Biological evolution is defined as any genetic change in a population that has occurred over several generations. These changes can be small or large, very noticeable or not significant.

For an event to be considered an example of evolution, changes must occur at the genetic level of the species and be passed on from one generation to the next. This means that , or more specifically, the alleles in the population are changed and passed on. These changes are noted in the (pronounced physical traits that can be seen) of the population.

A change in the genetic level of a population is defined as a small-scale change and is called microevolution. Biological evolution also includes the idea that all living organisms are related and can be descended from one common ancestor. This is called macroevolution.

What is not related to biological evolution?

Biological evolution does not define the simple change of organisms over time. Many living things experience changes over time, such as loss or increase in size. These changes are not considered examples of evolution because they are not genetic and cannot be passed on to the next generation.

Evolution theory

How does genetic diversity occur in a population?

Sexual reproduction can create favorable combinations of genes in a population or remove unfavorable ones.

A population with more favorable genetic combinations will survive in its environment and reproduce more offspring than individuals with less favorable genetic combinations.

Biological evolution and creationism

The theory of evolution has caused controversy since its inception, which continues to this day. Biological evolution contradicts religion in regards to the need for a divine creator. Evolutionists argue that evolution does not address the question of whether God exists, but attempts to explain how natural processes occur.

This, however, does not avoid the fact that evolution is contrary to some aspects of certain religious beliefs. For example, the evolutionary account for the existence of life and the biblical account of creation are quite different.

Evolution assumes that all life is connected and can be traced back to one common ancestor. A literal interpretation of biblical creation suggests that life was created by an omnipotent supernatural being (God).

However, others have tried to combine the two, arguing that evolution does not rule out the possibility of God, but simply explains the process by which God created life. However, this view still contradicts the literal interpretation of creativity presented in the Bible.

For the most part, evolutionists and creationists agree that microevolution does exist and is visible in nature.

However, macroevolution refers to a process of evolution that is at the species level, and where one species evolves from another species. This contrasts sharply with the biblical view that God was personally involved in the formation and creation of living organisms.

So far, the evolution/creationist debate is ongoing, and it seems that the differences between the two views are unlikely to be resolved any time soon.

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The historical development of wildlife occurs according to certain laws and is characterized by a combination of individual features. The advances in biology in the first half of the 19th century served as a prerequisite for the creation new science- evolutionary biology. She immediately became popular. And she proved that evolution in biology is a deterministic and irreversible process of development of both individual species and their entire communities - populations. It occurs in the biosphere of the Earth, affecting all its shells. This article will be devoted to both the study of the concepts of a biological species, and

History of development of evolutionary views

Science has gone through a difficult path of forming worldview ideas about the mechanisms that underlie the nature of our planet. It began with the ideas of creationism expressed by C. Linnaeus, J. Cuvier, C. Lyell. The first evolutionary hypothesis was presented by the French scientist Lamarck in his work "Philosophy of Zoology". English researcher Charles Darwin was the first in science to suggest that evolution in biology is a process based on hereditary variability and natural selection. Its basis is the struggle for existence.

Darwin believed that the appearance of continuous changes in biological species is the result of their adaptation to the constant change of environmental factors. The struggle for existence, according to the scientist, is a set of interconnections of the organism with surrounding nature. And its reason lies in the desire of living beings to increase their numbers and expand their habitats. All of the above factors and includes evolution. Biology, which grade 9 studies in the classroom, considers the processes of hereditary variability and natural selection in the section "Evolutionary Teaching".

Synthetic hypothesis of the development of the organic world

Even during the lifetime of Charles Darwin, his ideas were criticized by a number of such famous scientists as F. Jenkin and G. Spencer. In the 20th century, in connection with the rapid genetic research and the postulation of Mendel's laws of heredity, it became possible to create a synthetic hypothesis of evolution. In their writings, it was described by such as S. Chetverikov, D. Haldane and S. Ride. They argued that evolution in biology is a phenomenon of biological progress, which has the form of aromorphoses, idioadaptations affecting populations of various species.

According to this hypothesis, the evolutionary factors are the waves of life, and isolation. Forms of the historical development of nature are manifested in such processes as speciation, microevolution and macroevolution. The above scientific views can be represented as a summation of knowledge about mutations, which are the source of hereditary variability. As well as ideas about the population as a structural unit of the historical development of a biological species.

What is an evolutionary environment?

This term is understood as biogeocenotic. Microevolutionary processes occur in it, affecting populations of one species. As a result, the emergence of subspecies and new biological species becomes possible. Processes leading to the appearance of taxa - genera, families, classes - are also observed here. They belong to macroevolution. Scientific research by V. Vernadsky, proving the close relationship of all levels of organization of living matter in the biosphere, confirms the fact that biogeocenosis is an environment for evolutionary processes.

In climax, that is, stable ecosystems, in which there is a large diversity of populations of many classes, changes occur as a result of coherent evolution. in such stable biogeocenoses are called coenophilic. And in systems with unstable conditions, uncoordinated evolution occurs among ecologically plastic, so-called cenophobic species. Migrations of individuals of different populations of the same species change their gene pools, disrupting the frequency of occurrence of different genes. So says modern biology. The evolution of the organic world, which we will consider below, confirms this fact.

Stages of development of nature

Scientists such as S. Razumovsky and V. Krasilov proved that the pace of evolution underlying the development of nature is uneven. They represent slow and almost imperceptible changes in stable biogeocenoses. They accelerate sharply during periods environmental crises: man-made disasters, melting glaciers, etc. About 3 million species of living beings live in the modern biosphere. The most important of them for human life is studied by biology (Grade 7). The evolution of Protozoa, Coelenterates, Arthropods, Chordates is a gradual complication of the circulatory, respiratory, and nervous systems of these animals.

The first remains of living organisms are found in the Archean sedimentary rocks. Their age is about 2.5 billion years. The first eukaryotes appeared at the beginning Possible variants of the origin of multicellular organisms explain scientific hypotheses phagocytella I. Mechnikov and gastrea E. Getell. Evolution in biology is the path of development of wildlife from the first Archean life forms to the diversity of flora and fauna of the modern Cenozoic era.

Modern ideas about the factors of evolution

They are conditions that cause adaptive changes in organisms. Their genotype is the most protected from external influences(conservative gene pool of a biological species). Hereditary information can still change under the influence of genes. It was in this way - by acquiring new signs and properties - that the evolution of animals took place. Biology studies it in such sections as comparative anatomy, biogeography and genetics. Reproduction, as a factor in evolution, is of exceptional importance. It ensures the change of generations and the continuity of life.

Man and the biosphere

Biology studies the processes of the formation of the Earth's shells and the geochemical activity of living organisms. The evolution of the biosphere of our planet has a long geological history. It was developed by V. Vernadsky in his teachings. He also introduced the term "noosphere", meaning by it the influence of conscious (mental) human activity on nature. Living matter, which is included in all the shells of the planet, changes them and determines the circulation of substances and energy.

The offspring of living beings are very similar to their parents. However, if the habitat of living organisms changes, they too can change significantly. For example, if the climate gradually becomes colder, then some species may acquire more and more dense wool from generation to generation. This process is called evolution. Over millions of years of evolution, small changes, accumulating, can lead to the emergence of new plant and animal species that differ sharply from their ancestors.

How does evolution take place?

At the heart of evolution is natural selection. It happens like this. All animals or plants belonging to the same species are still slightly different from each other. Some of these differences allow their owners to better adapt to the conditions of life than their relatives. For example, some deer especially quick legs, and every time he manages to escape from the predator. Such a deer is more likely to survive and have offspring, and the ability to run fast can be passed on to its cubs, or, as they say, be inherited by them.

Evolution has created countless ways to adapt to the difficulties and dangers of life on Earth. For example, seeds horse chestnut over time, they acquired a shell covered with sharp spines. The thorns protect the seed as it falls from the tree to the ground.

What is the rate of evolution?

Previously, these butterflies had light wings. They hid from enemies on tree trunks with the same light bark. However, about 1% of these butterflies had dark wings. Naturally, the birds immediately noticed them and, as a rule, ate them before others.

Usually evolution proceeds very slowly. But there are times when a species of animal undergoes rapid changes and spends not thousands and millions of years on it, but much less. For example, some butterflies have changed their color over the past two hundred years in order to adapt to the new conditions of life in those parts of Europe where many industrial enterprises have arisen.

About two hundred years ago in Western Europe began to build coal-fired factories. The smoke from the factory chimneys contained soot, which settled on the trunks of the trees, and they turned black. Now the bright butterflies are more noticeable. And a few previously dark-winged butterflies survived, because the birds no longer noticed them. From them came other butterflies with the same dark wings. And now most of the butterflies of this species that live in industrial areas have dark wings.

Why are some animal species going extinct?

Some living beings are unable to evolve when their environment changes drastically and die out as a result. For example, huge hairy animals that look like elephants - mammoths, most likely died out because the climate on Earth at that time became more contrasting: it was too hot in summer and too cold in winter. In addition, their numbers have declined due to increased hunting for them. primitive man. And after the mammoths, the saber-toothed tigers also died out - after all, their huge fangs were adapted to hunt only large animals like mammoths. Smaller animals were not available for saber-toothed tigers, and, left without prey, they disappeared from the face of our planet.

How do we know that man also evolved?

Most scientists believe that humans evolved from tree-dwelling animals similar to modern apes. The proof of this theory are some features of the structure of our bodies, allowing, in particular, to suggest that once our ancestors were vegetarians and ate only the fruits, roots and stems of plants.

At the base of your spine there is a bone formation called the coccyx. This is all that's left of the tail. Most of the hair that covers your body is just soft fluff, but our ancestors had much thicker hair. Each hair is equipped with a special muscle and stands on end when you get cold. So it is with all mammals with hairy skin: it retains air, which does not allow the heat of the animal to escape.

Many adults have wide outer teeth - they are called "wisdom teeth". Now there is no need for these teeth, but at one time our ancestors chewed with them the hard plant food they ate. The appendix is ​​a small tube attached to the intestines. Our distant ancestors, with its help, digested plant foods that were poorly absorbed by the body. Now it is no longer needed and is gradually getting smaller and smaller. In many herbivores - for example, rabbits - the appendix is ​​​​very well developed.

Can humans control evolution?

Humans drive evolution some animals are over 10,000 years old. For example, many modern breeds of dogs, in all likelihood, descended from wolves, packs of which roamed near the camps of ancient people. Gradually, those of them that began to live with people evolved into a new kind of animal, that is, they became dogs. Then people began to specially raise dogs for certain purposes. This is called selection. As a result, there are over 150 different dog breeds in the world today.

• Dogs that could be taught different commands, like this English Sheepdog, were bred to herd cattle.
• Dogs that could run fast were used to chase game. This greyhound has powerful legs and runs with huge leaps.
• Dogs with a good sense of smell were bred specifically for tracking down game. This smooth-coated dachshund can rip rabbit holes.

Through natural selection, as a rule, proceeds very slowly. Selective selection allows you to dramatically accelerate it.

What is genetic engineering?

In the 70s. 20th century scientists have invented a way to change the properties of living organisms by interfering with their genetic code. This technology is called genetic engineering. Genes carry a kind of biological cipher contained in every living cell. It determines the size and appearance every living being. With the help of genetic engineering, it is possible to breed plants and animals that, say, grow faster or are less susceptible to any disease.

How did the settlement of human ancestors occur? globe? Why did the tree-dwelling primates descend to the ground and stand on two legs, while the black population of Africa is the only purebred Homo sapiens? He tried to answer these questions in his lecture, held in Gorky Park as part of the Open Environment project, candidate biological sciences, Associate Professor, Department of Anthropology, Faculty of Biology, Moscow State University named after M.V. Lomonosov, scientific editor of the Anthropogenesis.ru portal Stanislav Drobyshevsky.

The origin of man can be counted from different moments - say, from the appearance of primates (about 65 million years ago), but it is easiest to do this from the moment of bipedalism. Upright walking has been thought about since the 19th century, when it became clear that man, one way or another, descended from primates, but the intermediate links of evolution, semi-quadrupedal-semi-erect walking, eluded researchers for a long time.

From primate to human

Only literally in the last ten years have bones of these creatures been found. On the this moment the oldest of them is the Sahelanthropus of Chad, whose skull and lower jaws, as well as teeth, were found in the Republic of Chad. They are about 7 million years old.

Then in this territory there were savannahs, lakes and thickets of bushes. At this time, the climate was drying up, and the primates that lived in the tropical forests that covered most of Africa experienced some difficulties.

They had three options in this situation. Firstly, to die out, because the forests were disappearing and there was nowhere to go. Most primates have successfully followed this fate, and now we have their bones. The second option is to stay in the forests, because not all of them have disappeared (now there are quite a lot of tropical forests in Central and West Africa). Today, two species of chimpanzees and gorillas live in them. The third option was to adapt to the new environment, which some primates did.

But on open area there were all sorts of problems. The ancestors of these creatures climbed trees, but there are no more trees in the savannahs. There was a problem of thermoregulation, protection from predators, I had to eat in a new way. All this led to the fact that they descended to the ground, standing on two legs.

Of course it's not the only one possible variant, because the baboons also descended from the trees around this time and continued to walk on all fours. But our ancestors were larger than baboons, they had a pre-adaptation to the vertical position of the body, and it turned out to be easier for them to stand on two legs, freeing two hands.

This, however, does not mean that they immediately began to do something useful with these hands. In the next few million years, hands were used for peeling grain, picking fruits - not very intellectual pursuits. These first upright creatures (including the Sahelanthropus) were, in fact, bipedal monkeys.

Their head was small, the brain was placed in it somewhere 100 grams less than that of a chimpanzee, and the muzzle was very large. In addition to walking upright, they had only two progressive signs: the lower position of the foramen magnum on the skull, connecting the brain to the spinal cord, and small fangs.

Small fangs - very important feature, because he led to the fact that they became, roughly speaking, kinder. Monkeys need large fangs in order to scare someone, since they are herbivorous and do not gnaw anyone with them. But if a baboon bares its teeth, which it has more than a leopard, then this is impressive. When the Sahelanthropus bared his teeth (which, of course, he had more than ours, but much less than those of a chimpanzee), this was not very impressive.

As a result, he had new ways of expressing his "wealthy inner world", feelings. The release of hands was the first step towards the emergence of rich gestures, facial expressions and speech (at that time, of course, no speech arose, but there were the first prerequisites for it).

It is interesting that, most likely, bipedalism arose not once, but several times. At a slightly later time, about 6 million years ago, Orrorin lived in East Africa. He has been touted in popular culture as the "millennium man" since he was discovered in 2000. There was no whole skull left of him, only fragments, but the femurs remained. This bone is directly related to the type of movement, and it shows that Orrorin was more or less upright.

Researchers have even suggested that Orrorins were more upright than later Australopithecus. It looked strange - it turns out that at first our ancestors developed, then degraded, and then developed again. More recently, in 2014, a new study of orrorin femurs was done, which showed that, despite progressive signs, most of of signs makes them related to more ancient four-legged primates that jumped through the trees 10 million years ago. There are also Ororrin teeth (the teeth are generally well preserved), and these teeth, although slightly smaller than those of Sahelanthropus, are much larger than ours.

Ardipithecus and Australopithecus

After a while, ardipithecus appear. Currently, two species are known: Ardipithecus ramidus (lived 4.5 million years ago) and Ardipithecus kadabba (more ancient, lived more than 5 million years ago). More ancient ones are little studied due to not a large number remains. Ardipithecus ramidus is much better studied, since an almost complete skeleton was found, about which will be discussed. This skeleton was discovered in 1994, but until 2006, scientific work on it was not published, since it was found in a very damaged state and reconstructed all this time.

Ardipithecus ramidus is a remarkable intermediate stage between ape and man. In fact, this is the very “missing link” that has been dreamed of since the time of Darwin, and now it has finally been found. Its signs are almost 50 to 50 belong to both the monkey and the man. For example, his hands are almost to the knees, and on the foot thumb protruding, about the same as on our hand.

The weight of his brain is 400 grams, like a chimpanzee (for comparison, modern man- 1400). The structure of his skull is the same as that of a monkey, and the only thing that distinguishes him from a monkey is small fangs and a complex of bipedal locomotion. But along with these primitive features, there are also advanced ones.

He has a fairly developed pelvis. The pelvic bones in humans are low and wide, adapted to walking on two legs, while in monkeys they are narrow and high, and their whole body is elongated. In Ardipithecus, everything is strictly in the middle - its height and width are approximately the same. And it should be noted the perfect structure of his foot. Although the thumb is protruding, it has longitudinal and transverse arches, which are not needed for anything other than upright walking. At the same time, Ardipithecus climbed trees great, most likely, he could run on all fours with support on his palm and could walk on two legs.

After that, evolution could go anywhere. Man's ancestors could have gone back to the forests that were nearby, they could have ended up in the savannah, moving on all fours like baboons, or they could have walked on two legs, and, fortunately for us, they came out on two legs. Where Ardipithecus ramidus lived, there was a kind of park community, when tree crowns cover about 40 percent of the territory. You can’t jump from branch to branch indefinitely, sometimes you have to go down to the ground. On the other hand, trees stand quite often, and you can climb a tree.

At a later time, the savannas expanded, became more open, and at this time a group of australopithecines appeared. All of them lived in Africa, were completely bipedal and below the head looked almost like people. Almost, but not quite, because on their foot the big toe is slightly, but separated from the rest. Their hand was approximately the same proportion as ours, but in terms of the structure of individual bones, it looked more like a monkey. They did not make stone tools.

Their head was, by and large, that of a monkey. The mass of the brain of Australopithecus was 400-450 grams, the most gifted - 500 grams, that is, approximately like a chimpanzee. The growth of most Australopithecus ranged from 1 to 1.5 meters, and if we calculate not the absolute size of the brain, but relative to body weight, it turns out that they were still smarter than chimpanzees, but this, apparently, did not particularly manifest itself until some that time.

The time came about 2.5 million years ago, when the climate became even drier and colder (it is worth remembering, however, that this is Africa, that is, colder by African standards). Australopithecus split into two branches. One of them was paranthropus, or massive australopithecines. They were distinguished by a very powerful chewing apparatus, huge jaws and teeth, and when scientists found the first representative, they called it the "nutcracker".

They ate, apparently, vegetation, that is, they were vegetarians. Having existed for a million years, they died out. But in that million years they flourished, and during that time they were the main species of large primates on the African savannah. Their remains are in huge number(at the moment, several thousand have already been found) - many times more than, say, the ancient leopards and lions that lived at the same time.

First people

Simultaneously with these massive australopithecines, the first people appeared - the genus Homo. You should not think that they looked like a modern person, since Homo is just a genus. Homo Habilis, a skilled man, did not differ much in structure from Australopithecus. His height was still the same 1.5 meters, there was a lot of primitive in the structure of the hand and foot, while the brain, although it was not prohibitively large, but its mass was significantly larger than that of Australopithecus, not 450-500 grams, but 600 -700 and even more.

It's already a lot. For a modern person, this is a minimum - there is the concept of the "brain Rubicon", the boundary that separates a person from a monkey by brain mass, and it is 750-800 grams. It also distinguishes Australopithecus from a skilled person, and it also distinguishes modern mentally normal people from abnormal, microcephalic people who have some kind of birth defects and whose brain does not grow. For example, a person can have a brain weighing 300 grams - less than that of a chimpanzee, and he will live, but he will not be able to think.

Significantly, the first stone tools that we find in Africa appeared about 2.5 million years ago. The oldest of them were found at the Gona site in Ethiopia, and just a month ago, information came that more ancient tools were found at the Lomekvi excavation site, also in Africa, whose age is 3.3 million years. There is no scientific publication regarding this find yet, so a period of 2.5 million can be considered reliable.

The first stone tools were very primitive. They were a pebble culture - a pebble or any large cobblestone was split in half and trimmed with two or three blows. But no matter how primitive they are, they are difficult to make. Even the most primitive tool of a skilled man cannot be made by modern man. I watched how archaeologists with great experience tried to repeat the tools of ancient people, and at that time they reached the level of pithecanthropes in this matter.

All this suggests that by the time a skilled person appeared, coordination of movements had grown, there were enough brains to plan their actions - the repeatability of the types of tools suggests that they had a plan, they knew what they wanted to get.

Progress did not stand still, and about 1.5 million years ago, again in East Africa, the first evidence of people using fire appeared. Even earlier, 1 million 750 thousand years ago, the first dwellings appeared. This word sounds proud, but in fact they were a kind of wind barrier made of branches crushed by stones. Normal dwellings appeared much later in the north, in Eurasia.

About 2 million years ago, people finally went beyond Africa. Currently the most ancient famous people outside of Africa lived on the territory of modern Georgia. It is clear that Georgia is not connected with Africa, people did not teleport there, and their traces must be somewhere along the way, but so far they have not been found. In terms of development, they were the same as in Africa, they had stone tools, but they were very primitive, with a small brain (700-800 grams), small stature (1.4 meters) and a large face with a heavy brow .

Most likely, these first exits from Africa ended sadly. But about 1.5-1.2 million years ago, people settled in the entire tropical zone: Africa, the Mediterranean and Asia - up to Java. Along the way of this settlement, they evolved into a new species - Homo erectus Homo Erectus. Of course, bipedalism arose much earlier, but for Eugene Dubois, who in late XIX century found the first bones of this species in Java, it was the most ancient erectus.

This species is more human-like than its predecessors. The mass of their brain is about 1 kilogram. They formed a new culture - the Acheulean (it appeared in Africa, and then spread to other places). They made stone axes - large tools, processed from all sides. Moreover, later stone axes had a very symmetrical shape, even too symmetrical, since this was not necessary in terms of functionality.

Some archaeologists believe that this is evidence of the birth of art - when a stone is beautiful, it is pleasant to look at it, you get aesthetic pleasure from it. There are finds of axes, in the center of which there was a red inclusion, and Homo erectus did not knock it down, but left it on purpose. Or there was a fossil shell in the rock, and he did not destroy it, but specially designed it into a handle.

Photo: Kenneth Garrett / Danita Delimont / Global Look

At first they settled mainly along the coast of the Indian Ocean, they were people who collected what the sea threw out. When they came from Africa, on the right was the ocean, on the left - mostly desert. Ahead of a lot of tasty things, behind - hungry relatives. In this situation, they settled very quickly. Calculations show that in 5 thousand years they could "run" from Africa to Java. Given the inaccuracy of the dating methods that we have, we see that they appeared almost immediately and everywhere. The same thing then happened repeatedly, they left Africa not once, but many times.

Approximately 500 thousand years ago, a new species appeared - Homo heidelbergensis, the Heidelberg man (in honor of the German city of Heidelberg, where the first jaw of a representative of this species was found at the beginning of the 20th century). It is now clear that they lived almost everywhere in Africa and Eurasia. The mass of their brain was comparable to ours - 1300 grams, and some of them even 1450, which is comparable to a modern person.

It is believed that they were the first to enter the area with temperate climate where winter happens. However, in 2014, earlier traces of Homo antecessor people were found in England, but how long they lingered there is unclear. Homo heidelbergensis built more or less normal dwellings in the form of huts, and quite a decent size - up to nine meters long and four meters wide, sometimes with several chambers.

Around 300,000 years ago, people often begin to use fire.

Indigenous Eurasians

130 thousand years ago, those Homo heidelbergensis that lived in Europe gradually turned into Neanderthals. Strictly speaking, there is no boundary between Homo heidelbergensis and Homo neanderthalensis, but the classical Neanderthals, who lived 70 thousand years ago, differ significantly from their predecessors. They have a very large brain - weighing an average of 1400 grams, or even 1500, that is, more than our average.

Their faces were very large and heavy, their noses wide and very massive: broad shoulders, powerful barrel-shaped rib cage slightly shortened arms and legs. These are the so-called "hyperarctic" proportions, adapted to the cold climate - at this time, alternations of glacial and interglacial periods began. True, they did not go into very cold places, but they did not use fire too often. When it's minus 10 all winter and you have to live without fire, it's not very healthy, so their body proportions were adjusted to keep warm. It's the same with modern people. If we look at people from Africa, they will all be stretched out like sticks - so the body cools down faster. Those in the north - the Eskimos, the Chukchi - will, in fact, be square.

Neanderthals appeared in Europe - this is its indigenous population. From there they settled in the Middle East and further into Asia, approximately to Altai. In the Middle East, they met with Homo sapiens, Homo sapiens, which originated in Africa (not everyone left there, and those who remained gradually turned into reasonable people).

But in East Asia it is not clear who lived. Just a few years ago, an analysis was made of the remains of a man found in Altai in Denisova Cave. It turned out that his DNA (from the teeth and phalanx of the finger) differs from the DNA of a modern person, and from the DNA of a Neanderthal, which was deciphered in 2001. It turned out that some Denisovans lived in East Asia.

We know most of the fossil people from their skeletons, and not from their DNA, but we know the Denisovans from their DNA, but we don’t know who they looked like, because there are only two of their teeth and a phalanx of a finger for study. The teeth of this person were large, the phalanx was thick, and on the basis of this it can be assumed that they were large, although the size of the teeth is not strongly related to the size of the body.

However, how DNA is translated into appearance is partially known to scientists. We do not know how the nose or lips are encoded in it, but we know that the Denisovans had dark skin, dark hair and dark eyes. These genes were also considered in the case of Neanderthals. It turned out that their skin was light, their hair was both dark and light, and their eyes were also light. Interestingly, Neanderthals had blond hair in a different way than ours. This feature can be provided by different mutations - the genes encoding the dark pigment can be "broken" in different ways. In European Homo sapiens, they are “broken” in one way, in Neanderthals in another way, and, say, in modern Melanesians in a third way.

Photo: Werner Forman Archive / Global Look

The Neanderthals used the tools of the Mousterian and Mykok cultures (there were others, but these are the most important). These cultures were more advanced than the Acheulean, Pithecanthropus, and Homo erectus. The tools in them were made by beating off flakes. A blank stone was taken, fragments were beaten off from it, which were then trimmed. The variety and number of tools has grown, while the labor costs for their manufacture have decreased. If earlier it was possible to make one ax from one blank, now a bunch of flakes were made from it, which means a lot of tools - pointed, side-scrapers and various others.

However, Neanderthals were rather backward compared to us. Until recently, their backwardness, apparently, was even exaggerated. It was believed that they were almost entirely predators, but a few years ago, an analysis of tartar from a Neanderthal tooth was carried out, and it turned out that they also ate plant foods.

The most interesting thing is that the Belgian Neanderthals were found with grains of starch of a specific form - apparently, they cooked porridge from barley. How they cooked it is not very clear, because they did not have ceramics, but ethnography shows how this can be done. For example, in a pit, in a basket, in a leather bag, in the stomach of a bison - if you pour water into it and throw hot stones, the water boils quickly and you can cook porridge. Many nations before the 19th century did just that.

Moreover, particles of chamomile and yarrow were found on the teeth of a woman from the Cidron Cave in Spain. Few people would think of chewing these plants just like that, because they are bitter, this suggests that they had medicine, since these plants are medicinal. Another piece of evidence of this kind comes from the Shanidar cave in Iraq. When is the burial ancient man they began to analyze it, it turned out that the pollen spores of the plant lie in heaps in the grave (that is, they were precisely the flowers thrown into it), and all this is exclusively medicinal plants.

Homo heidelbergensis began to use the so-called "sanitary burials". When a person dies and lies under their feet, it is unpleasant, so they took him, dragged him 500 meters and threw him into deep hole. There is a rock with a 16-meter crack, into which a bunch of people were thrown, and now we have such a wonderful layered “pie” of bones that have been digging since the 70s and still have not finished yet. Nearly 2,000 bones have already been found.

Photo: Caro / Oberhaeuser / Global Look

Mettmann, North Rhine-Westphalia, Germany - The Neanderthal Museum in Mettmann

Neanderthals already had real burials. Their specificity lies in the fact that more than one person never fit into one grave, always in the same position - the body is crouched, on its side, in order to dig less. They sprinkled the corpse with literally 20 centimeters of earth so that it would not stick out from the outside. Most importantly, grave goods are never found in the graves, there are no decorations, the body is not sprinkled with ocher, no animal bones - just a body, that's all. At the same time, the Neanderthals knew that someone previous was buried nearby - the graves are oriented mutually, go one after the other, in parallel.

But the postulate about the lack of fantasy in these people in recent times has also been questioned. Evidence of Neanderthal art has been found - this year information was published on the study of bird claws from the Krapina site in Croatia. There were found the claws of birds of prey, such as the white-tailed eagle, worn and lying in a characteristic order in a pile - apparently, it was a necklace of claws. Even earlier, pendants made of teeth and other similar things were found. But all the same, in this regard, Neanderthals are disastrously behind reasonable people.

Homo sapiens

Homo sapiens appeared in Africa between 200,000 and 50,000 years ago. In this interval there are finds of the remains of what seems to be a reasonable person, but at the same time not quite. If one such comrade is placed next to modern people, one might notice something strange, but if a group of modern people is placed opposite a group of ancient people, the differences will be clear. For example, not all proto-sapiens have a chin, their eyebrows are powerful, their heads are large. And so, in the interval from 200 to 50 thousand years ago, all this came to a more or less modern state.

About 50 thousand years ago, they almost did not differ from us. This does not mean that evolution, as some people think, has stopped. Just for such a time, evolutionary changes simply could not manifest themselves. As they walked, the teeth were getting smaller, the brow was getting smaller, the bones of the skull were getting thinner, but these differences are very small. If we take the Pithecanthropes who lived 400 thousand years ago and 450 thousand years ago, then the difference between them will also not be so hot.

At this time, people once again went beyond Africa. As for why this happened, there are many hypotheses, including a catastrophic one, attributing a decisive role to the eruption of the Toba volcano in Sumatra. It could destroy the population of Asia, as a result of which it became easier for reasonable people to populate uninhabited territories. But under New Year information about the discovery made in Israel was published. There they found the most ancient person of a completely sapient structure.

Between 50 and 40 thousand years ago, people ended up in Australia, no later than 12.4 thousand years ago they appeared in America (according to the latest data - 20 thousand years ago). This completed the settlement of the planet. About 28,000 years ago, the Neanderthals disappeared, in Asia the Denisovans disappeared even earlier, but both of them made a genetic contribution to us, so that the only purebred Homo sapiens are blacks in Africa.

The only human species that has survived longer than the Neanderthals and Denisovans are the so-called "hobbits" on the island of Floris in East Indonesia. Their ancestors settled there about a million years ago. Over the subsequent time, they were crushed and turned into people about a meter tall with a brain weighing 400 grams, a very strange physique with strange proportions. They disappeared 17 thousand years ago, when there were reasonable people everywhere. But there is evidence of local residents about some furry little men living in the mountains, whom they, however, drove into a cave and burned, so, perhaps, the “hobbits” survived until the 16th century.

Life on Earth appeared billions of years ago, and since then living organisms have become more complex and diverse. There is a lot of evidence that all life on our planet has a common origin. Although the mechanism of evolution is not yet fully understood by scientists, its very fact is beyond doubt. This post is about the path the development of life on Earth went from the simplest forms to humans, as our distant ancestors were many millions of years ago. So, from whom did man come?

The Earth arose 4.6 billion years ago from a cloud of gas and dust that surrounded the Sun. In the initial period of the existence of our planet, the conditions on it were not very comfortable - in the surrounding outer space many more debris flew, which constantly bombarded the Earth. It is believed that 4.5 billion years ago, the Earth collided with another planet, as a result of this collision the Moon was formed. Initially, the Moon was very close to the Earth, but gradually moved away. Due to frequent collisions at this time, the Earth's surface was in a molten state, had a very dense atmosphere, and the surface temperature exceeded 200°C. After some time, the surface hardened, formed Earth's crust, the first continents and oceans appeared. The age of the most ancient explored rocks is 4 billion years.

1) The most ancient ancestor. Archaea.

Life on Earth appeared according to modern ideas, 3.8-4.1 billion years ago (the earliest found traces of bacteria are 3.5 billion years old). How exactly life arose on Earth is still not reliably established. But probably already 3.5 billion years ago, there was a single-celled organism that had all the features inherent in all modern living organisms and was a common ancestor for all of them. From this organism, all its descendants inherited structural features (they all consist of cells surrounded by a membrane), a way to store the genetic code (in double-helixed DNA molecules), a way to store energy (in ATP molecules), etc. From this common ancestor There were three main groups of unicellular organisms that still exist today. First, bacteria and archaea split among themselves, and then eukaryotes evolved from archaea - organisms whose cells have a nucleus.

Archaea have hardly changed over billions of years of evolution, probably the most ancient human ancestors looked about the same

Although archaea gave rise to evolution, many of them have survived to this day almost unchanged. And this is not surprising - since ancient times, archaea have retained the ability to survive in the most extreme conditions - in the absence of oxygen and sunlight, in aggressive - acidic, salty and alkaline environments, at high (some species feel great even in boiling water) and low temperatures, at high pressures, they are also able to feed on a wide variety of organic and inorganic substances. Their distant highly organized descendants cannot boast of this at all.

2) Eukaryotes. Flagella.

For a long time, extreme conditions on the planet hindered the development complex shapes life, and it was undividedly dominated by bacteria and archaea. Approximately 3 billion years ago, cyanobacteria appeared on Earth. They begin to use the process of photosynthesis to absorb carbon from the atmosphere, releasing oxygen in the process. The released oxygen is first spent on the oxidation of rocks and iron in the ocean, and then begins to accumulate in the atmosphere. 2.4 billion years ago there is an "oxygen catastrophe" - a sharp increase in the oxygen content in the Earth's atmosphere. This leads to big changes. For many organisms, oxygen is harmful, and they die out, being replaced by those that, on the contrary, use oxygen for breathing. The composition of the atmosphere and the climate are changing, it is getting much colder due to a drop in greenhouse gases, but an ozone layer appears that protects the Earth from harmful ultraviolet radiation.

About 1.7 billion years ago, eukaryotes evolved from archaea - single-celled organisms whose cells had a more complex structure. Their cells, in particular, contained a nucleus. However, the resulting eukaryotes had more than one predecessor. For example, mitochondria, important building blocks of the cells of all complex living organisms, evolved from free-living bacteria taken over by ancient eukaryotes.

There are many varieties of unicellular eukaryotes. It is believed that all animals, and hence man, descended from unicellular organisms that learned to move with the help of a flagellum located behind the cell. The flagella also help filter water in search of food.

Choanoflagellates under a microscope, according to scientists, it was from such creatures that all animals once originated

Some species of flagellates live by uniting in colonies; it is believed that the first multicellular animals once originated from such colonies of protozoa.

3) Development of multicellular. Bylateria.

Approximately 1.2 billion years ago, the first multicellular organisms appeared. But evolution is still slowly advancing, in addition to the development of life is hindered. So, 850 million years ago, global glaciation begins. The planet has been covered with ice and snow for more than 200 million years.

The exact details of the evolution of multicellular organisms are, unfortunately, unknown. But it is known that after some time the first multicellular animals were divided into groups. Sponges and lamellar sponges that have survived to this day without any special changes do not have separate organs and tissues and filter out nutrients out of the water. Coelenterates are not much more complicated, having only one cavity and a primitive nervous system. All other more developed animals, from worms to mammals, belong to the group of bilateria, and their hallmark is the bilateral symmetry of the body. When the first bilateria appeared is not known for certain, it probably happened shortly after the end of the global glaciation. The formation of bilateral symmetry and the appearance of the first groups of bilateral animals probably took place between 620 and 545 million years ago. Findings of fossil imprints of the first bilaterians date back to 558 million years ago.

Kimberella (imprint, appearance) - one of the first species of bilateria discovered

Shortly after their appearance, bilateria are divided into protostomes and deuterostomes. Almost all invertebrates, worms, mollusks, arthropods, etc., descend from protostomes. The evolution of deuterostomes leads to the appearance of echinoderms (such as sea ​​urchins and stars), hemichordates and chordates (which include humans).

Recently, the remains of creatures called Saccorhytus coronarius. They lived about 540 million years ago. By all indications, this small (only about 1 mm in size) creature was the ancestor of all deuterostomes, and therefore of man.

Saccorhytus coronarius

4) The appearance of chordates. First fish.

540 million years ago, the "Cambrian explosion" occurs - in a very short period of time, a huge number of the most different types sea ​​animals. The fauna of this period has been well studied thanks to the Burgess Shale in Canada, where the remains of a huge number of organisms from this period have been preserved.

Some of the Cambrian period animals found in the Burgess Shale

Many amazing animals were found in the slates, unfortunately long extinct. But one of the most interesting finds was the discovery of the remains of a small animal, called pikaya. This animal is the earliest found representative of the chordate type.

Pikaya (remains, drawing)

Pikaya had gills, a simple intestine and circulatory system, and small tentacles near the mouth. This small animal, about 4 cm in size, resembles modern lancelets.

The appearance of the fish was not long in coming. The first animal found that can be attributed to fish is Haikouichthys. He was even smaller than the pikaya (only 2.5 cm), but he already had eyes and a brain.

This is what haikouichthys looked like

Pikaya and Haikouichthys appeared between 540 and 530 million years ago.

Following them, many larger fish soon appeared in the seas.

The first fossil fish

5) The evolution of fish. Armored and first bony fishes.

The evolution of fish went on for quite a long time, and at first they were not at all the dominant group of living creatures in the seas, as they are today. On the contrary, they had to flee from such large predators like crabscorpions. Fish appeared, in which the head and part of the body were protected by a shell (it is believed that the skull subsequently developed from such a shell).

The first fish were jawless, probably feeding on small organisms and organic debris by drawing in and filtering water. It was only about 430 million years ago that the first fish with jaws appeared - placoderms, or armored fish. Their head and part of their body were covered with a bone shell covered with leather.

ancient armored fish

Some of the armored fish acquired big sizes and began to lead a predatory lifestyle, but next step in evolution was made thanks to the appearance bony fish. Presumably, the common ancestor of the cartilaginous and bony fishes that inhabit the modern seas descended from armored fish, and the armored fish themselves, which appeared at about the same time as the acanthodes, as well as almost all jawless fish, subsequently died out.

Entelognathus primordialis - a likely intermediate form between armored and bony fish, lived 419 million years ago

Guiyu Oneiros, who lived 415 million years ago, is considered the very first of the discovered bony fish, and therefore the ancestor of all land vertebrates, including humans. Compared to predatory armored fish, reaching a length of 10 m, this fish was small - only 33 cm.

Guiyu Oneiros

6) The fish come to land.

While fish continued to evolve in the sea, plants and animals of other classes had already made their way to land (traces of the presence of lichens and arthropods on it were found as early as 480 million years ago). But in the end, fish also took up the development of land. Two classes originated from the first bony fishes - ray-finned and lobe-finned. Most modern fish are ray-finned, and they are perfectly adapted to life in the water. Lobe-finned, on the contrary, have adapted to life in shallow water and in small fresh water bodies, as a result of which their fins have lengthened, and swim bladder gradually turned into primitive lungs. As a result, these fish have learned to breathe air and crawl on land.

Eustenopteron ( ) is one of the fossil lobe-finned fish, which is considered the ancestor of land vertebrates. These fish lived 385 million years ago and reached a length of 1.8 m.

Eusthenopteron (reconstruction)

- another lobe-finned fish, which is considered a likely intermediate form of evolution of fish into amphibians. She could already breathe with her lungs and crawl out onto land.

Panderichthys (reconstruction)

Tiktaalik, the found remains of which date back to 375 million years ago, was even closer to amphibians. He had ribs and lungs, he could turn his head apart from his torso.

Tiktaalik (reconstruction)

One of the first animals, which are no longer classified as fish, but as amphibians, were ichthyostegs. They lived about 365 million years ago. These small animals, about a meter long, although they already had paws instead of fins, could still hardly move on land and led a semi-aquatic lifestyle.

Ichthyostega (reconstruction)

At the time of the emergence of vertebrates on land, another mass extinction occurred - the Devonian. It began about 374 million years ago, and led to the extinction of almost all jawless fish, armored fish, many corals and other groups of living organisms. Nevertheless, the first amphibians survived, although it took them more than one million years to more or less adapt to life on land.

7) The first reptiles. synapsids.

The Carboniferous period, which began about 360 million years ago and lasted 60 million years, was very favorable for amphibians. A significant part of the land was covered with swamps, the climate was warm and humid. Under such conditions, many amphibians continued to live in or near water. But about 340-330 million years ago, some of the amphibians decided to master drier places. They developed stronger limbs, more developed lungs appeared, the skin, on the contrary, became dry so as not to lose moisture. But to really long time to live far from water, another important change was needed, because amphibians, like fish, spawned, and their offspring had to develop into aquatic environment. And about 330 million years ago, the first amniotes appeared, that is, animals capable of laying eggs. The shell of the first eggs was still soft, not hard, however, they could already be laid on land, which means that the offspring could already appear outside the reservoir, bypassing the tadpole stage.

Scientists are still confused about the classification of amphibians of the Carboniferous period, as well as whether to consider some fossil species already early reptiles, or still amphibians, having acquired only some features of reptiles. One way or another, these either the first reptiles, or reptilian amphibians looked something like this:

Vestlotiana is a small animal about 20 cm long, combining the features of reptiles and amphibians. Lived about 338 million years ago.

And then the early reptiles split off, giving rise to three large groups of animals. Paleontologists distinguish these groups according to the structure of the skull - according to the number of holes through which muscles can pass. Figure from top to bottom of the skull anapsis, synapsid and diapsida:

At the same time, anapsids and diapsids are often combined into a group sauropsids. It would seem that the difference is quite insignificant, however, the further evolution of these groups went in completely different ways.

More advanced reptiles evolved from sauropsids, including dinosaurs and then birds. Synapsids also gave rise to a branch of animal-like lizards, and then to mammals.

The Permian period began 300 million years ago. The climate became drier and colder, and early synapsids began to dominate on land - pelycosaurs. One of the pelycosaurs was Dimetrodon, which was up to 4 meters long. He had a large “sail” on his back, which helped to regulate body temperature: to quickly cool down when overheated or, conversely, to warm up quickly by exposing his back to the sun.

It is believed that the huge Dimetrodon is the ancestor of all mammals, and hence man.

8) Cynodonts. The first mammals

In the middle of the Permian period, therapsids descended from pelycosaurs, already more like animals than lizards. Therapsids looked like this:

Typical therapsid of the Permian period

During the Permian period, many species of therapsids, large and small, arose. But 250 million years ago there was a powerful cataclysm. Due to a sharp increase in volcanic activity, the temperature rises, the climate becomes very dry and hot, lava floods large areas of land, and harmful volcanic gases fill the atmosphere. The Great Permian Extinction occurs, the largest mass extinction of species in the history of the Earth, up to 95% of marine and about 70% of land species die out. Of all therapsids, only one group survives - cynodonts.

Cynodonts were mostly small animals, from a few centimeters to 1-2 meters. Among them were both predators and herbivores.

Cynognathus is a species of predatory cynodonts that lived about 240 million years ago. It was about 1.2 meters long, one of the possible ancestors of mammals.

However, after the climate improved, the cynodonts were not destined to capture the planet. Diapsids seized the initiative - dinosaurs evolved from small reptiles, which soon occupied the majority ecological niches. Cynodonts could not compete with them, they were crushed, they had to hide in holes and wait. Revenge was not taken soon.

However, cynodonts survived as best they could and continued to evolve, becoming more and more like mammals:

Evolution of cynodonts

Finally, the first mammals evolved from cynodonts. They were small and were presumably nocturnal. Dangerous existence among a large number of predators contributed to the strong development of all the senses.

Megazostrodon is considered one of the first true mammals.

Megazostrodon lived about 200 million years ago. Its length was only about 10 cm. Megazostrodon fed on insects, worms and other small animals. Probably, he or another similar animal was the ancestor of all modern mammals.

Further evolution - from the first mammals to humans - we will consider in.