The evolutionary process that led to the emergence of modern man is an interesting and at the same time confusing topic. Many of his problems remain open and await their solution. But how many species are represented by humanity in our world, it is known for sure.
The concept of the type of biological
Before directly answering the question of how many species humanity is represented, it is necessary to consider the very concept of species. Under it is supposed a set of individuals that are characterized by the same morphological, physiological, biochemical, environmental, geographical and genetic characteristics. This most complete definition sounds rather complicated, since the concept itself is dynamic. That is, the species changes as a result of evolution through interaction with environmental conditions and with other biological groups.
Only a combined consideration of the above characteristics allows us to judge the existence of a particular species. Among them, genetic features play a fundamental role, since the set of genes (DNA) largely determines the morphology, biochemistry, and a number of innate features of an individual.
When defining the concept under consideration, a different, simplified definition is often given, according to which, if individuals can interbreed and produce prolific offspring, then they make up one species. However, such a definition is incomplete and inaccurate, which will be discussed later.
Modern man
Having become acquainted with the definition of a species, we can go on to answer the question of the article: how many species are represented by humanity, and prove that all people belong to the same species. Such tasks are often posed by the teacher in front of students. The answer to them may be as follows: since all people on the planet have very close DNA to each other, have the ability to think, create works of art, as well as the basic morphological characteristics and ongoing biochemical processes in different races are the same, this means that we are talking about one form that scientists call Homo Sapiens (Homo sapiens).
This answer can be countered by citing the fact that there are people with black and white skin, with big eyes, like Europeans and with narrow ones, like Asians. However, all these minimal morphological differences only confirm the unique ability of Homo Sapiens to adapt to the environment.
So, the black skin of Africans protects them from ultraviolet radiation, and the narrow eyes of Asians are a way of protecting their vision from strong steppe winds and from bright sunlight reflected from snow. Indeed, during the last ice age, most of the Asian continent was covered with ice and snow.
Finally, we give another strong argument that excludes any racist thoughts. Recent studies of the genome of modern humans have found that all existing people come from the same type of women (mitochondrial Eve), who had dark skin color and lived about 200 thousand years ago in the territory of modern Tanzania and from one type of men (chromosomal Adam) who also lived in Africa about 70 thousand years ago.
The development of mankind as a biological species
As mentioned above, modern humanity has gone through a rather complicated, but by evolutionary standards, short time phase of its development.
It was established that our farthest ancestors lived about 45-50 million years ago, however, one of the first hominids that acquired a number of morphological features of modern man are Australopithecus, inhabiting the territory of East Africa 4-2.8 million years ago.
Then, about 2 million years ago, the so-called skilled man appeared - this species is considered the first in the human race. He knew how to make primitive stone tools, which he used for food extraction. Then, 1.8 million years ago, begins the resettlement of man around the world from Africa. This process led to the emergence of a bipedal man. It is believed that he settled most of Asia literally 50 thousand years ago.
Homo sapiens in its modern conception appeared about 200 thousand years ago in Africa. About 70 thousand years ago, he began to migrate from the hottest continent to Eurasia.
When did not only Homo Sapiens exist on Earth?
Literally 30 thousand years ago, the genus of people, according to scientists, was represented by as many as 4 species. Currently, only one of them has survived - a reasonable person. The three other species of humanity were as follows:
- Neanderthals (Europe and the Middle East).
- Denisov's man (South Siberia).
- Homo erectus (most of Asia).
It is well established that the first two of the above species contributed to the gene pool of modern Homo sapiens, in particular, about 2-4% of the genes of Europeans came from Neanderthals, and about the same number of genes in Asia belong to Denisov's man. As for the 3rd species in the list, its role and influence on Homo Sapiens is the subject of modern debate.
Important evolutionary adaptations of man
Knowing how many species humanity is represented (the only modern species of Homo sapiens), let us briefly consider the important evolutionary changes that led to its elevation among other animals:
- walking on two legs, which freed the upper limbs to perform other functions (transporting goods, making tools);
- good vision (a person sees objects in 3 dimensions and in a wide range of colors);
- development of the brain, in particular its frontal lobes.
The last of these changes contributed to the emergence of abstract thinking, a complex language of communication and the emergence of consciousness.
The closest living relatives
Man is the only living species of his kind, but which of the living beings is his closest relative in evolutionary development? Of course, these are chimpanzees with whom we had a common ancestor, who lived about 5-7 million years ago.
To demonstrate how slowly evolution proceeds and strong differences between species appear with a slight change in genes, we give the following figure: our DNA differs from that for chimpanzees by only 1.24%.