| A | B |
|---|
| ecology | the study of interactions among all organisms and with their physical environment |
| habitat | the place where an organism lives |
| population | all the organisms from the same species living together in the same area |
| community | all of the populations of multiple species interacting in the same area |
| ecosystem | the community of populations along with the abiotic factors (water, etc) in their environment |
| biome | a major regional or global community of organisms |
| resources | living and nonliving components of an environment that support living organisms |
| exponential growth | the number of individuals added each generation increases exponentially |
| logistic growth | when a population begins with exponential growth and then slows as it approaches carrying capacity |
| carrying capacity (K) | the maximum number of individuals of a given species that the community can support (as a population approaches this, environmental resistance will increase--limited resources, predation, disease) |
| density-independent factors | aspects of the environment that limit a population's growth regardless of the density of the population (weather) |
| density-dependent factors | biotic factors that are affected by the density of the population (predation, competition, disease, etc) |
| predation | when one organism (the predator) eats another, the prey |
| ecological niche | role a species plays in a community |
| competitive exclusion principle | no two species can indefinitely occupy the same niche at the same time |
| predator-prey interactions | where the population size of the prey influences the number of predators, and vice versa |
| symbiosis | a close relationship between two different species |
| parasitism | similar to predation where one organism benefits while the other is harmed (host) |
| commensalism | a symbiotic relationship in which one species is benefited and the other is neither benefited or harmed |
| mutualism | a symbiotic relationship in which both members benefit |
| ecological succession | the sequence of biotic changes that regenerate a community or create a community in a previously uninhabited area |
| pioneer species | the first producers to inhabit a community after a disturbance |
| climax community | mature and stable community (old growth forest for example) |
| autotrophs | organisms that require only inorganic nutrients and an outside energy source (sun, sulfur vents) to synthesize organic molecules (producers) |
| heterotrophs | organisms that need preformed organic nutrients that they use as an energy source (consumers) |
| detritivores | organisms that feed on detritus (decomposing parts of organic matter) |
| decomposers | bacteria and fungi--acquire nutrients by breaking down dead organic matter |
| food web | a diagram that describes the trophic (feeding) relationships |
| trophic level | a level of nutrients within a food web or chain (producer, primary consumer, etc) |
| ecological pyramid | the flow of energy with large losses as you go up trophic levels (90% lost) |
| biomass pyramid | a diagram that compares the biomass of different trophic levels within an ecosystem |
| biogeochemical cycles | the pathways by which chemicals circulate through ecosystems involve both living (biotic) and nonliving (abiotic) components |
| greenhouse gases | allow solar radiation to pass through but hinder the escape of infrared rays back into space |
| eutrophication | runoff phosphate and nitrogen from fertilizer use, animal wastes from livestock feedlots, and discharge from sewage treatment plants over enrich the waterways |
| climate change | changes in the Earth's climate due to global warming |
| keystone species | a species that has a large impact on an ecosystem (wolves of yellowstone for example) |
| biomagnification | a pollutant moves up the food chain as predators eat prey, accumulating in higher concentrations in top consumers |
| invasive species | an introduced (non-native) species that was brought to an ecosystem, has no natural predators, and can outcompete native organisms |
| biodiversity | is the variety of living things in an ecosystem |
| limiting factors | environmental factors that oppose growth slow or stop population growth |
