Science fiction often condemns humanity to evolve into skinny creatures with an exorbitantly bloated head., whose whole life depends on the achievements of scientific and technological progress. Fortunately, reality is much more interesting and far from predictable, according to science fiction writers.
Фото: Andriyko Podilnyk / Unsplash
An excursion into history
We all know what Neanderthals looked like: massive brow ridges, an elongated skull, a wide nose, massive bones and, most likely, red hair and freckled skin. But if you look at the hunter-gatherers, whose tribes inhabited Europe in 7000-8000. BC. and whose DNA analysis is currently being done by genetics around the world, the picture will radically change. They were dark-skinned, blue-eyed people, reminiscent of some of the inhabitants of modern Afghanistan. Subsequently, the combination “dark skin, light eyes” disappeared from the gene pool of ancient Europeans, being replaced by the opposite one. Through the migration of farming families from the Middle East, dominated by dark eyes and fair skin, the peoples mingled and eventually gave birth to the Europeans we know today.
Middle Eastern farmers had another interesting ability: they were carriers of genes for lactose tolerance, which allowed them to consume milk. In ancient hunter-gatherers, it was either completely absent, or was very weakly expressed. In addition, farmers consumed an order of magnitude less meat and much more starch, and therefore the provision of the body with vitamin D in their family depended both on the consumption of milk and on a sufficient amount of sunlight – hence the lighter skin. The dark-skinned population of Europe was eventually exterminated by the invaders, and only a small part of it was assimilated with the farming clans.
Here’s a good example of relatively fast human evolution. Little things like the transition from hunting and gathering to cultivating the soil are enough for the genetic code to undergo noticeable changes. Dark skin, probably inherited from African ancestors, turned from an advantage to a disadvantage if most of the calories in the diet came from cultivated grains, and not from wild meat rich in vitamin D.
The appearance of the Europeans was also influenced by the influx of genes from the inhabitants of East Asia, who at that time resembled the modern Chukchi and other peoples of the Siberian group. Thus, ancient Europe became a real “cauldron, in which all possible races boiled and interacted, forming new combinations of genes before our very eyes.” Reminds modern megacities, doesn’t it?
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Dance of evolution
We used to think of evolution, described by Charles Darwin in 1859, as a kind of slow “dance”: nature chooses the organisms most adapted to the conditions of a given environment for reproduction and, thus, increasing the chances of survival. This process, known as natural selection or differential reproduction, means that specific organisms will pass on more of their genes to the next generation than less fit members of the same species group.
In turn, the genetic changes themselves, which modern scientists read from the “chronicle” of fossils, take much longer. A good example is the history of forest mammals, predators of the genus Hyracotherium, which in the process of evolution have lost their lateral fingers due to an increase in the central one. For 55 million years, the animal has changed beyond recognition, turning into a large horse that is well known to us, feeding on vegetation.
However, evolution is often very fast. Biologists Peter and Rosemary Grant of Princeton University in New Jersey have shown how Galapagos finches can vary in beak size depending on climatic conditions and the type of food available. This is the so-called microevolution: both of these traits are preserved in the genotype of birds, and as soon as conditions change, one of them begins to dominate the other.
Evolutionary biologists David Lahti of Queens College at City University of New York and Paul W. Ewald of the University of Louisville argue that there is nothing exceptional about the phenomenon of rapid evolution. Rapid change is simply the result of a response to intense changes in nature, through which the body learns to resist external factors. However, not everything is so simple: in order to ensure rapid evolution, the genome must initially contain a sufficient number of variations of a particular trait.
Lahti adds that for people, social selection is gradually becoming paramount. In particular, the presence of hostile groups, coupled with the need for close intragroup cooperation, led to the fact that a person’s social life became more complicated by several orders of magnitude, and his brain became large and complex. Scientists do not know in what form the relationship between the ancient black Europeans and settlers from the East developed: probably, as in any society, they fought, exchanged, and even interbred with each other. All that we can judge about is the suppression of some signs and the formation of others, the prints of which have been preserved in the anatomy and genes of fossil remains.
Conclusion
Genes for both dark and light skin have not disappeared anywhere. Nature is rarely wasteful: the pale skin of northerners helps them partially tolerate vitamin D deficiencies, while the dark skin of southerners is also an adaptation to hot, sunny climates. Since climatic shifts occur annually, even now it is impossible to say with certainty how the appearance of Europeans will change in just 500 years.
Human evolution has never stopped – this is the whole essence of natural selection. It cannot be said that, as a whole, as a species, we are developing in a certain direction: people of the future will not become all creatures with large heads and skinny bodies, despite the fact that cheap science fiction is so fond of this image. From generation to generation we adapt to external factors such as disease, climate change and even the transformation of social structures. Probably, in the future, a person will master science and technology so that he will be able to completely control his development and modify the body at his own will. But this is a completely different conversation.
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