AP Bio Unit 8 Ch. 54 Vocab

communities

assemblage of populations in area or habitat

ecological niche

an organism’s interaction with the biotic and abiotic resources in the environment/how it “fits into” an ecosystem

competitive exclusion principle

no two species can occupy the same niche

symbiotic interactions

competition, predation, mutualism, commensalism

predator/prey adaptations

predator: locate and subdue prey

prey: defend and elude

anti-predator adaptations

1. hide from predators (camouflage)

2. warn predators that they’re undesirable

aposematic coloration

batesian mimicry and mullerian mimicry

batesian mimicry

palatable or harmless species mimics a harmful model

mullerian mimicry

two or more unrelated dangerous organisms exhibit closely similar warning systems

community structure

species diversity, composition (dominant species) , keystone species, changes over time

species diversity

greater diversity = greater stability

more food resources, more habitats, more resilience in face of enviro change

keystone species

important regulating effect on other species in community

increases diversity in habitat

introduced species

species living outside its native distributional range, humans put them there

10% survive and thrive

effects of introduced species (IMP

competes w/ native species for resources, displaces native species, preys on native species, reduces biodiversity

invasive species

organism not native to an ecosystem and causes harm

not held in check by predators/disease that regulate native species

ecological succession

transition in species composition over time

occurs after a disturbance

primary succession

begins with lifeless area without soil, then bacteria and lichen make soil, then grasses and shrubs move in

secondary succession

existing community cleared, base soil still intact

fires release nutrient formerly locked up in tissues of tree (IMP)

effects of fires on communities

recycle dead plant matter, make nutrients available

food chain structure

producer → primary consumers → secondary consumers → tertiary consumers → detritivores/decomposers

dynamic stability hypothesis

long food chains are less stable than short chains

at higher trophic levels population fluctuation is magnified

10% passed from one level to the next

food chain

transfer of food between trophic levels (level of consumption)

trophic efficiency: % of production transferred from one level to the next

food web

summarizes trophic relationships in a community

more realistic than food chain