Extinction of species on earth

How many species of living things exist on earth? Understand as a species types of living things with similar phenotypic and genotypic characteristics. In taxonomy, the species (Latin species) is the basic unit of biological classification. It refers to a mental conception applied to a group of living beings. In 1735, the Swedish botanist Carl Linnaeus publishes the first version of his Systema Naturae. Linnaeus had proposed to classify all living things to facilitate their study. For this, he proposed a binominal system, that is to say with two names, that of the kind and that of the species. Linnaeus has named more than 7,000 species in his lifetime and his system has been adopted as Systema Naturae quickly, and we still use it. For example, the human being is Homo sapiens. Of course, the scientist believed that there were no more than 10,000 species of living things in the world. Edward O. Wilson, Editor-in-Chief Frances M. Peter, Associate Editor National Academy of Sciences Smithsonian Institute Washington, DC 1988, reaches more approximate information indicating that there are 8,750,000 (± 1.3 million), number of eukaryotic species (fungi, animals and plants) and prokaryotes (bacteria) that exist on the planet; of which 2 200 are marine. Of the estimated total amount, only 14% have been identified, or 1,224,360. 86% of the planet's species need to be discovered and described, it's like NN. 91% of marine species have not yet been discovered. Up to now, the following proportions have been described: Animals: 7.77 million (12% described); Mushrooms: 611,000 (7% described); Plants: 298,000 (70% described); Protozoa: 36,400 (22% described); Algae and molds: 27,500 (50% described). From Linnaeus (1,735), we have been trying for 250 years to answer the question of how many species exist; and our ignorance was and is such that we thought the figure could be between 3 and 100 million. In 250 years, 1 to 244,360 species have been identified; now, identifying the 8,750,000 of the remaining species would take scientists over 1700 years.

The extinction of species on Earth has not occurred in recent years. But, this happens all the time, as at the end of the Ordovician, there are 438 million years, or 25% of missing families. Devonian, there are 360 ​​million years, or 19% of missing families. Permiano, 245 million years ago, 54% of families and 90% of species disappeared. Trias, there are 205 million years, or 23% of missing families. Cretaceous, 65 million years ago, that 70% of species disappeared. A species is considered endangered, whether it is plant or animal, when all living members of that species are at risk of extinction. "In the 2009 version of the IUCN Red List, there are 2448 animal taxa of the" Endangered "category and 2280 of plants, to which is attached the category" Critically Endangered ". those with 1665 animal taxa and 1575. The "endangered" and "critically endangered" categories contain all species that have shown significant fluctuations in their geographical distribution. with a decrease or fragmentation of it, a population of mature individuals less than 250 or 2500 specimens with a 50% or 20% extinction probability in their wild form, and a sharp decrease in their general population in the last 10 years or three generations, so 70% and 80% respectively "(en.wikipedia.org)

This extinction process is also anthropogenic, due to human participation. It was done in two phases: PHASE ONE, 100,000 years ago, when the first modern humans Homo sapiens began to spread in different parts of the world from Africa. PHASE TWO, 10,000 years ago, when men began to cultivate. The extinction rate of species has accelerated dramatically, due to forest concessions.

Extinction and speciation are two complementary natural processes that have occurred simultaneously since life appeared on Earth. While on the one hand species disappear, on the other hand others appear, although apparently in apparent disproportion, because living things can not develop under abiotic conditions and extreme weather conditions. 50% of the world's biodiversity is found in only 7% of the tropical forest area. Only 8% of these forests are protected. The tropical band, around the equatorial line, is the ecological environment that has more diversity and abundance of species. If anthropogenic activities continue with the limited forms of management of the remaining ecosystems, not only will massive extinctions of species occur, but human living conditions will also be the most inadequate which will actually limit their population.