ESS SL Glossary

Abiotic Factor

Non-living, physical factor that can influence an organism or ecosystem.

Acute Pollution

Pollution that produces its effects through a short, intense exposure. Symptoms are usually experienced within hours.

Adaptive Radiation

Where an ancestral species evolves to fill different ecological niches, leading to new species.

Albedo

A measure of the reflecting power of a surface in relation to the amount of short-wave radiation received. The amount of light reflected by a surface.

Aquifer

Water-bearing rock.

Bioaccumulation

The build-up of persistent or non-biodegradable pollutants within an organism or trophic level because they cannot be broken down.

Biochemical Oxygen Demand (BOD)

A measure of the amount of dissolved oxygen required to break down the organic material in a given volume of water through aerobic biological activity.

Biodiversity

The amount of biological or living diversity per unit area. It includes the concepts of species diversity, habitat diversity and genetic diversity.

Biomagnification

The increase in concentration of persistent or non-biodegradable pollutants along a food chain.

Biomass

The mass of organic material in organisms or ecosystems (per unit area).

Biome

A collection of ecosystems sharing similar climatic conditions - tundra, tropical, rainforest, desert…

Biosphere

The part of the Earth inhabited by organisms.

Biotic Factor

A living part of an ecosystem that can influence an organism or ecosystem.

Carrying Capacity

The maximum number of a species or “load” that can be sustainably supported by a given environment.

Chronic Pollution

Pollution that produces its effects through low-level, long-term exposure. Disease symptoms develop up to several decades later.

Climax Community

A community of organisms that is more or less stable, and that is in equilibrium with natural environmental conditions such as climate; the end point of ecological succession.

Closed System

A system that exchanges energy but not matter with its surroundings (e.g. Earth)