Chapter 4: Ecosystems and Communities

4-1: The Role of Climate

CA Standard: 6.5e: Climate affects the number and types of organisms that live in an ecosystem.

KEY CONCEPT Climate is a key abiotic factor that affects the biosphere.

What is Climate? Weather: Day-to-day condition of earth’s atmosphere. Clear, sunny one day, but cold and cloudy the next.

Climate is the long-term pattern of weather conditions. average temperature precipitation Key factors shape an area’s climate. sunlight temperature water wind

The Greenhouse Effect

Carbon dioxide, water vapor, and a few other gases trap heat energy and maintain Earth’s temperature range. These gases act like a greenhouse. This is called the greenhouse effect.

Sunlight Some heat escapes into space If greenhouse gases were not present in the atmosphere, Earth would be much cooler (30 C) Greenhouse gases trap some heat Greenhouse gases trap some heat Atmosphere Earth’s Surface

The Effect of Latitude on Climate Solar radiation strikes different parts of Earth’s surface at an angle that varies throughout the year. At the equator, energy from the sun strikes Earth almost directly. At the North and South Poles, the sun’s rays strike Earth’s surface at a lower angle.

Earth has three main climate zones: The three main zones are the polar, tropical, and temperate climates. polar climate: the far northern and southern regions of earth. tropical zone: surrounds the equator. temperate zone: the wide area in between the polar and tropical zones.

Earth’s Main Climate Zones 90°N North Pole Sunlight Polar 66.5°N Arctic Circle Temperate Sunlight Tropic of Cancer 23.5°N Equator Most direct sunlight 0° Tropical Tropic of Capricorn 23.5°S Sunlight Temperate Antarctic Circle 66.5°S Sunlight Polar 90°S South Pole The angle of the Sun’s rays help determine an area’s climate.

you would have to get used to Did you know? If you lived at the north pole, you would have 24 hours of daylight during the summer. During the winter, you would have to get used to 24 hours of darkness!

North pole in winter, Lunchtime   North pole in winter, Lunchtime

Earth’s tilt on its axis plays a role in seasonal change. If the earth was not tilted, there would be no seasons.

Heat Transport in the Biosphere Unequal heating of Earth’s surface drives winds and ocean currents, which transport heat throughout the biosphere. Warm air over the equator rises, while cooler air over the poles sinks toward the ground. The upward and downward movement of air creates air currents, or winds, that move heat throughout the atmosphere.

The Earth’s polar zones are cold because they are never heated by the sun. at the poles, the sun's rays are at a very low angle. the greenhouse effect does not occur at the poles. heat is transported from the poles to the equator.

The upward movement of warm air and the downward movement of cool air creates upwellings. air currents. ocean currents. the greenhouse effect.

Earth's temperature range is maintained by the greenhouse effect. climate zones. ocean currents and winds. latitude differences.

Variation of temperature in the temperate zone is due primarily to air and ocean currents. the greenhouse effect. variation in the sun’s energy production. latitude and season.

The tropical zone is warm all year long because the sun’s angle changes the most in that part of Earth. ocean water is warmest near the equator. it receives direct or nearly direct sunlight year-round. landmasses in the tropic latitudes hold on to heat.

Landmasses shape inland climates. larger changes in temperatures less precipitation Oceans shape coastal climates. smaller changes in temperatures higher humidity more precipitation

Mountains have an effect on climate. Precipitation occurs on the side of the mountain facing the wind. On the downwind side, drier and cooler air produce a rain shadow. A rain shadow is an area of decreased precipitation. western slope eastern slope

High Desert (Victorville) San Bernardino High Desert (Victorville)

Rain shadow: The lack of rainfall on one side of a mountain range. Hesperia Rain shadow: The lack of rainfall on one side of a mountain range. San Bernardino