Glossary of Biodiversity Terminology S

The following terms are used by UNEP-WCMC and as such have been defined as UNEP-WCMC interprets them. Whilst we have attempted to include all current thinking on biodiversity terms, there will without a doubt be differences of opinion with respect to definitions.

A-E

F-L

M-R

S| T |U| V| W| X| Y| Z

S	Seedbank	A facility designed for the ex situ conservation of individual plant varieties through seed preservation and storage.
	Selection	Natural selection is the differential contribution of offspring to the next generation by various genetic types belonging to the same populations. Artificial selection is the intentional manipulation by man of the fitness of individuals in a population to produce a desired evolutionary response.
	Species	A group of organisms capable of interbreeding freely with each other but not with members of other species.
	Species diversity	The number and variety of species found in a given area in a region.
	Species richness	The number of species within a specified region or locality.
	Subspecies	A distinct form or race of a species.
	Succession	The more or less predictable changes in the composition of communities following a natural or human disturbance.
	Sustainable development	Development that meets the needs and aspirations of the current generation without compromising the ability to meet those of future generations.
	Sustainable use	The use of components of biological diversity in a way and at a rate that does not lead to the long-term decline of biological diversity, thereby maintaining its potential to meet the needs and aspirations of present and future generations.
	Systematics	The study of the historical evolutionary and genetic relationships among organisms and of their phenotypic similarities and differences.
T	Taxon (pl. taxa)	The named classification unit (eg Homo sapiens, Hominidae, or Mammalia) to which individuals, or sets of species, are assigned. Higher taxa are those above the species level.
	Taxonomy	The classification of animals and plants based upon natural relationships.
	Threatened species	A U.S. technical classification referring to a species that is likely to become endangered within the foreseeable future, throughout all or a significant portion of its range. These species are defined as vulnerable taxa outside the United States by the IUCN.
	Trophic level	Position in the food chain, determined by the number of energy-transfer steps to that level.
V	Variety	See 'Cultivar'.
W	Wild relative	Plant species that are taxonomically related to crop species and serve as potential sources for genes in breeding of new varieties of those crops.
	Wild species	Organisms captive or living in the wild that have not been subject to breeding to alter them from their native state.
	Wildlife	Living, nondomesticated animals.