A diagramatic representation of the numbers of animals found in an area at ascending trophic levels of a food chain (see illustration). Because only a small proportion of the energy taken in by an organism is converted to tissue and is thus available to consumers at the next trophic level, the number of organisms that can be supported at each level is generally much less than the number at the level that supplies its food (i.e. the level below). See also pyramid of biomass; pyramid of energy.
Pyramid of numbers for a woodland food chain
A diagram of a food chain which shows each trophic level as a horizontal bar, drawn in proportion to the biomass. There is a large fall from producers and primary consumers; thereafter the decreases are smaller. The animals on the higher levels are generally larger and rarer than animals lower down the pyramid. See Kent (2000) PPG 24.
- barter economy
- Barthes, Roland (1915–80)
- Barth, Heinrich (1821–65)
- Barth, Karl (1886–1968)
- Bartholin, Erasmus
- Bartlett, Maurice Stephenson (1910–2002)
- Bartlett, Neil
- Bartlett, Neil (1932–2008)
- Bartlett test
- Bartlett window
- Bartlett–Lewis model
- Bartlett’s identity
- Bartlett’s test for eigenvalues
- Barton, Derek Harold Richard FRS (1918–98)
- Bartonian
- Barton, Sir Derek (1918–98)
- Barton, Sir Derek Harold Richard
- Barton, Sir Edmund (1849–1920)
- Barton–David test
- Baruch, Bernard (1870–1965)
- barycentre
- Barycentric Celestial Reference System
- barycentric coordinates
- Barycentric Coordinate Time
- Barycentric Dynamical Time