Normally, the more species in a group, the more fiercely they compete with each other, initially slowing the emergence of new species and eventually leading to their extinction. A new scientific study showed that the situation was somewhat reversed in the genus Homo: The more species formed, the faster new ones appeared. Similar examples are not found among vertebrates, except for insects on isolated islands. Scientists have put forward a number of hypotheses to explain such a surprising result.

For vertebrates (and not only) there are certain patterns of evolution that we know from school. Some basic species of this or that group, filling its entire ecological niche, begin to give rise to new types of specialization. Darwin’s finches, for example, gave rise to new species with the emergence of specialized beaks for smashing solid objects and eating insects.

When all ecological areas accessible to specialist species are occupied, speciation slows down significantly and stops. Then external conditions such as climate, change, number of niches decrease and some species become extinct. This is a standard pattern that is repeated a lot.

In a new study published Nature Ecology and EvolutionAnthropologists from the University of Cambridge (Great Britain) tried to find out whether the same regularities are observed in hominins in general and humans in particular. For this, scientists received 385 reliably dated hominin fossil remains, including Australopithecus, Paranthropus and various species of the genus Homo. They then tried to find out: In hominins, there is a correlation between the rate of emergence of new species and how the rates of emergence of new species and extinction of old ones change thereafter.

The results were unexpected, to say the least. Australopithecus and Paranthropus showed a classic picture: More specialized species could “branch” from less specialized species. At the same time, “experts” experienced serious changes, for example, in teeth and jaws, which allowed the same paranthropes to use new plants that were inedible for them before such changes. However, according to the new study, neither Australopithecus nor Paranthrops reached the limit of species growth before specialization; something stopped them from doing so. Their species decline began before they could fill all available ecological gaps.

This is demonstrated by the fact that the extinction of pioneer species was not observed immediately after the increase in the number of species. Sometimes old and new species coexist in the same area for half a million years. This is impossible if all ecological niches are occupied and there is fierce competition between species in the same group. The same is true for hominins in general.

But as soon as the breed appeared on the arena Homo (2.1 million years ago) the situation changes dramatically. It turns out that the rate of extinction of old species in our genus is inversely proportional to the number of species that reappear. In other words, after the emergence of new species, old species not only disappeared more often, but, on the contrary, disappeared less often than before. It turns out that the competition between these species is strong enough for one to displace the other.

Moreover: The emergence of new species is associated with an increase in the rate of emergence of even more new species. On the face of it, the emergence of “newcomers” seems to have spurred the formation of even newer species.

The authors of the study noted that such an unusual picture has not been known before among vertebrates. The only close examples on land can be found among invertebrates, namely insects, that live on isolated islands in the ocean. Since there were numerous free ecological niches on isolated islands, the emergence of new species did not interfere with old ones. The space for the emergence of new specialized species is therefore very wide and the pressure of new species on old species is minimal.

Researchers have proposed a series of interconnected hypotheses that explain why the evolution of the human species resembles that of insects and not vertebrates. For example, they noted competition between different species of the genus. Homo it may force the migration of some to new geographical areas: for example, the exodus from Africa to Eurasia about two million years ago, the arrival of the Philippines and Flores just under a million years ago, etc.

Also, at least one person Homo erectus, clearly played the role of “ecosystem engineer.” The use of fire, periodic fires and the hunting of megafauna seriously changed the landscapes of first Africa, then Europe and Asia. New ecological niches were opened for other species of the Homo genus in new geographies.

Anthropologists have emphasized that at the end of all this history, this trend was completely reversed: Our species, Homo sapiens, which appeared at least a million years ago, probably replaced the rest; for example, their Ice Age contemporaries, the Denisovans and Neanderthals (perhaps the same fate befell the late Erectus, the human Flores, and the Luson people).

But this happened not because of the extinction of ecological niches, but because of the emergence of the “universal amateur” – a modern person who, although not particularly specialized, managed to survive effectively in a wide range of ecological niches. technologies created.