number of species that live on Earth a new species most diverse and abundant animal groups 250 years species on Earth number of species that live on Earth How Many Species Exist on Earth? Most species url identifying Earth's species tree of life big mammal to go unnoticed the tree of life the tree of life the tree of life tree of life world's undiscovered species of plants and animals url discovered and documented about two million organisms species on Earth how many species exist known diversity of life on the planet Most species cryptic species big mammal to go unnoticed diversity of life on the planet world's undiscovered species of plants and animals Most species Most species the tree of life accurately identifying species biodiversity on our planet tree of life