| A | B |
|---|
| ecology | the study of interactions between organisms and their living and non-living environment |
| abiotic factor | non-living factor that influences an organism |
| biotic factor | living factor that influences an organism |
| ecotone | transition area between ecosystems |
| ecological niche | an organism's role in ecosystem - place in food web, habitat, breeding area, time of day active |
| biome | large geographical area with a specific range of temperatures and precipitation and the organisms adapted to these conditions |
| canopy | upper layer of vegetation in a forest |
| permafrost | permanently frozen soil |
| muskeg | soil above permafrost, swampy or boggy in summer |
| understorey | below the canopy - usually shrubs and smaller trees |
| littoral zone | area from shore of a lake or pond to point where no more plants grow in lake bottom |
| limnetic zone | the area of open lake where there is open water and sufficient light for photosynthesis to occur |
| plankton | autotrophic and heterotrophic organisms found in limnetic zone |
| profundal zone | region beneath limnetic zone in a lake where there is not enough light for photosynthesis |
| litter | upper layer of soil, mainly partially decomposed leaves or grasses |
| topsoil | soil beneath the litter, mainly small particles of rock mixed with humus |
| humus | decaying plant and animal matter |
| subsoil | soil layer beneath topsoil, containing more rock and less organic matter than topsoil |
| bedrock | layer beneath soil, composed of rock |
| groundwater | water in the soil or rock below Earth's surface |
| epilimnion | upper level of a lake that warms up in summer |
| hypolimnion | lower level of lake that remains at low temp. year round |
| thermocline | zone between epilimnion and hypolimnion, in which temp. changes rapidly |
| biotic potential | the maximum number of offspring a species could produce with unlimited resources |
| carrying capacity | the maximum number of individuals in a species that can be supported by an ecosystem |
| law of the minimum | the nutrient in the least supply is the one that limits growth |
| law of tolerance | an organism can survive within a particular range of an abiotic factor |
| density-independent factor | factor in ecosystem that affects members of a population regardless of population density - ex. fire, flood |
| density-dependent factor | factor in ecosystem that affects members of population because of population density - ex. food supply, disease, sunlight |
| slash-and-burn | complete clearing of a forest by felling and burning trees |
| clear-cutting | removal of all trees in an area |
| selective cutting | harvesting of only certain trees in an area |
| oligotrophic | low nutrient levels |
| eutrophic | high nutrient levels |
| prescribed burn | controlled fire set intentionally in designated forest areas |
| coliform bacteria | type of bacteria that occur naturally in intestines of humans and other animals; presence in water indicates the presence of fecal contamination |
| biological oxygen demand (BOD) | amount of dissolved oxygen needed by decomposers to completely break down organic matter in water sample at 20 degrees C over 5 days |
| watershed | land that drains toward a lake or other body of water |
