| A | B |
|---|
| limiting factor | any biotic or abiotic factor that restricts the existence, numbers, reproduction or distribution of organisms |
| succession | changes in an ecosystem that take place as populations grow and decrease in size or move in and out of the area |
| primary succession | colonization of new sites by communities or organisms |
| climax community | a stable, mature community that undergoes little or no succession |
| secondary succession | a sequence of community changes that takes place when a community is disrupted by natural disasters or human actions |
| biome | a large group of ecosystems that share the same type of climax community |
| photic zone | the portion of the marine biome that is shallow enough for sunlight to penetrate |
| aphotic zone | deeper water that never receives sunlight |
| photic | light |
| aphotic | without light |
| estuary | a costal body of water, partially surrounded by land, in which fresh water and salt water mix |
| intertidal zone | the portion of shoreline that lies between high and low tide lines |
| plankton | microscopic organisms that float in the waters of the photic zone |
| tundra | a treeless land with long summer days and short periods of winter sunlight |
| permafrost | a layer of permanently frozen ground that is below the topsoil |
| taiga | the northern coniferous forest |
| desert | an arid region with sparse to almost nonexistent plant life |
| grasslands | large communities covered with grasses and similar small plants |
| temperate forest | forest dominated by broad-leaved hard wood trees that lose their foliage annually |
| tropical rain forest | a region of uniformly warm, wet weather dominated by lush plant growth |
