What two processes sustain the earth’s tremendous biodiversity?

The biodiversity is the variation of the living nature on the Earth. The two main processes that lead to biodiversity are speciation and extinction. Speciation is the formation of new and distinct race or species in the course of evolution, while extinction is the dying out or termination of a race or species, when species no longer reproduce.

Ihaven't done that yet, so no idea,but this is not the right place to ask