All life on the planet is striking in its diversity. Since the earliest times, mankind has studied, tried to organize and count the number of species on the planet. But even today, despite the relatively high degree of development of biology, not a single scientist can answer exactly the question of how many animal species on Earth coexist near us.
General concepts
Under the guise of biology, we understand a group of living organisms that are similar by some criteria and capable of interbreeding with the birth of prolific offspring.
There are plenty of species criteria:
- morphological (external and internal structure);
- genetic (genome structure);
- biochemical (similarity of metabolic processes);
- physiological (similarity of vital processes);
- geographical (habitat);
- ecological (a place in the ecological niche).
You can expand this list. To determine the type and make it into the classification system, a rather painstaking analysis is necessary.
Animals and plants
Oddly enough, but even in determining the belonging of an organism to a particular taxon it can cause difficulties. Today, biologists are inclined to believe that animals are organisms that use ready-made organic substances for life and are unable to synthesize them from inorganic ones. Plants themselves synthesize organic matter for their vital processes. Again, this is very simplistic.
Evolutionary difficulties
Calculating how many species of animals and plants on Earth exist at a given time is quite problematic given the evolution of every second. Each species once appears, is experiencing flowering or decline, disappears or evolves.
Some biologists cite the data that every hour on the planet three species of living organisms permanently disappear, respectively, about 72 species will disappear in a day. How many species arise can be judged by the fact that every year the classification and systematics is replenished with thousands of new described species. It is significant that almost every catch with the help of deep-sea trawls of research vessels brings to oceanologists representatives of species not previously described.
Paleontology data
How many animal species are there on earth? According to the calculations of paleontologists, this is 2-3% of the total number that have appeared on the planet since the inception of life. Extinction is a normal process for evolution, the same as the emergence of new species. Therefore, the answer to the question, how many species of animals are left on Earth, requires a determination of the time frame. Nobody has canceled natural selection in the struggle for existence.
For example, there is evidence that from 1600 to 1969, 38 species of the class of mammals and 94 species of the class of birds disappeared from the face of the earth.
Disappeared or not?
There is such an international species conservation commission (IUCN), according to which 801 species of animals officially described have disappeared from the face of the Earth over the past 500 years. Sometimes a species declared extinct reappears.
In the 20s of the previous century, this happened to the northern elephant seal. The species was declared extinct as a result of ruthless extermination by man. However, a lost group of elephants on the outskirts of Mexico, on the small island of Guadalupe, managed to survive, and by a miracle of about 100 individuals this species of large mammals was able to regain its population. Today, the species is not threatened with extinction.
Is extinction really scary
Even the children know how the disappearance of a butterfly alone can affect the evolution of life on the planet. Everyone watched the eponymous Hollywood blockbuster. The plot of the film has a very real background. Biologists give an example of how a change in one species in the ecosystem of the Amazon floodplain leads to enormous consequences. Up to terrain changes. So the life of one little butterfly in nature, where everything is connected by the thinnest threads-bonds, is as important as the existence of all mankind.
And yet, how many animal species are there on Earth?
Be that as it may, attempts are being made to determine the number of species. Recent scientific work by universities in Canada and Hawaii gives a figure of 8.7 million - that's how many species of animals on Earth exist today. Moreover, 80% of this figure are species not yet described by modern science. There are no fewer questions from non-specialists on this subject than from professional taxonomists.
Other data indicate the existence of 150 million species, of which only 1.5 million have been studied.
Why count?
The knowledge of how many animal species on Earth, according to biologists, is not only of theoretical interest. The practical significance of such knowledge will allow ecologists to calculate at what losses there will come a point of no return, a point of ecological disaster on a planetary scale. Such calculations have their own methods and can help develop ways to maintain stable ecosystems that determine the existence of life on the planet.
The world will never know the exact data on the amount of species diversity . This is the prognosis of biologists. We will always guess for plus, minus a million. However, this does not give rise to humanity to abandon anxiety. The fragility of the planet’s ecosystem, the significance of every, even a tiny organism in the biosphere, is the greatest value presented by nature.