The experts calculate that between 0.01 and 0.1% of all species will become extinct each year. If the low estimate of the number of species out there is true - i.e. that there are around 2 million different species on our planet - then that means between 200 and 2,000 extinctions occur every year.
What is extinction?
Extinction is the termination of a kind of organism orof a group of kinds (taxon), usually a species.
The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence.
More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out.
It is estimated that there are currently around 8.7 million species of eukaryote globally, and possibly many times more if microorganisms, like bacteria, are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dodos, mammoths, ground sloths, thylacines, trilobites and golden toads.
Through evolution, species arise through the process of speciation—where new varieties of organisms arise and thrive when they are able to find and exploit an ecological nicheand species become extinct when they are no longer able to survive in changing conditions or against superior competition.
The relationship between animals and their ecological niches has been firmly established.
A typical species becomes extinct within 10 million years of its first appearance, although some species, called living fossils, survive with little to no morphological change for hundreds of millions of years.
