Essentials of Ecology

142 CHAPTER 7 Climate and Terrestrial Biodiversity

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North

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Equatorialcountercurrent

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Westwindd

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Alaska

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South equatorial current

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Antarctic

Circle

Tropic of

Cancer

Tropic of

Capricorn

Polar (ice) Subarctic (snow) Cool temperate

Warm temperate Dry Tropical

Highland

Major upwelling zones

Warm ocean current

Arctic

Circle

Cold ocean current

River

Active Figure 7-2 Natural capital: generalized map of the earth’s current climate zones, show-

ing the major contributing ocean currents and drifts and upwelling areas (where currents bring nutrients from the

ocean bottom to the surface). Winds play an important role in distributing heat and moisture in the atmosphere,

which leads to such climate zones. Winds also cause currents that help distribute heat throughout the world’s

oceans. See an animation based on this figure at CengageNOW™. Question: Based on this map what is the gen-

eral type of climate where you live?

60 °N

60 °S

30 °N

30 °S

0 °

Equator

Solar energy

Cold deserts

Cold deserts

Forests

Forests

Forests

Hot deserts

Hot deserts

Westerlies

Westerlies

Northeast trades

Southeast trades

Air cools and

descends at

lower latitudes.

Warm air rises and

moves toward the

poles.

The highest solar energy

input is at the equator.

Air cools and

descends at

lower latitudes.

Figure 7-3 Global air circulation. The largest input of solar energy occurs at the equator. As this air is heated it rises

and moves toward the poles. However, the earth’s rotation deflects the movement of the air over different parts of

the earth. This creates global patterns of prevailing winds that help distribute heat and moisture in the atmosphere.