KEY CONCEPT The biosphere is one of Earth’s four interconnected systems.

The biosphere is the portion of Earth that is inhabited by life.

• The biosphere includes all ecosystems.

–one of Earth’s systems

– includes the biota, all the living things in the biosphere

There are three other Earth systems.

– hydrosphere—water, ice, and water vapor

– atmosphere—air blanketing Earth’s solid and liquid surface

– geosphere—geologic features above and below Earth’s surface

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

Climate is the prevailing weather of a region.

• Climate is the long-term pattern of weather conditions.– average temperature– precipitation– relative humidity

• Key factors shape an area’s climate.– temperature– sunlight– water– wind

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 ofEarth

– tropical zone: surrounds the equator

– temperate zone: the wide area in betweenthe polar and tropical zones

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

temperatetemperate

polarpolar

tropicaltropical

temperatetemperate

polarpolar

90o N

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

• Solar heating causes movements in both water and air.

–wind

–ocean currents• Earth’s rotation also has effects on

the winds and currents

• 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.

western slope eastern slope

– 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.

• Many organisms survive in a specific climate due to their adaptations.