| A | B |
|---|
| populations | In an ecosystem, populations change as conditions change |
| El Nino | a climate change in which westward-flowing trade winds in the Pacific Ocean change periodically |
| competition | a situation i which two or more organisms aattempt to use the same resources |
| human activities | can accelerate a change in an ecosystem |
| biomes | large geographic region with a particular kind of climate and community |
| warmest biome | located near the equator |
| tundra | the northermost and coldest biome |
| permafrost | ground that is permanently frozen |
| taiga | forest biome, characterized by conifers |
| temperate deciduouis forest | forest biome, characterized by trees that lose their leaves each year |
| grassland | biome characterized by few trees and many grasses |
| tropical rain forest | has muchnrainfall and high temperatures all year |
| desert | little rainfall and high daytime temperature |
| saltwater biome | water that has a high salt content |
| plankton | microscopic, free floating organisms that serves as food for larger organisms |
| freshwater biome | water biome that has a low salt cotent |
| estuary | place where fresh water from rivers or streams mixes with saltwater from the ocean |
| shallow ocean zone | occurs along the coasts of continents and islands |
| ocean surface zone | sunlight penetrates the top of this zone |
| seep ocean zone | Not much light reaches this zone, very cold temperatures |
