IUCN is an International Union for Conservation of Nature, and It assesses the biological species in the world which are at risk of extinction. IUCN mainly aims to focus on the preservation of the world’s species to decrease species extinction. IUCN mainly focuses on the Extinct, Extinct in the wild, Critically endangered, Endangered, Vulnerable, Near threatened, The Least concern, Data deficient type species.

Species is defined as a group of closely related individuals that are capable of interbreeding among themselves and producing fertile offsprings but are reproductively isolated from individuals of the other species. It is the basic taxonomical unit, ranking below a genus. Homo sapiens (humans), Felis catus (domestic cats), and Vulpes vulpes (red fox) are some examples of species.