# Portal:Extinction

## Introduction

In biology, extinction is the termination of an organism or of a group of organisms (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 percent of all species, amounting to over five billion species, that ever lived on Earth are estimated to have died out. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. In 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described.

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## In the news

20 February 2019 –
One surviving female specimen of the Fernandina Galápagos tortoise species, which was thought to be extinct for more than 100 years, is found. (USA Today)

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