The Biosphere

Chapter 15.1 and 15.2

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

Biotic and abiotic factors interact in the biosphere.

• All four Earth systems are interconnected.

• The Gaia hypothesis considers Earth as a kind of living organism.– Earth systems interact

to yield a biosphere capable of supporting life.

– It was developed by James Lovelock and Lynn Margulis.

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

• A microclimate is the climate of a small specific place within a larger area.

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

90 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.