Eco Evo Unit 2: Community Ecology

aposematic coloration

coloration that is meant to warn predators away

Batesian mimicry

a harmless species imitates the warning coloration of a harmful one

Mullerian mimicry

multiple species share the same warning coloration, but all of them actually have defenses

Emsleyan/Mertensian mimicry

a deadly prey mimics a less dangerous one

competitive exclusion principle

two species cannot occupy the same niche in a habitat, different species cannot coexist in a community if they are competing for the same resources

symbioses/ symbiotic relationships

close interactions between individuals of different species over an extended period of time which impact the abundance and distribution of the associating populations

commensal relationship

occurs when one species benefits from the close, prolonged interaction, while the other neither benefits nor is harmed

mutualism

both species benefit from the interaction

parasite

an organism that lives in or on another living organism and derives nutrients from it

host

the organism in which the parasite lives

parasitism

the parasite benefits, the host is harmed

foundation species

a species that has the greatest influence on a community’s overall structure

species richness

the number of species living in a habitat or biome

island biogeography

attempts to explain the relatively high species richness found in certain isolated island chains, including the Galapagos Islands

keystone species

a species whose presence is key to maintaining biodiversity within an ecosystem and to upholding an ecological community’s structure

environmental disturbances

examples include volcanoes, earthquakes, storms, fires, and climate change

primary succession

when newly exposed or newly formed land is colonized by living things

secondary succession

when part of an ecosystem is disturbed and remnants of the previous community remain

pioneer species

hearty plants and lichens with few soil requirements, the first species to grow after a primary succession occurs

climax community

final stage of succession, where a stable community is formed by a characteristic assortment of plant and animal species

community

populations of different species (heterospecific) within an area and the interactions among them

fundamental niche

theoretical range of environmental conditions that a species can tolerate

realized niche

portion of the fundamental niche that is actually occupied (given limiting factors)

asymmetric competition

one species outcompetes the other

niche differentiation (resource partitioning)

change in resource use caused by competition over generations

character displacement

evolutionary changes in traits that makes niche differentiation possible

coevolution

when two interacting species reciprocally influence each other’s adaptations over time

aggressive mimicry

when a predator mimics a desirable species

obligate brood parasites

reproduce only by laying eggs in the nests of other species

species abundance (species evenness)

absolute population size of a particular species relative to the population sizes of other species within the community

species diversity

diversity metric that incorporates both richness and evenness

food web

the feeding relationships among organisms in a community

food chain

a single path within a food web

trophic level

the position of an organism in a food chain

species abundance

absolute population size of a particular species relative to the population sizes of other species within the community

species diversity

diversity metric that incorporates both richness and abundance

Facilitation

conditions become favorable after succession

tolerance

no effect after succession

inhibition

hinders environment after succession

Amensalism

neutral- negative

intraspecific competition

competition between members of the same species

interspecific competition

competition between members of different species

Density-dependent regulation

logistic growth

density-independent regulation

exponential growth

Allopatric

separate area

sympatric

same area

Judith Bronstein

ecologist, expert on mutualisms

natural selection should favor cheaters

Nectar robbing

feeding on nectar without pollination