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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 barren land by pioneer organisms

secondary succession

sequence of changes that take place after a community is disrupted by natural disasters or human actions


orderly, natural changes, and species replacements that take place in communities of an ecosystem over time


the ability of an organism to withstand fluctuations in biotic and abiotic environmental factors

aphotic zone

deep water that never receives sunlight


group of ecosystems with the same climax communities


arid region with sparse to almost nonexistent plant life; the driest biome


coastal body of water, partially surrounded by land, in which freshwater and salt water mix


biome composed of large communities covered with rich soil, grasses, and similar small plants

intertidal zone

portion of the shoreline that lies between high tide and low tide lines

photic zone

portion of the marine biome that is shallow enough for sunlight to penetrate


small organisms that drift and float in the waters of the photic zone; includes both autotrophic and heterotrophic organisms, their eggs and the juvenile stages of many marine animals


biome just south of the tundra; characterized by a boreal or northern coniferous forest composed of larch, fir, hemlock and spruce trees and acidic, mineral-poor topsoils

temperate / deciduous forest

biome composed of forests of broad-leaved hardwood trees that lose their foliage annually

tropical rain forest

biome near the equator with warm temperatures, wet weather, and lush plant growth


biome that surrounds the north and south poles; treeless land with long summer days and short periods of winter sunlight

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