Human evolution is the most complex issue that scientists have been wrestling with for many decades, and many subtleties are associated with it. Not everyone knows, for example, that Neanderthals were not the ancestors of Cro-Magnons, but only a kindred species of people. But what exactly helped Homo sapiens to go the way that led him to a modern man? There are several theories on this score …
Drug theory
Terence Kemp McKenna, a philosopher and connoisseur of psychedelics, once suggested that people gained consciousness by feeding on special psychogenic mushrooms, and of alien origin. Mushrooms grew only in the interval from 18 to 12 thousand years ago, but during this time they managed to change the mind of the former monkeys, turning them into people. This theory is not popular, but we must give it its due - some mushrooms really could survive on other planets, and also affect the human brain with constant intake.
Aquatic theory
Unlike the vast majority of other hominids, humans have very little hair. Scientists are still not sure why, but one theory to explain this was put forward in 1929 by biologist Alistair Hardy. Perhaps about 6-8 million years ago, our distant ancestors got food by swimming and diving, and gradually got rid of excess fur, acquiring in return subcutaneous fat, like whales or dolphins.
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The "brainy Eve" theory
We all got our mitochondrial DNA from a woman who lived in Africa about 200,000 years ago, who is called "mitochondrial Eve." British neuroscientist Colin Blakemore went further by stating that we also owe the size of our brains to this woman. Due to a genetic mutation, her brain could be 30% larger than that of her contemporaries, which she passed on to all descendants. They survived where the children of other ancient mothers died, only due to the size of the brain.
Violence theory
Cravings for violence are by no means the best of our traits, but perhaps it is thanks to it that we evolved. This theory was put forward in 1953 by the Australian anthropologist Raymond Dart. Ancient people explored new lands, seeking to drive out other tribes, conquer them and even eat them. Maybe because of this, other species of humans died out, and the survivors interbred with Cro-Magnons - often not of their own free will.
Parasite theory
Another theory explains why we got rid of hair from all over the body, through the fight against parasites. According to this theory, the lack of body hair helps reduce the chance of catching a parasite like a tick or flea. Ancient people protected from parasites were less sick, but remained defenseless against the cold. It was then that the brain came in handy, guessing to create clothes and make a fire.
Food theory
How did the diet of Homo sapiens differ from the diet of other ancient hominids? Two items - meat and carbohydrates. When we started eating meat about 3 million years ago, more neurons gradually formed in our brains. People learned to cooperate on hunting, developing social skills. Carbohydrates are the main food for the brain, which most likely influenced its evolution.
Climate theory
People who have lived on Earth for tens of millennia have seen repeated climate changes - from heat to glaciers. Perhaps each abrupt change provoked us to no less dramatic leaps in development - to adapt to unstable weather conditions.
Crossing theory
When the Cro-Magnons left Africa 60 thousand years ago, they crossed paths with Neanderthals and Denisovans, other hominid species. The result has led to interspecies crossing and the emergence of hybrids - in our DNA there are still traces of them. In ancient times, it was hybridization that helped people adapt to new living conditions outside the African continent.
Bipedalism theory
The habit of our ancestors to move on their feet could affect the features of our brain. The logic is as follows - due to upright posture, the shape of the pelvis in women has changed, and the birth canal has narrowed. Because of this, the skulls of babies became softer - in order to more successfully overcome new obstacles. And then it was the soft skulls that allowed the brain to grow in size.
Throw theory
In 1991, the remains of a separate species of hominids were found on the territory of the Georgian city of Dmanisi. Their weapons were primitive, but there is a theory that they skillfully knew how to throw stones, driving away saber-toothed lions. Oddly enough, such skills could have a positive effect on the development of the human brain - after all, the area responsible for coordination of the hands and eyes when throwing is located in the same place as the area of speech. Not to mention, joint defense against predators contributed to socialization.