| A | B |
|---|
| Benthic Zone | Bottom of a body of water; inhabited by decomposers, insect larvae, and clams. |
| Biome | Regions that have distinctive climates and organisms and that contain many separate but similar ecosystems. |
| Canopy | In a forest, the covering of tall trees whose intertwinding branches absorb a great amount of sunlight and shade the area beneath. |
| Chaparral | Coastal biome with a Mediterranean climate and low-lying vegetation. |
| Coral Reef | Limestone island in the sea built by coral animals. |
| Desert | Biome that receives less than 10 in. of precipitation a year. |
| Drought-resistance | Characteristic of a plant that allows it to survive in areas of light or sporadic rainfall. |
| Estivating | Practice of lying dormant underground during the summer. |
| Estuary | Aquatic ecosystem in which fresh water from rivers mixes with salt water from the ocean, forming a nutrient trap. |
| Littoral Zone | The shallow-water area near the shores of lakes and ponds where sunlight reaches the bottom. |
| Permafrost | Permanently frozen soil a few inches below the active soil in tundra biomes. |
| Taiga | Biome dominated by conifers and characterized by harsh winters; occurs just below the Arctic Circle; also called northern coniferous forest. |
| Temperate Rain Forest | Cool, humid biome where tree branches are draped with mosses, tree trunks are covered with lichens, and the forest floor is covered with ferns. |
| Temperate Grasslands | Biome occurring in semi-arid interiors of continents; examples are the prairies of North America, the steppes of Russia and Ukraine, and the pampas of South America. |
| Tropical Rain Forest | Warm, wet biome that occurs in a belt around the Earth near the equator and that contains the greatest diversity of organisms on Earth. |
| Savanna | Tropical grassland biome with a short rainy season. |
| Tundra | Biome without trees, where grasses and tough shrubs grow in frozen soil; extends from the Artic Circle to the North Pole. |
| Wetlands | Area of land covered by water for at least part of the year. |
