| A | B |
|---|
| climax community | a stable, mature community that undergoes little or no change in species over time |
| limiting factor | any biotic or abiotic factor that restricts the existence, numbers, reproduction, or distribution of organisms |
| primary succession | colonization of new land that is exposed by avalanches, volcanoes, or glaciers by pioneer organisms |
| secondary succession | sequence of community changes that take place after a community is disturbed by natural disasters or human actions |
| succession | orderly, natural changes,and species replacements that take place in ecosystem communities over time |
| aphotic zone | portion of the marine biome that is too deep for sunlight to penetrate |
| biome | group of ecosystems with the same climax communities; biomes on land are terrestrial, biomes in water are aquatic |
| desert | arid with sparse to almost nonexistent plant life; the driest biome |
| estuary | coastal body of water, partially surrounded by land in which fresh water and salt water mix |
| grassland | biome composed of large communities covered with grasses and similar small plants |
| intertidal zone | portion of the shoreline that lies between high tide and low tide lines |
| permafrost | layer of permanently frozen ground that lies underneath the topsoil of the tundra |
| photic zone | portion of the marine biome that is shallow enough for sunlight to penetrate |
| plankton | small organisms that live in the waters of the photic zone; includes both autotrophic and heterotrophic organisms |
| taiga | biome just south of the tundra; characterized by a northern coniferous forest |
| temperate forest | biome composed of forests of broad leaf hardwood trees that loose their leaves annually |
| tropical rain forest | biome near the equator with warm temperatures, wet weather, and lush plant growth |
| tundra | biome that surrounds the north and south poles; treeless land with long summer days and short periods of winter sunlight, beneath the topsoil is a layer of permafrost |
