Chapter 6 Environmental Science

Biodiversity

the total of all genetically based variation in all organisms in the biosphere

Ecosystem diversity

the variety of ecosystems in a given area

Species diversity

the number of different species and their relative abundance in an ecosystem

Genetic diversity

the variety of genes within a species

Ecosystem resilience

the ability of an ecosystem to recover after a disturbance

Ecosystem services

benefits provided by ecosystems to humans

Habitat

an area with specific physical and biological factors that affect which organisms can live there

Microhabitat

a small part of a larger habitat with its own environmental conditions

Tolerance

the range of external conditions within which a species can survive and reproduce

Niche

the role of a species including how it survives and uses resources

Competition

when organisms attempt to use the same limited resources at the same time

Intraspecific competition

competition between members of the same species

Competitive exclusion principle

no two species can occupy the same niche in the same habitat at the same time

Keystone species

a species that has a disproportionately large effect on its ecosystem

Symbiosis

a close relationship between different species

Mutualism

a relationship where both species benefit

Commensalism

a relationship where one species benefits and the other is unaffected

Parasitism

a relationship where one organism benefits and the other is harmed

Ecological succession

predictable changes in a community over time

Primary succession

succession that occurs in areas with no previous life

Secondary succession

succession that occurs after a disturbance that does not destroy the soil

Pioneer species

the first species to colonize a barren area

Climax community

a relatively stable and mature community at the end of succession

Population

A group of individuals of the same species living in the same area

Resource

Any necessity needed for life

Predation

One organism kills and eats another