Communities and ecosystems

Microhabitat

tiny part of much larger habitat

• has own set of environmental conditions called microclimate

Microbiome

microbial community

Tolerance

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

Niche

• includes range of physical and biological conditions where a species can survive and reproduce, as well as way it obtains needed resources
• organism’s role within ecosystem too

Competition

when organisms use same limited resources in same place at same time

Intraspecific competition

competition between members of same species

Interspecific competition

competition between different species

Competitive exclusion principle

no two species can occupy exactly same niche is exactly same habitat at exactly same time

Keystone species

species that plays vital and unique role in maintaining structure, stability, and diversity in ecosystem

Symbiosis

relationship between species where a/both species benefits

Commensalism

relationship where one organism benefits and other isn’t helped or harmed

Mutualism

relationship where both species benefit

Parasitism

relationship where one species lives inside or on other species and harms it

Succession

• gradual replacement of one plant community by another through natural processes over time
• usually happens after a disturbance damages or removes existing plants
• at first only small plants grow because soil thin, as time goes on plant roots break down rock and dead plants, creating soil
  • once soil thicker, taller plants able to replace smaller ones

Primary succession

succession starting in area with no existing plant community and no soil

Secondary succession

succession occurring when a disturbance affected existing community but not totally destroyed it

• soil still present

Pioneer species

first species to colonize area during succession

• for primary succession, typically lichen or morse
• for secondary succession, typically small weeds

Climax community

community formed at “end” of succession

• has large, mature plants
• very diverse
• patches of climax communities might be in different stages of secondary succession after natural disturbances because of multiple disturbances

Climate

average weather conditions over long periods of time

• mostly dependent on how much sun area gets overall

Greenhouse effect

some of heat from sun prevented from leaving by gases in atmosphere

• without greenhouse effect, temps would drop below freezing every night