BIOL 1442 Ch 45 Community Ecology

species diversity

the number of species occupying the same habitat and their relative abundance

Ecology is studied at the community level to

understand how species interact with each other and compete for the same resources

Mechanical defenses

discourage animal predation and herbivory by causing physical pain to the predator or by physically preventing the predator from being able to eat the prey

Chemical defenses are produced by

animals and plants

camouflage

avoiding detection by blending in with the background

aposematic coloration

species using coloration as a way of warning predators that they are not good to eat

Batesian mimicry

harmless species imitates the warning coloration of a harmful one

Müllerian 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

resource partitioning

minimizes direct competition

Symbiotic relationships are

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

two species benefit from their interaction

parasite

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

a parasite is ( ) to kill the host

unlikely

Foundation species

“base” or “bedrock” of a community, having the greatest influence on its overall structure

Biodiversity

communities biological complexity based on species richness and relative abundance

species richness

used to describe the number of species living in a habitat or biome

A determining factor of species richness includes

latitude

Greatest species richness occurs at the

equator

Lowest species richness occurs near the

poles

the study of island biogeography attempts to explain the

relatively high species richness found in certain isolated island chains

Relative species abundance

the number of individuals in a species relative to the total number of individuals in all species within a habitat, ecosystem, or biome

keystone species

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

Community dynamics

changes in the community structure and composition over time that can be induced by environmental disturbances

environmental disturbances

volcanoes, earthquakes, storms, fires, and climate change

primary succession

newly exposed or newly formed land is colonized by living things

secondary succession

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

pioneer species

hearty plants and lichens with few soil requirements

climax community

equilibrium state which will remain stable until the next disturbance