Science fiction often dooms humanity to evolve into lean creatures with an unreasonably inflated head, whose entire life depends on the achievements of scientific and technological progress. Fortunately, the reality is much more interesting and far from predictable, according to the science fiction writers.
Excursion to the history
We all know what the 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 hunter-gatherers, the tribes of which inhabited Europe in 7000-8000. BC. and DNA analysis of which is currently being done by geneticists around the world, the picture will radically change. They were dark-skinned, blue-eyed people resembling some of the inhabitants of modern Afghanistan. Later, the combination of “dark skin, bright eyes” disappeared from the gene pool of ancient Europeans, replaced by the opposite. Thanks to the migration of farming families from the Middle East, which were dominated by dark eyes and fair skin, the peoples mingled and ultimately spawned those Europeans who are known to us today.
The Middle Eastern farmers had another interesting ability: they were carriers of lactose tolerance genes that allowed them to eat milk. In ancient hunter-gatherers, he either was completely absent, or was very weakly expressed. In addition, farmers consumed an order of less meat and much more starch, and therefore providing the body with vitamin D in their family depended on both milk consumption and sufficient sunlight – hence the lighter skin. The dark-skinned same population of Europe was eventually exterminated by invaders, and only a small part of it was assimilated with farm clans.
Here is a good example of the relatively rapid evolution of man. It is enough such a trifle as the transition from hunting and gathering to cultivation of soil, so that the genetic code has undergone noticeable changes. Dark skin, probably inherited from African ancestors, was disadvantageous if most of the calories in the diet came from cultivated cereals, and not from the meat of wild animals rich in vitamin D. Blue eyes were retained as recessive (i.e., less priority ) sign and rarely showed themselves, and therefore an increasing number of children were born with brown eyes.
The appearance of Europeans was also influenced by the inflow of the genes of the inhabitants of East Asia, which at that time resembled the modern Chukchi and other Siberian groups. Thus, ancient Europe became the most real “boiler in which all possible races were brewed and interacted, forming new combinations of genes before our eyes. It reminds modern megacities, is not it?
Dance of Evolution
We are used to thinking about the evolution described by Charles Darwin in 1859 as a kind of slow “dance”: nature chooses the organisms most adapted to the conditions of the given medium for reproduction and, thus, increasing the chances of survival. This process, known as natural selection or differential reproduction, means that specific organisms will transmit most of their genes to the next generation, the less adapted members of the same species group.
In turn, the genetic changes themselves, which modern scientists read in the “chronicle” of fossils, take much longer. A good example is the history of forest mammalian predators of the genus Hyracotherium, which in the course of evolution lost side fingers due to the increase in the central one. For 55 million years the animal has changed beyond recognition, having turned into a large horse, well-known to us, feeding on vegetation.
However, evolution often occurs very quickly. Biologists Peter and Rosemary Grant of Princeton University in New Jersey in their works have demonstrated how in Galapagos finches the size of the beak can vary depending on climatic conditions and the type of food available. This is the so-called microevolution: in the genotype of birds, both of these traits are preserved, and as soon as the conditions change, one of them begins to dominate the second.
Evolutionary biologists David Lahti of Queens College at City University of New York and Paul W. Ewald of the University of Louisville argue that in the phenomenon of rapid evolution there is nothing exceptional. Rapid change is just the result of a response to intense changes in nature, thanks to which the body learns to resist external factors. However, not everything is so simple: in order to ensure rapid evolution, the genome should initially contain a sufficient number of variations of one or another feature.
Lahti adds that for people, social selection is gradually becoming paramount. In particular, the presence of hostile groups, coupled with the need for close intra-group cooperation, has led to the fact that the social life of a person has become more complex by several orders, and its brain has become large and complex. Scientists do not know in which form the relations between the ancient black Europeans and the settlers from the East developed: probably, as in any society, they fought, and exchanged, and even crossed with each other. All that we can judge is the oppression of some features and the formation of others, the imprints of which have been preserved in the anatomy and genes of fossil remains.
The genes of both dark and light skin have not disappeared to this day. Nature seldom is wasteful: the pale skin of the northerners helps them partially endure vitamin D deficiency, while the dark skin of southerners also is an adaptation to the hot, sunny climate. Since climatic changes occur annually, even now it is impossible to say with certainty how the appearance of Europeans will change in some 500 years.
Human evolution has never ceased – this is the essence of natural selection. It can not be said that in general, as a species, we are developing in a certain direction: people of the future will not be universally creatures with a big head and skinny body, despite the fact that this image is so fond of cheap science fiction. We are from generation to generation adapting to external factors, such as diseases, climate change and even the transformation of social structures. Probably, in the future, a person will master science and technology so that he can fully control his development and modify the body of his own volition. But this is a completely different matter.