versatile and helped us avoid getting

  • poisoned by eating too much of the same thing.

  • And by continuing to eat our veggies, we gave ourselves some backup options, in case we

  • failed at hunting or scavenging.

  • So, many of the plant-based foods we might snack on today -- like cashews or kidney beans

  • -- came with serious risks in the past if they were consumed raw.

  • But we managed to survive as a species - somehow.

  • And there’s one more thing that millions of people all over the world eat today, which

  • our ancestors probably enjoyed, even though it mightve been painful to acquire.

  • I’m talking about insects and the products that some of them make, like honey.

  • Bugs are often overlooked as a potential meal in the fossil record because they don’t

  • leave behind a lot of obvious evidence.

  • Also, since most anthropologists have historically come from cultures that don’t eat insects,

  • they weren’t thinking of them as food.

  • And honey is pretty invisible in the fossil record, too, though we do have evidence of

  • fossil beesnests from one hominin site in South Africa.

  • But we know that our great ape relatives today eat both insects and honey.

  • And eating bugs has its advantages: theyre pretty easy and safe to get, and theyre

  • unlikely to give us pathogens the way scavenged meat could.

  • Theyre also a good source of protein, fat, and micronutrients.

  • And honey is incredibly energy-dense.

  • But how can we tell if our hominin relatives ate insects?

  • Researchers have analyzed bone tools from the site known as Swartkrans

  • in South Africa, which dates back 1.8 million years.

  • And the patterns of wear on those tools suggest that they may have been used for digging into

  • termite mounds.

  • And we know that termites were there because animals that eat termites have been found

  • there.

  • And there’s also evidence of termite damage on animal fossils from the site; yeah apparently,

  • some termites seem to eat bone, maybe for the nitrogen.

  • But there’s a debate about who made those bone tools, because weve found fossils

  • of both Homo and Paranthropus robustus there.

  • Now, while bugs are pretty easy to catch, some of them have pretty nasty defenses, like

  • venom, or vicious stingers or powerful bites - so there was risk for our hominin ancestors,

  • too.

  • Like, honey comes with the obvious downside of having to deal with bees.

  • Not to mention potentially falling out of the tall trees where some African bees make

  • their hives, which is a real risk for modern hunter-gatherers who collect honey today.

  • So, both now and in the past, human diets have varied all over the world, based on what’s

  • available and what different cultures have been like.

  • But weve always been very willing to take risks for anything that might be tasty.

  • Even in recent history!

  • For example, a study published in 2020 reported on a series of sites in Norway that dated

  • from between 6300 and 3800 years ago.

  • It found that the bones of cod fish there contained huge amounts of naturally occurring

  • toxic metals -- more than 20 times the amount of cadmium and up to four times as much lead

  • as is considered safe today.

  • The fish was toxic, but people ate it anyway.

  • So, our willingness to eat almost anything is a hallmark of the human story, going back

  • to our earliest hominin relatives.

  • Weve ingested nearly everything we could find, insects, mammals, reptiles, fish, birds,

  • plants, and animal byproducts like honey.

  • And so did hominins like Homo erectus.

  • But it didn’t always work out for us, as KNM-ER 1808 mightve found out the hard

  • way

  • So, anthropologically speaking, there’s no such thing as a single so-called paleodiet.

  • Weve made the best with whatever’s been available.

  • But we also know that, on the individual level at least, being an adventurous eater could

  • be risky business.

  • OK if this episode got you hungry for more human evolution content, be sure to check

  • out our Human Evolution Learning Playlist.

  • Youll learn the fundamentals about what we know, and what were still discovering,

  • about the evolution of Homo sapiens.

  • And a big thank you to this month’s Eontologists:

  • Patrick Seifert, Jake Hart, Jon Davison Ng, Sean Dennis, and Steve!

  • And as always I wanna thank you for joining me in the Konstantin Haase Studio.

  • Be sure to subscribe at youtube.com/eons for more adventures in evolution.

In 1973, a fossil hunter discovered the partial skeleton of a female Homo erectus in the Koobi

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我们祖先的危险古饮食(The Risky Paleo Diets of Our Ancestors)

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    joey joey 發佈於 2021 年 05 月 03 日
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