1. Deserts
1.1. Hot and Dry Desert
1.1.1. warm throughout the year, especially hot in the summer
1.1.2. small nocturnal carnivores: burrowers and kangaroo rats
1.1.3. insects, arachnids, reptiles, and birds
1.2. Semiarid Desert
1.2.1. long and dry summers, low concentrations of rainfall during the winters
1.2.2. rabbits, skunks, lizards, snakes, owls, grasshoppers and ants
1.3. Coastal Desert
1.3.1. moderately cool to warm areas
1.3.2. insects, coyote, badgers, toads, bald eagle, golden eagle, lizards, and snakes
1.4. Cold Desert
1.4.1. cold winters with snowfall and high overall rainfall
1.4.2. jack rabbits, pocket mice, squirrels, badger, and deer only in the winter
2. Grasslands
2.1. Savanna
2.1.1. scattered individual trees
2.1.2. both a dry and a rainy season
2.1.3. zebras, giraffes, kangaroos, elephants, lions
2.2. Temperate Grassland
2.2.1. Steppes
2.2.2. rhinoceroses, wild horses, wolves, prairie dogs, skunks
2.2.3. flat, treeless, covered with grass, have rich soil
3. Tundra
3.1. Arctic
3.1.1. Northern Hemisphere
3.1.2. Cold, desert-like conditions
3.1.3. Polar bears, caribou, snow birds, fish
3.2. Alpine
3.2.1. Located in the mountains where trees cannot grow
3.2.2. mountain goats, sheep, elk
4. Freshwater Regions
4.1. Ponds and Lakes
4.1.1. littoral zone
4.1.1.1. warmest
4.1.1.2. shallow
4.1.1.3. turtles, snakes, ducks
4.1.1.4. species of algae, grazing snails, insects, fishes, and amphibians
4.1.2. limnetic zone
4.1.2.1. plankton
4.1.2.2. well-lighted
4.1.3. profundal zone
4.1.3.1. colder and denser
4.1.3.2. little light
4.2. Streams and Rivers
4.2.1. can be found everywhere
4.2.2. clearer water, has higher oxygen levels, freshwater fish
4.3. Wetlands
4.3.1. areas of standing water that support aquatic plants
4.3.2. marshes, swamps, and bogs
4.3.3. highest species diversity of all ecosystems
4.3.4. many species of amphibians, reptiles, birds, and furbearers
5. Aquatic
5.1. Marine Regions
5.1.1. Oceans
5.1.1.1. largest of all the ecosystems
5.1.1.2. intertidal zone
5.1.1.2.1. where the ocean meets land
5.1.1.2.2. worms, clams, predatory crustaceans, crabs, and shorebirds
5.1.1.3. pelagic zone
5.1.1.3.1. open ocean, generally cold
5.1.1.3.2. surface seaweeds, many species of fish, some mammals such as whales and dolphins
5.1.1.4. benthic zone
5.1.1.4.1. sand, silt, dead organisms
5.1.1.4.2. all sorts of bacteria, fungi, sponges, sea anemones, worms, sea stars, and fishes
5.1.1.5. abyssal zone
5.1.1.5.1. very cold, highly pressured, high in oxygen, low in nutritional content
5.1.1.5.2. many species of invertebrates and fishes
5.1.2. Coral Reefs
5.1.2.1. widely distributed in warm shallow waters
5.1.2.2. barriers along continents
5.1.2.3. corals, microorganisms, invertebrates, fishes, sea urchins, octupuses, and sea stars
5.1.3. Estuaries
5.1.3.1. areas where freshwater streams or rivers merge with the ocean
5.1.3.2. seaweeds, marsh grasses, worms, oysters, crabs, and waterfowl
6. Forest
6.1. Tropical Forests
6.1.1. near the equator, greatest diversity of species
6.1.2. winter is absent, only rainy and dry seasons
6.1.3. birds, bats, small mammals, and insects
6.2. Temperate Forests
6.2.1. eastern north america, northeastern asia, and western and central europe
6.2.2. squirrels, rabits, birds, deer, mountain lion, black bears
6.3. Boreal Forests
6.3.1. eurasia and north america
6.3.2. woodpeckers, moose, bear, fox, wolf, bats, deer