Definition and scope of biodiversity

Summary

Biodiversity is the variability of life on Earth. It is commonly defined as the totality of genes, species, and ecosystems in a region, and it can be measured at multiple levels, including genetic variability, species diversity (often linked to species richness), ecosystem diversity, and phylogenetic diversity. Although biodiversity is widely used to replace more specific terms like species diversity and species richness, there is no single fixed definition; different organizations emphasize broad aspects of variability among living organisms and the ecosystems they belong to. The scope of biodiversity extends beyond counting species. It includes how diversity is distributed across the planet (it is generally higher in the tropics and varies with factors such as temperature, precipitation, altitude, soils, and geography), and it also covers how biodiversity changes over time, including major historical mass extinctions and more recent ongoing losses driven largely by human activity. Biodiversity is therefore treated as a multi-scale concept—spanning genes to ecosystems—and it is studied through related fields such as biogeography, which examines spatial patterns of organisms, species, and ecosystems.

Key Points

• 1

  Biodiversity refers to the variability of life and is assessed across multiple levels such as genes, species, ecosystems, and evolutionary relationships.

• 2

  There is no single universally fixed definition; major institutions frame biodiversity as variability among living organisms (within/between species) and the ecosystems they form.

• 3

  Biodiversity is unevenly distributed across Earth, typically higher in the tropics, and varies with environmental and geographic factors.

• 4

  The scope includes both spatial patterns and temporal change, from past mass extinctions to current human-driven biodiversity loss.