Earth’s Biomes Chapter 23 Section 4

Biome A group of ecosystems with similar climates and organisms. Mostly determined by temperature and precipitation There are 6 major land, or terrestrial, biomes and 2 major water, or aquatic, biomes. Some areas of earth’s surface, such as mountains and the ice caps, do not fall into a major biome.

Grassland Biome Receives between 25 and 75 cm of rain a year. Populated by grasses and non-woody plants. Grasslands in the middle latitudes are called prairies.

Grasslands located close to the equator are called savannas. Savannas can receive as much as 120 cm. of rain a year. Grasslands are home to many large grazing herbivores.

TUNDRA AND DESERT BIOMES

Desert Biomes Receives less than 25 cm. a year Very, very dry because the amount of evaporation is greater than the amount of precipitation. Very hot during the day but much cooler at night Organisms living here are adapted to living in dry, hot conditions.

Tundra Biome Extremely cold and dry Very little precipitation (no more than a desert) Frozen soil is called permafrost Has a short growing season when many mosses, grasses, and shrubs grow.

FOREST BIOMES

Deciduous Forest Biome Trees growing here shed their leaves and grow new ones each year. Receives at least 50 cm. of rain a yr. Temperatures vary throughout the year. Some animals enter a state of hibernation, a low energy state similar to sleep.

Boreal Forest Biome Contains coniferous trees, which produce seeds in cones and have needle-shaped leaves. Very long, cold, snowy winters and much milder summers Also called the taiga. Many animals here are herbivores and eat the seeds produced by the conifers.

Rainforest Biome Two types: tropical rainforest and temperate rain forest. Receives more rain than any biome Very biologically diverse, with a large number of different plants and animals living here.

Tropical rainforest: Found close to the equator Very warm and humid Tall trees form a leafy roof called a canopy. A second level of smaller trees and vines form an understory Temperate Rainforest Found farther north Also receives a lot of rain (300 cm. a year) Much cooler

Aquatic Biomes

Freshwater Biomes Includes ponds, lakes, streams, and rivers Only enough sunlight for photosynthesis near the surface and in shallow water Algae is the most common producer Ponds and lakes are still water while rivers and streams are moving water

Marine Biomes Ocean contains different zones An estuary is where fresh water of a river meets the salt water of the ocean. The part of the shore between the highest high tide and the lowest low tide is called the intertidal zone. The region of shallow water over the continental shelf is called the neritic zone

Surface zone contains algae that carry out photosynthesis The deep zone is completely dark so no photosynthesis can occur. Animals in this zone feed on remains of organisms that sink down from the surface zone.