| A | B |
|---|
| Abiotic factors | Describes nonliving factors in the environment |
| River | Very strong, wide stream – freshwater ecosystem |
| Biome | A large region characterized by a specific type of climate and certain types of plant and animal communities |
| Savanna | A tropical grassland biome with scattered clumps of trees |
| Desert | A hot, dry biome inhabited by organisms adapted to survive high daytime temperatures and long periods without rain |
| Tundra | A far-northern biome characterized by long, cold winters, permafrost, and few trees |
| Permafrost | The permanently frozen ground just below the surface of the soil in the arctic tundra |
| Marine ecosystem | An ecosystem based on salty water |
| Phytoplankton | Microscopic photosynthetic organisms that float near the surface of the ocean |
| Zooplankton | Very small animals that, along with the phytoplankton they consume, form the base of the ocean’s food web |
| Estuary | An area where fresh water from streams and rivers spills into the ocean |
| Tributary | A small stream or river that flows into a larger one |
| Littoral zone | The zone of a lake or pond closest to the edge of the land |
| Open-water zone | The zone of a lake or pond that extends from the littoral zone out across the top of the water and that is only as deep as light can reach through the water |
| Deep-water zone | The zone of a lake or pond below the open-water zone, where no light reaches |
| Wetland | An area of land where the water level is near or above the surface of the ground for most of the year |
| Marsh | A treeless wetland ecosystem where plants such as cattails and rushes grow |
| Swamp | A wetland ecosystem where trees and vines grow |
| Deciduous | Latin word meaning “to fall off”; deciduous trees shed their leaves to save water during winter or the dry season |
| Conifers | Trees that produce seeds in cones and have needle-like leaves |
| Evergreen trees | Trees that stay green all year and do not lose all of their leaves at one time |
| Canopy | Treetops of the rain forest |
| Tropical rain forest | The most biologically diverse place on Earth; nutrients are located in the plants, not in the soil – soil is thin and poor in nutrients |
| Steppes | Grasslands in Russia |
| Prairies | Grasslands in the United States |
| Pampas | Grasslands in Argentina |
| Lichens | A mass of fungal and algal cells that grow together in a symbiotic relationship and that are usually found on rocks or trees |
| Tree line | Also called the timberline – trees cannot grow on mountains above this elevation |
| Climate | The average weather conditions for an area over a long period of time |
| Plankton | Tiny organisms that float near the surface of the water; many are producers; plankton form the base of the ocean’s food chains; two main types – phytoplankton and zooplankton |
| Surface zone | The warm, top layer of ocean water that extends to 300m below sea level; sunlight heats the top 100m; surface currents mix the heated water with the cooler water below |
| Thermocline | A layer of water that extends from 300m below sea level to about 700m below sea level; water temperature in this zone drops with increased depth faster than it does in the other two zones |
| Deep zone | Layer of water extending from 700m to the bottom of the ocean; temperature in this zone averages 2*C |
| Temperature | Temperature of ocean water decreases as the depth of the water increases |
| Intertidal zone | The place where the ocean meets the land; exposed to air for part of the day; sea grasses, periwinkle snails, herons, sea stars, anemones, clams, crabs, and conchs are common |
| Neritic zone | The zone between the Intertidal zone and the Oceanic zone; water becomes deeper and warm and receives lots of sunlight; plankton, seaweeds, sea turtles, and dolphins are common |
| Oceanic zone | Past the Neritic zone; sea floor drops sharply; plankton near surface, fishes, whales, sharks, squids are common |
| Benthic zone | The ocean floor; the deepest parts of the ocean that do not get any sunlight; very cold; fishes, worms, crabs, bacteria |
| Coral reefs | Found in warm, shallow areas of the Neritic zone; Reefs are made up of small animals called corals which live in large groups; when corals die, they leave behind their skeletons; other corals grow on the remains building up layers |
| Sargasso sea | Located in the middle of the Atlantic Ocean; contains floating rafts of algae; where most sea turtles that hatch on the barrier islands of Georgia go to spend their early years |
| Sargassums | Floating rafts of algae |
| Polar ice | Icy waters rich in nutrients and support large numbers of plankton |
| Biotic factors | Describes living (or once-living) factors in the environment |
