Question: How many species are there?

Hannah Cornish answered on 15 Jan 2019:

Scientist have described and named 1.2-1.5 million species so far. There is a bit of debate about the number because some species have been given a name more than once. When a new species is discovered it has to be described in a scientific journal and given a two part name. Each name is unique and is a bit like a forename and family name. Humans are Homo sapiens, the ‘Homo’ is the genus we belong to which is a gruop of species including our closest relatives like Neanderthals, and the ‘sapiens’ is our species name.

As a rough guide scientists have described around 320,000 plant species, 5,000 mammal species, 10,000 bird species, 34,000 fish species, 5,000 amphibians, 10,000 reptiles and over 1 million insect species.

We think that there are about 5-10 million more species out there that have not been discovered yet. Most of the species that haven’t been described by scientists are invertebrates like insects.