A variety of living organisms and ecosystems they form. Biodiversity has direct value as consumable or useful commodities, indirect value through the provision of ecosystem services, and intrinsic value independent of its utility to humans.

Total mass of living organic matter in a particular area.

A major terrestrial vegetation community, for example, a tropical forest, a temperate grassland or a desert. Similar biomes are found around the world in similar climatic zones, but may have different species of plants and animals.

Interconnected sequence of cause-and-effect relationships within environments, for example, a hydrological (water) cycle; geomorphic processes of weathering, erosion, transportation and deposition; soil-forming processes; land degradation; fluvial processes; and nutrient cycling.

In geography, fresh water in rivers, lakes and dams.