Unit 4 stability and change

Micicche's

Clumped Dispersion

Occurs when resources are spread unevenly throughout an ecosystem

Uniform Dispersion

occurs when individuals of the same species must compete for limited resources and territory

Random Dispersion

The least common pattern of dispersion; organisms are found randomly in an ecosystem

A Survivorship curve

a simplified diagram that shows the number of surviving individuals over time from a measured set of births

Type 1 survivorship curve

small number of offspring, live to old age

type 2 survivorship curve

The survivorship curve is roughly equal at all stages of an organism's life

type 3 survivorship curve

Large number of offspring, but many do not live enough to reproduce

exponential growth

(J shaped curve) occurs when a population size increases dramatically over a relatively short amount of time.

logistic growth

(S shaped curve) when a population begins a period of slow growth followed by a period of exponential growth before leveling off to a stable size. This will occur when a population reaches the ecosystem's carrying capacity.

carrying capacity

maximum number of species that a particular environment can support

density dependent

factors that are affected by the number of individuals in an area (competition, predation, parasitism, and disease)

Density independent

factors that can impact a population regardless of the population density (weather, natural disasters, human activity)

Habitat

all of the biotic and abiotic factors in the area where an organism lives

An Ecological niche

contains all the physical, chemical, and biological factors that a species needs to survive and reproduce.

Predation

Is the process by which one organism captures and feeds upon another organism

Competition

occurs when two organisms fight for the same resources

Symbiosis

is a close relationship between two or more organisms of different species that live in direct contact with one another

Mutualism

both organisms benefit from the relationship

Commensalism

one species benefits and the other is neither helped nor harmed

Parasitism

one species benefits and the other is harmed

Biodiversity

is the variety of species within an ecosystem

A Biodiversity Hotspot

an area on earth that is under extreme threat from human action

Endemic Species

A species found in one area on earth and nowhere else. (Lemurs)

Keystone Species

When one species alone has a drastic effect on the entire ecosystem.

primary succession

The establishment of an ecosystem in an area that was previously uninhabited ( volcanic eruption, melting glaciers and landslides)

secondary succession

The establishment of an ecosystem in an area where the soil was left intact