Extinction of dinosaurs, mammoths, endangered animals. You must have heard of this subject for sure! But do you know what it means to say that an animal is extinct?
We say that there was a extinction when a particular organism is no longer present in an environment. Extinction can be local or global. We call it a location when it only occurs in a certain region. Global extinction, on the other hand, is one in which the organism is not found throughout the planet. Local extinctions can be reversible, that is, it is possible to reintroduce the species, for example. Global extinctions cannot be reversed.
Extinction is, without a doubt, very important to the process of evolution. Imagine that the extinction of dinosaurs in the Cretaceous Period never occurred. Would mammals have developed in such a way?
Although the Cretaceous extinction is the best known, the largest mass extinction occurred in the Permian. This extinction was so great that it affected marine and terrestrial life, being probably the result of intense volcanism. It is believed that more than 90% of living species during this period were extinct.
When a large amount of species is eliminated, as in the Permian extinction, we call it mass extinction. However, extinctions occur all the time with one species or another. These extinctions are called background extinctions.
The causes of prehistoric extinctions were associated with catastrophic events, such as the fall of meteorites, climate change, volcanism and changes in sea level or even large epidemics. Extinctions in modern times may have the same causes as extinctions in prehistory, however, today we have a factor far more dangerous than any meteor: man.
Man is largely responsible for most of the current extinctions. Man destroys environments, invades the habitats of other animals, hunts, kills and deforests. Without a doubt, it is a big problem for many species.
Currently, several species are at risk of disappearing completely due to anthropic action. A very well-known case is that of the Spix's Macaw, a species that is extinct in the wild, being found only in captivity. Its elimination from the natural environment occurred mainly as a result of animal trafficking and destruction of the caatinga, its habitat.
In addition to the Spix's Macaw, other species are at risk of being eliminated from Earth. Every year, lists are released with species that are at risk of becoming extinct, including the sloth and the manatee.
By Ma. Vanessa dos Santos
Source: Brazil School - https://brasilescola.uol.com.br/o-que-e/biologia/o-que-e-extincao.htm
