APES Unit 2

Genetic diversity

The range of genetic material present in a gene pool or population of a species.

Species diversity

The number and relative abundance of species in a biological community.

Habitat diversity

The range of different habitats or number of ecological niches per unit area in an ecosystem, community or biome.

Species richness

the number of different species in a community

Provisioning services

Benefits of biodiversity that humans use, including lumber, fur, meat, crops, water, and fiber

Regulating services

the service provided by natural systems that helps regulate environmental conditions; indirectly benefits humans

Cultural services

benefits of biodiversity that provide aesthetic, spiritual, or recreational value

Supporting services

the basic ecosystem processes, such as nutrient cycles and soil formation, that are needed to maintain other services

Island biogeography

• proposes that the number of species found on an undisturbed island is determined by immigration and extinction

• Distance from mainland: closer island, higher immigration

• Size of island: small island have fewer species than large islands and smaller target for immigration...higher extinction because less resources and diversity

Specialist species

Species with a narrow ecological niche. They may be able to live in only one type of habitat, tolerate only a narrow range of climatic and other environmental conditions, or use only one type or a few types of food. typically r-selected

Generalist species

Species with a broad ecological niche. They can live in many different places, eat a variety of foods, and tolerate a wide range of environmental conditions. typically K-selected

Ecological tolerance

the range of conditions, such as temperature, salinity, flow rate, and sunlight that an organism can endure before injury or death results

Primary succession

An ecological succession that begins in an area where no biotic community previously existed

Secondary succession

reestablishment of a damaged ecosystem in an area where the soil was left intact

Keystone species

a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically.

Indicator species

Species that serve as early warnings that a community or ecosystem is being degraded.

Pioneer species

First species to populate an area during primary succession

Climax community

A stable, mature community that undergoes little or no change in species over time