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Although today's humans are the result of thousands of years of evolution, do not think that we are the end product of the development of our species. Although it may not seem so, the truth is that our bodies and behaviors are still undergoing transformations and adapting to the environment in which we live.
In fact, several studies have pointed out that not only is there evidence that we are continuing to evolve, but this process is happening very fast, especially since the emergence of agriculture. With that in mind, Jessica Hullinger of the Mental_Floss portal has gathered some signs of our ongoing evolution, and you can check out the following:
1 - Our brain is shrinking
As you know, we humans have been developing larger brains throughout our evolutionary history, and this has given us an incredible advantage over other species that live on Earth. However, larger brains also require a huge amount of energy to function, and there is evidence that in the last 30,000 years they have begun to "shrink."
According to Jessica, the average volume of the human brain has shrunk from 1,500 cubic centimeters to about 1,335,000 cm3 - which would be equivalent to removing a tennis ball-sized chunk from its brains - and there are various theories as to why brains are shrinking.
For some researchers, they're getting smaller simply because we're getting more… dumb. According to proponents of this theory, throughout history, brains have shrunk in size as societies have become more complex and larger, suggesting that the security that modern societies offer nullifies the need to "use one's head" to survive.
There are also researchers who believe that smaller brains are evolutionarily advantageous, as they would make us less aggressive, allowing us to have a more peaceful coexistence. And yet there are scientists who don't think we're getting stupid, but that our brains are getting smaller to become more efficient, so that they would reorganize so that they could work faster.
2 - We are becoming tougher
According to Jessica, researchers have identified 1,800 genes that have only become prevalent in humans in the last 40,000 years, and many of them are associated with fighting infectious diseases. Thus, people living in cities have developed mutations that make them more resistant to tuberculosis and leprosy, for example, and there are dozens of new genetic variants against malaria spreading in Africa.
3 - We are becoming lactose tolerant
We here at Mega Curious have already talked about how humans began to develop lactose tolerance - and you can check it out through this link. But, basically, the gene that controlled our ancestors' ability to digest dairy foods became inactive as babies “weaned” from their mothers.
According to Jessica, when our ancestors began to tame animals like cows, sheep and goats, milk and dairy products became new sources of calories and nutrients. And individuals who brought the genetic mutation that allowed them to consume these foods without dying of a stomachache began to pass on the news to their offspring.
Interestingly, this genetic trait continues to be transmitted, as not all humans can consume lactose quietly. A 2006 study found that populations occupying eastern Africa 3,000 years ago were still developing tolerance, and the mutation that allows lactose digestion is present in 95% of the descendants of the peoples of northern Europe.
4 - Wisdom teeth are disappearing
Our ancestors began to have wisdom teeth because of their diet, based on foods such as roots, leaves, nuts, raw meat and even a small bone. It turns out that tearing and chewing these rustic items caused great tooth wear, so third molars probably arose to accommodate the eating habits of our ancestors.
However, over time, our diet became based on foods that are easier to grind, not to mention that today we have the help of utensils that allow us to cut, slice, mince, peel etc. our food. As a result, our jaws became smaller - and wisdom teeth, in addition to losing their usefulness, lost space in our mouths, which is why many people have problems when they are born.
Thus, according to Jessica, wisdom is now considered a “human vestigial structure” - as is the appendix, coccyx and body hair - and the current estimate is that 35% of the world's population is born without these teeth, and the trend is that they disappear completely.
5 - Blue eyes came up
Originally, all humans had only brown eyes until someone was born with a genetic mutation that gave rise to the color blue. This individual lived between 7 and 10,000 years ago somewhere in the Black Sea region, and he was responsible for spreading this trait to a portion of the population.
The discovery is remarkable, but no one can explain why the blue eyes persisted genetically among us. According to Jessica, one theory is that this trait was used by our ancestors as a kind of paternity test, since parents with blue eyes conceive children with blue eyes. Thus, it is possible that our blue-eyed ancestors sought mates with eyes of this color to ensure they were faithful.
Although this idea is highly speculative, a study by Norwegian researchers found that brown-eyed people do not seem to be more or less attracted to individuals with specific eye colors. On the other hand, blue-eyed men seem to express a preference for women who also have eyes of this color - supporting the evolutionary "paternity test" theory.