Populations/Communities/Ecosystem Dynamics

Populations

keystone species: one species that keeps the ecosystem regular

geographic range: the area where a population lives

growth rate: how the population size changes

carrying capacity: the amount of species that an ecosystem can hold based on resources

density: number of individuals in an area

distribution: how they are spaced

  • clumped

  • random

  • uniform

population growth

  • birthrate - deathrate

  • emmigration - immigration

emigration: movement into the population

immigration: movement out of the population

Exponential Growth

  • occurs under ideal conditions

  • j shaped curve on a graph

  • population increases quickly

density-depended causes: limits to growth that depend on the number of individuals in the area

density-independant causes: limits to growth that have no correlation to the number of individuals int the area

Predator- Prey Relationship

  • populations fluctuate

  • prey numbers go up → predators number go up

    • ebb + flow

Measuring Populations

  • mark + recapture

  • random sampling

demography: study of human populations

demographic transition: country has a dramatic change

habitat: the physical area where an animal lives

microhabitats: smaller animals with a larger habitat

microbiome: bacteria that live in soil, water, and our guts

tolerance: the environmental conditions in which an organism can survive

Abiotic Environmental factors: non-living parts of the ecosystem

  • humidity

  • water

  • temperature

  • wind

  • sunlight

Biotic factor: all living organisms and the way they shape their environment

  • producers

  • consumers

  • decomposers

niche: an animal’s habitat, what it eats, how it interacts with other organisms, and the enviorment

competitive exclusion principle: no species can occupy the same niche

resource partitioning: sharing or using different resources as a community

trophic cascade: unintentional interaction

symbiosis: relationship where at lease one species benefits

mutualism: both species benefit

commensalism: one species benefits

parasitism: one species is harmed while the other benifits

Biotic factor: all living organisms and the way they shape their environment