1	Ecology
2	The study of the interactions that take place among organisms and their environment
3	Biosphere The part of Earth that supports life Top portion of Earth's crust All the waters that cover Earth's surface Atmosphere that surrounds Earth.
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5	Ecosystem All the organisms living in an area and the nonliving features of their environment
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7	Population All the organisms in an ecosystem that belong to the same species
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9	Community All the populations in an ecosystem
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11	Habitat The place in which an organism lives provides the kinds of food and shelter, the temperature, and the amount of moisture the organism needs to survive
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13	Competition Food Space
14	Competition Competition caused by population growth affects many organisms, including humans Limits population size
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16	Limiting Factor Anything that restricts the number of individuals in a population. Includes living and nonliving features of the ecosystem
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18	Succession Natural, gradual changes in the types of species that live in an area; can be primary or secondary. Primary – begins in a place without soil Secondary – where soil already exists
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21	Primary Succession
22	Secondary Succession
23	Pioneer species A group of organisms, such as lichens, found in the primary stage of succession and that begin an area's soil-building process
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25	Climax community A community that has reached a stable stage of ecological succession
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27	Biome Large geographic areas with similar climates and ecosystems
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29	Includes Tundra Taiga Desert Temperate deciduous forest Temperate rain forest Tropical rain forest, and grassland