Earth’s BiomesEarth’s Biomes

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Abiotic and biotic factors influence the structure and dynamics of aquatic biomes

Varying combinations of both biotic and abiotic factors Determine the nature of Earth’s many

biomesBiomes

Are the major types of ecological associations that occupy broad geographic regions of land or water

Abiotic and biotic factors influence the structure and dynamics of aquatic biomes

Varying combinations of both biotic and abiotic factors Determine the nature of Earth’s many

biomesBiomes

Are the major types of ecological associations that occupy broad geographic regions of land or water

The examination of biomes will begin with Earth’s aquatic biomes

The examination of biomes will begin with Earth’s aquatic biomes

30N

Tropic of Cancer

Equator

30S

Continentalshelf

Lakes

Coral reefs

Rivers

Oceanic pelagiczone

Estuaries

Intertidal zone

Abyssal zone(below oceanicpelagic zone)

Key

Tropic ofCapricorn

Aquatic biomes Account for the largest part of the

biosphere in terms of area Can contain fresh or salt water

Oceans Cover about 75% of Earth’s surface Have an enormous impact on the

biosphere

Aquatic biomes Account for the largest part of the

biosphere in terms of area Can contain fresh or salt water

Oceans Cover about 75% of Earth’s surface Have an enormous impact on the

biosphere

Many aquatic biomes Are stratified into zones or layers

defined by light penetration, temperature, and depth

Many aquatic biomes Are stratified into zones or layers

defined by light penetration, temperature, and depth

(a)

Littoralzone Limnetic

zone

Photiczone

Benthiczone

Aphoticzone

Pelagiczone

Intertidal zone

Neritic zone Oceanic zone

0

200 m

Continentalshelf

Photic zone

Pelagic zone

Aphoticzone

Benthiczone

2,500–6,000 m

Abyssal zone(deepest regions of ocean floor)

(b)

LakesLakes

Figure 50.17

An oligotrophic lake in Grand Teton, Wyoming

A eutrophic lake in Okavango

delta, Botswana

LAKES

WetlandsWetlands

Figure 50.17

WETLANDS

Okefenokee National Wetland Reserve in Georgia

Streams and riversStreams and rivers

STREAMS AND RIVERS

Figure 50.17A headwater stream in theGreat Smoky Mountains

The Mississippi River farform its headwaters

EstuariesEstuaries

Figure 50.17 An estuary in a low coastal plain of Georgia

ESTUARIES

Intertidal zonesIntertidal zones

Figure 50.17

INTERTIDAL ZONES

Rocky intertidal zone on the Oregon coast

Oceanic pelagic biomeOceanic pelagic biome

Figure 50.17 Open ocean off the island of Hawaii

OCEANIC PELAGIC BIOME

Coral reefsCoral reefs

Figure 50.17 A coral reef in the Red Sea

CORAL REEFS

Marine benthic zoneMarine benthic zone

Figure 50.17 A deep-sea hydrothermal vent community

MARINE BENTHIC ZONE

Climate largely determines the distribution and structure of terrestrial biomes

Climate Is particularly important

in determining why particular terrestrial biomes are found in certain areas

Climate largely determines the distribution and structure of terrestrial biomes

Climate Is particularly important

in determining why particular terrestrial biomes are found in certain areas

Climate and Terrestrial Biomes

Climate and Terrestrial Biomes

Climate has a great impact on the distribution of organisms, as seen on a climograph

Climate has a great impact on the distribution of organisms, as seen on a climograph

Desert Temperate grassland Tropical forest

Temperatebroadleafforest

Coniferousforest

Arctic andalpinetundra

Annual mean precipitation (cm)

Ann

ual m

ean

tem

pera

ture

(ºC

)

100 200 300 400

30

15

0

15

The distribution of major terrestrial biomesThe distribution of major terrestrial biomes

30N

Tropic ofCancer

Equator

Tropic ofCapricorn

30S

Key

Tropical forest

Savanna

Desert

Chaparral

Temperate grassland

Temperate broadleaf forest

Coniferous forest

Tundra

High mountains

Polar ice

Tropical forestTropical forestTROPICAL FOREST

A tropical rain forest in Borneo

Rainfall varies from region to region in these biomes, but is the prime determinant of the

vegetation growing area. These biomes display stratification (layering) in which the

canopy obtains the most sunlight, but very little reaches the ground below.

DesertDesert

Figure 50.20

DESERT

The Sonoran Desert in southern Arizona

This biome is characterized by sparse rainfall (less than 30 cm/year). These ecosystems

are extremely fragile and diverse as plants have developed remarkable abilities to store

water.

SavannaSavanna

Figure 50.20

SAVANNA

A typical savanna in Kenya

This biome is a showcase for large herbivores and their predators. However, the

dominant herbivores are actually insects, especially ants and termites. Grasses and

scattered trees are the dominant vegetation. There is a distinct rainy and dry season, and

the large grazing animals must migrate to greener pastures during the periods of seasonal

drought.

ChaparralChaparralCHAPARRAL

An area of chaparral in California

Figure 50.20Dense, spiny, evergreen shrubs dominate these biomes, which are midlatitude coastal areas with mild, rainy winters and long, hot, dry summers.

Temperate grasslandTemperate grassland

Sheyenne National Grassland in North Dakota

Figure 50.20

TEMPERATE GRASSLAND

Seasonal drought, occasional fires, and grazing by large mammals prevent establishment of woody shrubs and trees. These biomes contain soil that is both deep and rich in nutrients, providing fertile land for agriculture.

Coniferous forestConiferous forest

Rocky Mountain National Park in Colorado

CONIFEROUS FOREST

Cone-bearing trees such as pine, spruce, fir and hemlock dominate these biomes. This

biome is also referred as the taiga, and is the largest terrestrial biome on Earth, receiving

heavy snowfall during the winter. The trees in these forests are being logged at an

alarming rate, and the old-growth stands of these trees may soon disappear.

Temperate broadleaf forestTemperate broadleaf forest

Figure 50.20

TEMPERATE BROADLEAF FOREST

Great Smoky Mountains National Park in North Carolina

Dense stands of deciduous trees are the trademark of these biomes. They occur throughout midlatitudes where there is sufficient moisture to support the growth of large trees. The trees that inhabit these biomes drop their leaves before winter when temperatures are too low for effective photosynthesis.

TundraTundraTUNDRA

Denali National Park, Alaska, in autumnPermafrost, bitterly cold temperatures, and high winds are responsible for the absence of

trees in this extreme biome. Although very little rainfall is received over the course of a

year, water cannot penetrate the underlying permafrost and accumulates in pools on the

shallow topsoil during the short summer. This biome accounts for 20% of Earth’s land

surface.