How many species have gone extinct ? 941 species are listed in IUCN Redlist!

A. It depends on the definition of species. If you count only described (known) species, 941 species among evaluated 43700 taxa are listed as extinct or extinct in the wild in IUCN Redlist database. (see PNG for a method to get this number from IUCN's Red List website ). Note that extinct species recorded in 2002 does not mean the species went extinct in 2002 but is decided as extinct in 2002. In addition, there are many undescribed species (see Monitoring and biodiversity indices). Therefore the number of extinct species may be bigger if we include undescribed species. It is noted that the number of extinct species /day is >1, probably ca.10 or more (e.g. WWF website). However, if the extinction rate is not significantly different between described and undescribed species, this is definitely far overestimation.