Biodiversity
Biodiversity is the variability among living organisms from terrestrial, marine, freshwater, and other ecosystems, including diversity within species, between species, and of ecosystems. It encompasses genetic differences, the variety and abundance of species, and the ecological communities and interactions that together shape living systems.
In simple terms
Biodiversity operates at several connected levels. Genetic diversity can help populations adapt to changing conditions; species diversity describes the variety of organisms; and ecosystem diversity reflects different habitats and ecological systems. Abundance, distribution, and interactions also matter: a long species list alone does not show whether populations are healthy or ecosystems function well. Biodiversity can therefore be assessed with multiple indicators suited to the place, pressure, and decision being studied.
Why it matters
Food systems, medicines, clean water, soil formation, pollination, climate regulation, cultural identity, and many livelihoods depend on living systems. When biodiversity declines, ecosystems can lose resilience and ecosystem services can weaken. A clear definition also prevents biodiversity from being reduced to a single species count or a generic label for nature.
Example
For example, a wetland assessment might record plant and bird species, genetic variation in a threatened fish population, habitat condition, and connections to nearby rivers. Together these measures reveal more about biodiversity than counting the number of species at one sampling point.
How it differs
Ecosystem
Biodiversity describes variability within and among living systems; an ecosystem is the interacting community of organisms and non-living environment that forms a functional unit.