Chapter 4: Ecosystems Chapter 4: Ecosystems and Communitiesand Communities

4-1: The Role of Climate4-1: The Role of Climate

CA Standard: 6.5eCA Standard: 6.5e: : Climate affects the Climate affects the

number and types of number and types of organisms that live in organisms that live in

an ecosystem.an ecosystem.

KEY CONCEPT KEY CONCEPT Climate is a Climate is a key key abioticabiotic factor that factor that affects the affects the

biosphere. biosphere.

What is Climate?What is Climate?•Weather: Day-to-day Weather: Day-to-day

condition of earth’s condition of earth’s atmosphere.atmosphere.– Clear, sunny one Clear, sunny one

day, but cold and day, but cold and cloudy the next.cloudy the next.

•Climate is the Climate is the long-term long-term patternpattern of weather conditions. of weather conditions.– average temperatureaverage temperature– precipitationprecipitation

•Key factors shape an area’s Key factors shape an area’s climate.climate.– sunlightsunlight– temperaturetemperature– waterwater– windwind

The Greenhouse EffectThe Greenhouse Effect

Carbon dioxide, water Carbon dioxide, water vapor, and a few other vapor, and a few other gases trap heat energy and gases trap heat energy and maintain Earth’s maintain Earth’s temperature range.temperature range.

These gases act like a These gases act like a greenhouse. This is called greenhouse. This is called the the greenhouse effect.greenhouse effect.

Sunlight

Earth’s Surface

Atmosphere

Some heat escapes into space

Greenhouse gases trap some heat

Greenhouse Greenhouse gases trap gases trap some heatsome heat

If greenhouse If greenhouse gases were not gases were not present in the present in the atmosphere, atmosphere, Earth would be Earth would be much cooler (30 much cooler (30 C)C)

•The Effect of Latitude on ClimateThe Effect of Latitude on Climate

•Solar radiation strikes different Solar radiation strikes different parts of Earth’s surface at an parts of Earth’s surface at an angle that varies throughout angle that varies throughout the year.the year.

•At the equator, energy from At the equator, energy from the sun strikes Earth almost the sun strikes Earth almost directly.directly.

•At the North and South Poles, At the North and South Poles, the sun’s rays strike Earth’s the sun’s rays strike Earth’s surface at a lower angle.surface at a lower angle.

Earth has three main climate zones:Earth has three main climate zones: •The three main zones are the polar, The three main zones are the polar,

tropical, and temperate climates.tropical, and temperate climates.– polar climatepolar climate: the far northern: the far northern

and southern regions of earth.and southern regions of earth.– tropical zonetropical zone: surrounds the equator.: surrounds the equator.– temperate zonetemperate zone: the wide area in : the wide area in

between the polar and tropical between the polar and tropical zones.zones.

• Earth’s Main Climate ZonesEarth’s Main Climate Zones

Sunlight

Most direct sunlight

90°N North Pole

Temperate

Tropical

Temperate

Polar

Arctic Circle

Tropic of Cancer

Equator

Tropic of Capricorn

Antarctic Circle

90°S South Pole

66.5°S

23.5°S

23.5°N

66.5°N

Polar

Sunlight

Sunlight

Sunlight

0°

• The angle of the Sun’s rays help The angle of the Sun’s rays help determine an area’s climate.determine an area’s climate.

Did you know?Did you know?

If you lived at the north pole, If you lived at the north pole, you would have 24 hours of you would have 24 hours of daylight during the summer.daylight during the summer.

During the winter,you would have to get used to

24 hours of darkness!

North pole in winter, North pole in winter, LunchtimeLunchtime

•Earth’s tilt on its axisEarth’s tilt on its axis plays a role plays a role in seasonal change.in seasonal change.

• If the earth was not tilted, there If the earth was not tilted, there would be would be no seasonsno seasons..

•Heat Transport in the BiosphereHeat Transport in the Biosphere– Unequal heating of Earth’s Unequal heating of Earth’s

surface drives winds and ocean surface drives winds and ocean currents, which transport heat currents, which transport heat throughout the biosphere.throughout the biosphere.

• Warm air over the equator rises, while Warm air over the equator rises, while cooler air over the poles sinks toward cooler air over the poles sinks toward the ground.the ground.

• The upward and downward movement The upward and downward movement of air creates air currents, or winds, of air creates air currents, or winds, that move heat throughout the that move heat throughout the atmosphere.atmosphere.

– The Earth’s polar zones are cold becauseThe Earth’s polar zones are cold because

• they are never heated by the sun.they are never heated by the sun.

• at the poles, the sun's rays are at a very at the poles, the sun's rays are at a very low angle.low angle.

• the greenhouse effect does not occur at the greenhouse effect does not occur at the poles.the poles.

• heat is transported from the poles to heat is transported from the poles to the equator.the equator.

–The upward movement of warm air The upward movement of warm air and the downward movement of and the downward movement of cool air creates cool air creates

• upwellings.upwellings.

• air currents.air currents.

• ocean currents.ocean currents.

• the greenhouse effect.the greenhouse effect.

– Earth's temperature range is Earth's temperature range is maintained bymaintained by

• the greenhouse effect.the greenhouse effect.

• climate zones.climate zones.

• ocean currents and winds.ocean currents and winds.

• latitude differences.latitude differences.

–Variation of temperature in the Variation of temperature in the temperate zone is due primarily totemperate zone is due primarily to

• air and ocean currents.air and ocean currents.

• the greenhouse effect.the greenhouse effect.

• variation in the sun’s energy variation in the sun’s energy production.production.

• latitude and season.latitude and season.

– The tropical zone is warm all year long The tropical zone is warm all year long becausebecause

• the sun’s angle changes the most in that the sun’s angle changes the most in that part of Earth.part of Earth.

• ocean water is warmest near the equator.ocean water is warmest near the equator.

• it receives direct or nearly direct sunlight it receives direct or nearly direct sunlight year-round.year-round.

• landmasses in the tropic latitudes hold on landmasses in the tropic latitudes hold on to heat.to heat.

• Landmasses shape inland climates. – larger changes larger changes

in temperaturesin temperatures– less less

precipitationprecipitation

• Oceans shape Oceans shape coastal climates.coastal climates.– smaller changes smaller changes

in temperaturesin temperatures– higher humidityhigher humidity– more more

precipitationprecipitation

• Mountains have an effect on climate.Mountains have an effect on climate.

western slope eastern slope

– Precipitation occurs on the side of the Precipitation occurs on the side of the mountain facing the wind.mountain facing the wind.

– On the downwind side, drier and On the downwind side, drier and cooler air produce a rain shadow.cooler air produce a rain shadow.

– A rain shadow is an area of decreased A rain shadow is an area of decreased precipitation.precipitation.

San Bernardino

High Desert (Victorville)

San Bernardino

Hesperia

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