| A | B |
|---|
| ecology | scientific study of the interactions among organisms and between organisms and their environment |
| biotic factor | any living part of an environment |
| abiotic factor | nonliving physical or chemical condition in an environment |
| population | group of individuals of the same species living in a particular area at the same time |
| community | ll the organisms living in an area |
| ecosystem | community of living things plus the nonliving features of the environment that support them |
| biosphere | all the parts of the planet that are inhabited by living things; sum of all Earth's ecosystems |
| habitat | an organism's specific environment, with characteristic abiotic and biotic factors |
| tropics | regions between 23.5° N latitude and 23.5° S latitude; warmest temperature zones on Earth |
| microclimate | climate in a specific area that varies from the surrounding climate region |
| polar zones | the regions north of the Arctic Circle (66.5° N) and south of the Antarctic Circle (66.5° S), that receive the smallest amount of direct sunlight year-round |
| temperate zones | latitudes between the tropics and polar regions in each hemisphere |
| current | riverlike flow pattern within a body of water |
| biome | major type of terrestrial ecosystem that covers a large region of Earth |
| chaparral | temperate coastal biome dominated by dense evergreen shrub |
| tropical rain forest | type of forest near the equator that receives as much as 250 cm of rainfall yearly |
| savanna | grassland with scattered trees; found in tropical regions of Africa, Australia, and South America |
| desert | land area that receives less than 30 centimeters of rain per year |
| temperate grassland | biome characterized by deep, nutrient-rich soil that supports many grass species |
| permafrost | permanently frozen subsoil |
| temperate deciduous forest | forest in a temperate region, characterized by trees that drop their leaves annually |
| coniferous forest | forest populated by cone-bearing evergreen trees; mostly found in northern latitudes |
| tundra | biome in the Arctic Circle or on high mountaintops, characterized by bitterly cold temperatures and high winds |
| photic zone | regions of a body of water where light penetrates, enabling photosynthesis |
| hydrothermal vent | opening in the ocean floor where hot gases and minerals escape from Earth's interior |
| phytoplankton | microscopic algae and cyanobacteria that carry out photosynthesis |
| aphotic zone | deep areas of a body of water where light levels are too low to support photosynthesis |
| benthic zone | bottom of an aquatic ecosystem; consists of sand and sediment and supports its own community of organisms |
| estuary | area where fresh water from streams and rivers merges with salty ocean water; productive ecosystem |
| pelagic zone | open water above the ocean floor |
| intertidal zone | area of shore between the high-tide and low-tide lines |
| neritic zone | area of ocean that extends from the low-tide line out to the edge of the continental shelf |
| oceanic zone | vast open ocean from the edge of the continental shelf outward |
| zooplankton | microscopic animals that swim or drift near the surface of aquatic environments |
