Humans are well—armed predators

What do we know about human evolution

Life originated on Earth 4.5 billion years ago. These standards — quite young. Who were our ancestors and how they have changed? Which way now moving evolutionary process and what would happen if we all will make robots and artificial intelligence? PostNuke told anthropologist Stanislav Drobyshevsky.

From apes to Homo Sapiens

— When and how did the first people?

— Members of the species Homo appeared about 2.5–3 million years ago in East Africa. It was a long and complex evolutionary path from the first primatomorpha (66 million years ago), Dolgopyatova (56 million years ago) and the great apes (26 million years ago). The one we call Homo Sapiens, only one of the members of the genus, alongside Homo neanderthalensis (Neanderthals), Homo erectus (Homo erectus), Homo ergaster (working man), and others.

About 50 thousand years ago, our direct ancestors left Africa and populated the European continent, and later the entire planet.

— Why there is only one kind of person?

Long time, at least five species of Homo at the same time lived on the planet, and why it remains only a "reasonable person" is not known. Probably sapiens were stronger competitors: some demographic swallowed, the other destroyed. It always happens, when one large species occupies a large part of the territory.

People is a well-armed predators. You're not surprised why one species of giraffe. In the Pliocene, there were many different types, but now only Giraffa camelopardalis. The same applies to horses or aardvarks.

— When the person was last anatomical changes?

— In fact, they happen all the time. But we noticed, it will take time.

The first noticeable change was in the era of humanoid monkeys about 25 million years ago, when fewer fur and no tail. The last significant transformations took place in the interval from 300 to 50 thousand years ago: increased brain volume, shrank the neck, forehead became more prominent. In addition, decreased face, teeth and brow creases. The body gradually became less massive and more high.

However, due to various conditions anatomical characteristics has varied at different speeds — this is mosaic evolution. For example, when early humans climbed down from the trees, they quickly began to change stop, and when Australopithecus Homo appeared, rapidly became more complex and increase the brain.

However, the last 25 thousand years the process has gone in the opposite direction: the brain become "dry". But it's not scary, at some point, the motion vector may change. The color of the skin of the apes millions of years was bright, the Australopithecines and early Homo darkened, and 7 thousand years ago, some members of the species once again became bright.

Africa — the cradle of humanity

Anthropologists have agreed that the settlement was in one place, and not different? That is from Africa? Or is it still a debatable issue?

— There are anthropologists, archaeologists who have another point of view, but is rather an exception. Today these genetics, morphology, and linguistics suggests that our ancestors came from Africa. From there you can trace a direct sequence — the dark wood of the apes to modern man.

About the Asian, European or even American homeland talked until it was too small finds. It is now clear that people in Europe appeared only 1 million 300 years ago, in Australia, less than 50 thousand years ago, and in the U.S. later. And it was already sapiens. And in Africa, have found the remains of nakalipithecus and different species of Homo. Laboratory of genetic research paints the same picture.

— Is the genetic molecule can be kept so long?

— DNA is a large, complex polymer, and therefore kept very normal. The most ancient DNA isolated from people, 800 thousand years. Of course, these are fragments, but it is much to learn.

Analyzing the genomes of modern people who live in different parts of the planet, build their family tree to ancestors sapiens, and even individual genes to determine the relationship with finches or bacteria, because all living organisms have a common ancestor, the so — called Onion (the first cell).

If we talk about Africa, it contains all the genetic diversity. And you can see how from a single population in the Eastern part of the continent stretches a link to the representatives of the Eastern-Equatorial branch (aborigines, Melanesians, Papuans), and then to the Eurasian Union, which later was divided into European, Asian and American.

Please note, this does not mean that the modern inhabitants of Africa, the ancestors of all people. Because they have evolved as many times as other people, accumulating their mutations.

— What changes have occurred in the environment of the last 100 thousand years ago and how it has influenced evolution?

— 100 thousand years is a long interval, a lot of things happened. For example, the climate was changing in different parts of the world became much colder, too hot. It is characteristic that the periods of glaciation was mostly short-term. But people are faced with a serious cold, only the last 40 thousand years, when it came out of his cradle.

Just in Africa this climate swings were not. This is what allowed Homo sapiens to survive and to evolve further, unlike, for example, from the Neanderthals, who lived in cold climates and gradually died out.

If we all came from Africa, I suppose, we should all be black? How is it Negroid, Caucasian, Mongoloid and Australoid?

— Race arose because we long ago came out of Africa. Agree, 40-50 thousand years and can be a little switch. Although races in the form in which we know it, was formed about 12 thousand years ago. And some (matinee) and later — 4 thousand years ago.

The causes were different. The simplest is the adaptation to changing conditions: humidity, air temperature, insolation. Some signs were more favorable in the current climate. In particular, skin color adaptation to sun exposure, light tint appeared quite late — about 7 thousand years ago.

Their influence was assisted migration, isolation, cross-breeding. But sometimes the changes are not determined, as the color of the hair, for example. Globally there is no difference, bright or dark it is, he still has no effect. Such accidents or genetic-automatic processes, just chase signs here and there.

It is important to understand that the races were before, from Australopithecus or monkeys, even the buttercups. 12 thousand years ago, there are those that we recognize, but all the time they had also changed. 20 thousand years ago combinations of signs were other people lived with a shortened jaw and dark skin, today there are none. Probably after 100 thousand years race will be others, and what we don't know.

A wide range of variation — the key to the future survival

— How modern medicine affects natural selection, he still exists?

— Natural selection does not stop. We remain dependent on air temperature, insolation and other factors.

Yes, medicine is in some sense affected. But if the doctors of the man survived and was able to leave offspring, so all right. Harmful signs from the point of view of evolution are not transmitted. For example, congenital astigmatism and weak musculature do not prevent a modern person from living and successfully reproducing. But in the Paleolithic, such comrades would not have lasted long.

Today, the so-called destabilizing selection is more active, when the range of variability increases (one of the forms of natural selection). And the range of variability is the key to future survival. In other words, what seems to be pathology today may play into your hands later. Once all monkeys had long hair, but over time it turned out that the best option was to have a short one. Accordingly, those individuals who were born with a small amount of wool survived, although at first they looked strange in the eyes of their relatives.

Perhaps, in humans, the reduction of some organs or systems after centuries will be a useful sign - for example, poor eyesight or weak muscles. In early Homo, in particular, a decrease in the chewing muscles allowed the brains to grow.

— Does evolution also not stop in the human population, as well as natural selection?

- of course. Evolution is a differentiated transfer of genes to the next generation, so it physically cannot stop. In each next generation, the frequencies of genotypes differ from the previous ones: mutations occur, recombinations occur in all directions.

Although we know of cases of megastabilizing selection, when the coding DNA of a species has not changed for more than 230 million years. For example, Triops cancriformis (summer shield) as it was, it remains so. But this is a unique case.

— Is evolution slowing down or continuing at the same pace?

— To be honest, we don't know. How to measure the speed of evolution? The number of mutations or nucleotide substitutions? Evolution is a slow process, stretched over many centuries, so even ancient DNA does not save us, we do not have such data from protosapiences. We can build a phylogenetic tree and a molecular clock, but they will reflect only the sequence of changes, and not the dating of specific mutations.

Probably the mutation rate is the same. But natural selection has probably decreased on average due to the development of culture and the achievements of civilization. It would be more correct to say that the stabilizing and driving selection has become less rigid, but the destabilizing one is active. This is a different direction of selection, but also selection, as already mentioned.

— Can evolution go backwards? What are the chances of turning back into the same monkey?

— Easily. Another thing is that we will not turn into the same monkey: other conditions. To rewind exactly to the same point, you will have to rewind the entire ecosystem, and this is impossible. But humanity can degrade easily and naturally. For example, our brain is shrinking — why can't we grow hair again? Mammoths have overgrown: from almost bald tropical elephants, they have turned into furry ones again.

Your little finger is a gift for an anthropologist

— The average person gets the impression that a bone fragment can be used to find out a person's age, gender, hobbies and even the cause of death. Is that true?

— Yes, indeed, you can learn a lot from one finger. I even have a lecture "The evolution of the left little finger": the phalanx of the left little finger has been preserved from the Denisov man, from which it was possible to isolate DNA and understand the microstructure of bones and the eye color of the person to whom the finger belonged. But even only one morphological feature can tell the approximate parameters of the host and its evolutionary stage.

Pelvic bones or teeth provide even more information. At the same time, it is worth remembering that science has a large arsenal and many possibilities, but they are not unlimited. It will not be possible to determine the cause of death if it has not affected the bones in any way.

— Where is anthropology going?

— Over the past 10 years, paleoproteomics has been developing — a field of molecular science in which the technology of sequencing based on proteomics is used to identify species and evolutionary relationships of extinct taxa. 

But even well-known methods, thanks to new technologies, get a second wind. Previously, morphology was measured with a compass, but now there is 3D morphometry, microtomography has appeared. How do I know if a Neanderthal was talking or not? It is difficult by external parameters, but it is possible by microtomography of the hyoid bone.

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