Communities and Ecosystems



an interaction between species, where one species is destroyed and the other is unaffected

biogeographic realm

large spatial regions where ecosystems share a broadly similar biological evolutionary history


area of study that focuses on the distribution of plants and animals in space or time

climax community

the point in ecological succession when species turnover has reached a steady state


an interaction in which one species benefits but the other neither benefits nor is harmed

continental drift

the movement of Earth's continents over time


an organism that breaks down dead materials and organic wastes


an organism that gets its energy by feeding on dead organic matter

ecological community

a group of species in a specific area

ecological succession

a series of progressive changes in species composition that happen after a disturbance in an ecosystem

facultative mutualist

an organism that can survive on its own but for which there is an added benefit if it remains with another organism

food chain

the relationship between different organisms based on which organism eats or is eaten by another organism

food web

a combination of food chains interacting with each other within an ecosystem


the physical area where an organism lives


an interaction in which both organisms benefit from the relationship


all interactions by a species with the living and nonliving things in an environment

obligate mutualist

an organism that must have its partner in order to survive


a "supercontinent" that existed 335 to 175 million years ago, which later broke apart into the continents


organism that lives in or on another organism and uses its host for its own nutritional needs

pioneer species

species that can colonize an area when no soil is present

primary consumer

an organism that obtains its energy by consuming plant matter

primary succession

the formation of new ecological communities after a disturbance has completely destroyed the ecosystem and left no soil present


an organism that makes its own food, typically by absorbing energy from sunlight

quaternary consumer

an organism at the top of the food chain that obtains its energy by feeding on tertiary consumers

secondary consumer

an organism that obtains it energy by feeding on organism that eat producers

secondary succession

formation of new ecological communities in an area after a disturbance removed most of the organisms but there is soil present afterward


the ecological relationship between two or more organisms that live in direct contact

tertiary consumer

an organism that obtains its energy by feeding on secondary consumers

trophic level

feeding position within a food chain or food web