Earth’s BiomesEarth’s Biomes

Chapter 23Chapter 23

Section 4Section 4

BiomeBiome A group of ecosystems with similar A group of ecosystems with similar

climates and organisms.climates and organisms. Mostly determined by temperature Mostly determined by temperature

and precipitationand precipitation There are 6 major land, or terrestrial, There are 6 major land, or terrestrial,

biomes and 2 major water, or biomes and 2 major water, or aquatic, biomes.aquatic, biomes.

Some areas of earth’s surface, such Some areas of earth’s surface, such as mountains and the ice caps, do as mountains and the ice caps, do not fall into a major biome.not fall into a major biome.

Grassland BiomeGrassland Biome

Receives between 25 and 75 cm of Receives between 25 and 75 cm of rain a year. rain a year.

Populated by grasses and non-woody Populated by grasses and non-woody plants.plants.

Grasslands in the middle latitudes Grasslands in the middle latitudes are called prairies.are called prairies.

Grasslands located close to the Grasslands located close to the equator are called savannas.equator are called savannas.

Savannas can receive as much Savannas can receive as much as 120 cm. of rain a year.as 120 cm. of rain a year.

Grasslands are home to many large Grasslands are home to many large grazing herbivores.grazing herbivores.

TUNDRA AND DESERT BIOMESTUNDRA AND DESERT BIOMES

Desert BiomesDesert Biomes

Receives less than 25 cm. a yearReceives less than 25 cm. a year Very, very dry because the amount Very, very dry because the amount

of evaporation is greater than the of evaporation is greater than the amount of precipitation.amount of precipitation.

Very hot during the day but much Very hot during the day but much cooler at nightcooler at night

Organisms living here are adapted to Organisms living here are adapted to living in dry, hot conditions.living in dry, hot conditions.

Tundra BiomeTundra Biome

Extremely cold and dryExtremely cold and dry Very little precipitation (no more Very little precipitation (no more

than a desert)than a desert) Frozen soil is called permafrostFrozen soil is called permafrost Has a short growing season Has a short growing season

when many mosses, grasses, and when many mosses, grasses, and shrubs grow.shrubs grow.

FOREST BIOMESFOREST BIOMES

Deciduous Forest Deciduous Forest BiomeBiome

Trees growing here shed their leaves Trees growing here shed their leaves and grow new ones and grow new ones

each year.each year. Receives at least 50 cm. of rain a yr.Receives at least 50 cm. of rain a yr. Temperatures vary throughout the Temperatures vary throughout the

year.year. Some animals enter a state of Some animals enter a state of

hibernation, a low energy state hibernation, a low energy state similar to sleep.similar to sleep.

Boreal Forest BiomeBoreal Forest Biome

Contains coniferous trees, Contains coniferous trees, which produce seeds in cones which produce seeds in cones

and have needle-shaped leaves.and have needle-shaped leaves. Very long, cold, snowy winters and Very long, cold, snowy winters and

much milder summersmuch milder summers Also called the taiga.Also called the taiga. Many animals here are herbivores Many animals here are herbivores

and eat the seeds produced by the and eat the seeds produced by the conifers.conifers.

Rainforest BiomeRainforest Biome

Two types: tropical rainforest and Two types: tropical rainforest and temperate rain forest.temperate rain forest.

Receives more rain than any biomeReceives more rain than any biome Very biologically diverse, with a large Very biologically diverse, with a large

number of different plants and number of different plants and animals living here.animals living here.

Tropical rainforest:Tropical rainforest:– Found close to the equatorFound close to the equator– Very warm and humidVery warm and humid– Tall trees form a leafy roof Tall trees form a leafy roof

called a canopy.called a canopy.– A second level of smaller A second level of smaller

trees and vines form an trees and vines form an understoryunderstory

Temperate RainforestTemperate Rainforest– Found farther northFound farther north– Also receives a lot of rain Also receives a lot of rain

(300 cm. a year)(300 cm. a year)– Much cooler Much cooler

Aquatic BiomesAquatic Biomes

Freshwater BiomesFreshwater Biomes

Includes ponds, lakes, streams, and Includes ponds, lakes, streams, and riversrivers

Only enough sunlight for Only enough sunlight for photosynthesis near the surface and photosynthesis near the surface and in shallow waterin shallow water

Algae is the most common producerAlgae is the most common producer

Ponds and lakes are still water while Ponds and lakes are still water while rivers and streams are moving waterrivers and streams are moving water

Marine BiomesMarine Biomes Ocean contains different Ocean contains different

zoneszones An estuary is where fresh An estuary is where fresh

water of a river meets the water of a river meets the salt water of the ocean.salt water of the ocean.

The part of the shore The part of the shore between the highest high tide between the highest high tide and the lowest low tide is and the lowest low tide is called the intertidal zone.called the intertidal zone.

The region of shallow water The region of shallow water over the continental shelf is over the continental shelf is called the neritic zonecalled the neritic zone

Surface zone contains algae that Surface zone contains algae that carry out photosynthesiscarry out photosynthesis

The deep zone is completely dark so The deep zone is completely dark so no photosynthesis can occur.no photosynthesis can occur.– Animals in this zone feed on remains of Animals in this zone feed on remains of

organisms that sink down from the organisms that sink down from the surface zone.surface zone.