Monday, May 17

How early humans’ foraging for food fanned the flames of evolution | Evolution


Human evolution and world exploration were shaped by a hunger for tasty food, “a quest for delight,” according to two leading scholars.

Ancient humans who had the ability to smell and crave more complex aromas, and to enjoy bitter tasting foods and drinks, gained evolutionary advantages over their less picky rivals, the authors of a new book argue about the role taste plays in our development. .

Some of the most important inventions early humans made, such as stone tools and the controlled use of fire, were also driven in part by their quest for taste and a preference for food they found delicious, according to the new hypothesis. .

“This key moment in which we decide whether or not to use fire has, in essence, only the taste of food and the pleasure it provides. That’s the time when our ancestors are faced with the choice between cooking things and not cooking things, ”said Rob Dunn, professor of applied ecology at North Carolina State University. “And they chose the flavor.”

Cooked food tasted more delicious than raw food, and that’s why we chose to keep cooking it, he says: not just because, as the academics have argued, cooked meat and roots were easier and safer to digest, and they rewarded us. with more calories.

Some scientists think that the controlled use of fire, which was probably adopted a million years ago, was fundamental to human evolution and helped us develop bigger brains.

“Having a big brain becomes less expensive when you release more calories from your food by cooking it,” said Dunn, who co-wrote Delicious: The Evolution of Flavor and How It Made Us Human with Monica Sanchez, medical anthropologist.

However, accessing more calories was not the main reason why our ancestors decided to cook food. “Scientists often focus on what the bottom line is, rather than the immediate mechanism that allowed our ancestors to make the decision. We made the choice for its delight. And then the bottom line was more calories and fewer pathogens. “

Human ancestors who preferred the taste of cooked meat to raw meat began to enjoy an evolutionary advantage over others. “In general, taste rewards us for eating the things we needed to eat in the past,” Dunn said.

In particular, people who developed a preference for complex flavorings likely developed an evolutionary advantage, because the smell of cooked meat, for example, is much more complex than that of raw meat. “Meat goes from having dozens of flavors to having hundreds of different flavor compounds,” Dunn said.

Prehistoric Woolly Mammoth Hunters
Prehistoric woolly mammoth hunters. Photograph: North Wind Picture Archives / Alamy

This predilection for more complex scents made early humans more likely to turn their noses toward old, rotten meat, which often has “really simple smells.” “They would have been less likely to eat that food,” Dunn said. “The retronasal smell is a very important part of our flavor system.”

The legacy of humanity’s remarkable preference for foods that have a multitude of aromatic compounds is reflected in today’s “high-food culture,” Dunn says. “It’s a food culture that really satisfies our ability to appreciate these aroma complexities. We have prepared this very expensive type of cuisine that somehow fits in with our old sensory capacity. “

Similarly, our propensity for sour-tasting foods and fermented beverages like beer and wine may be due to the evolutionary advantage that consuming acidic foods and beverages gave our ancestors.

“Most mammals have bitter taste receptors,” Dunn said. “But in almost all of them, with very few exceptions, the sour taste is aversive, so most primates and other mammals, in general, will spit it out if they taste something sour. They do not like it “.

Humans are among the few species that like acid, he says, another notable exception being pigs.

At some point, he thinks, the bitter taste receptors in humans and pigs evolved to reward them if they found and ate decaying food that tasted sour, especially if it also tasted a bit sweet, because that’s how bacteria taste. acidic. And that, in turn, is a sign that the food is fermenting, not rotting.

“The acid produced by the bacteria kills the pathogens in rotten food. So we thought that the bitter taste on our tongue, and the way we appreciate it, may actually have served our ancestors as a kind of pH strip to know which of these fermented foods was safe, ”Dunn said.

Human ancestors who were able to accurately identify decaying foods that were actually fermenting, and therefore fine to eat, would have had an evolutionary advantage over others, he argues. If they also figured out how to safely ferment food to eat during the winter, they further increased their food supply.

The negative consequence of this is that the alcoholic, fermented fruit juice, a kind of “proto wine,” would have tasted good too, and that probably led to horrible hangovers.

“At some point, our ancestors developed a version of the gene that produces the enzyme that breaks down alcohol in our bodies, which is 40 times faster than that of other primates,” Dunn added. “And that really made our ancestors that much better able to get the calories from these fermented beverages, and it would probably also have decreased the extent to which they had hangovers every day from drinking.”

The taste also prompted humanity to innovate and explore, Dunn says. He believes that one of the reasons our ancestors were inspired to start using tools was to get food that would otherwise be inaccessible and that tasted delicious: “If you look at what chimpanzees use tools for, almost they are always really delicious things, like honey. “

Having a portfolio of tools that they could use to find tasty things to eat gave our ancestors the confidence to explore new environments, knowing that they could find food, no matter what season threw them. “It really allows our ancestors to move into the world and do new things.”

Still Life with Turkey Pie, by Pieter Claesz, 1627.
Still Life with Turkey Pie, by Pieter Claesz, 1627. Photography: FineArt / Alamy

Stone tools, in particular, “speed up” humans’ ability to find delicious food. “Once they can hunt, using spears, they have access to this whole world of food that was previously unavailable.”

At this point, Dunn thinks that humanity’s search for tasty food began to have dire consequences for other species. “We know that humans around the world hunted species to extinction, once they figured out how to hunt really effectively.”

Dunn strongly suspects that the mammals that went extinct for the first time were the most delightful. “From what we were able to reconstruct, it appears that mammoths, mastodons, and giant sloths would have been unusually tasty.”

To replicate the eating habits of prehistoric humans, the book, published later this month, details how a scientist dropped a horse that had just died into a pond and assessed how it fermented over time. “I would taste some meat to see if it was safe to eat. He described it as delicious, a bit like blue cheese, ”Dunn said.


www.theguardian.com

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