Ecology and Symbiosis: Keystone Species, and Biodiversity

Keystone Predator Species

maintains diversity & ecosystem balance by controlling populations of prey so they don't overpopulate

Keystone Prey Species

Maintain their numbers despite being preyed upon, therefore controlling the # of predators in an area

Competitive Exclusion Principle

Ecological rule that states that no two species can occupy the same exact niche in the same habitat at the same time

Biodiversity

the variety of life in the world or in a particular habitat or ecosystem.

Ecosystem Services

Benefits provided by ecosystems to humans.

Symbiosis

A close relationship between two species that benefits at least one of the species.

Mutualism

both organisms benefit

Commensalism

one organism benefits and the other is unaffected

Parasitism

One organism benefits and the other is harmed

Ecosystem Resilience

an ecosystem's ability to recover from disturbance

Ecosystem Resistance

the ability of an ecosystem to resist change from a disturbance

Keystone Species

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

Niche

(ecology) the role of an organism within its environment and community (affecting its survival as a species)

Exponential Growth (J-Curve)

Population growth that is unhindered because of the abundance of resources for an ever-increasing population.

Logistic Growth

Growth pattern in which a population's growth rate slows or stops following a period of exponential growth

Carrying Capacity

Largest number of individuals of a population that a environment can support

Density-dependent Factors

limiting factor that depends on population size

Density-independent Factors

limiting factor that affects all populations in similar ways, regardless of population size

Predation

An interaction in which one organism kills another for food.

Competition

the struggle between organisms to survive in a habitat with limited resources

Natural Disturbances

all natural events that destroy an ecosystem; fires, hurricanes, tornadoes, droughts, floods

Human-caused Disturbances

deforestation, overgrazing, plowing, water/land/air pollution, overhunting/overfishing, climate change

Ecological Succession

the predictable replacement of one group of species by another group of species over time

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

Population Density

Number of individuals per unit area

Population Distribution

how population is spread out in an area

Immigration

Movement of individuals into a population

Emigration

movement of individuals out of an area