What Is Biodiversity?

Some of the biodiversity of a coral reef.

Biological diversity — or biodiversity — is a term we use to describe the variety of life on Earth. It refers to the wide variety of ecosystems and living organisms: animals, plants, their habitats and their genes.

Biodiversity can be measured on several different levels:

• Genetic — variation between individuals of the same species.
• Species — species diversity is the variety of species in a given region or area.
• Ecosystem — communities of plants and animals, together with the physical characteristics of their environment (e.g. geology, soil and climate) interlink together as an ecological system, or 'ecosystem'.

Biodiversity is not consistent across the Earth. It is consistently rich in the tropics and in specific regions such as the Cape Floristic Province; it is less rich in polar regions where conditions support much less biomass.

Rapid environmental changes typically cause extinctions; 99.9percent of species that have existed on Earth are now extinct.