15.1 Life in the Earth System 15. 1 15. 1 KEY CONCEPT The biosphere is one of Earth’s four interconnected systems. 15.1-15.5 merged!!

15.1 Life in the Earth System

15. 1 15. 1 KEY CONCEPT The biosphere is one of Earth’s four interconnected systems.

15.1-15.5 merged!!


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.


15.2 15.2 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.


15. 3 15. 3 KEY CONCEPT Biomes are land-based, global communities of organisms.


Earth has six major biomes.

• A biome is a major community of organisms.


• Tropical rain forest biomes produce lush forests.– warm temperature– abundant

precipitation all year

Source: World Meteorological Organization


• Grassland biomes are where the primary plant life is grass.

Rapid City, South Dakota

Source: National Oceanic Atmospheric Administration


– Temperate grasslands are dry and warm during the summer; most precipitation falls as snow.

• Grassland biomes are where the primary plant life is grass.

– Tropical grasslands are warm through the year, with definite dry and rainy seasons.


• Desert biomes are characterized by a very arid climate.– very low amount of

precipitation– four types: hot, semi-

arid, coastal, and cold

Tucson, Arizona



• Temperate forest biomes include deciduous forests and rain forests.– Temperate deciduous forests have hot summers and

cold winters.– Deciduous trees are the dominant plant species.


Burlington, Vermont


– Deciduous trees are the dominant plant species.– The temperate rain forests have a long wet season and

relatively dry summer.

• Temperate forest biomes include deciduous forests and rain forests.– Temperate deciduous forests have hot summers and

cold winters.

– Ferns and moss cover the forest floor.


• The taiga biome is located in cooler northern climates.– boreal forest– long winters and short

summers– small amount of

precipitationSource: Environment Canada

Banff, Canada


• The tundra biome is found in the far northern latitudes with long winters.– winter lasts 10 months– limited precipitation– permafrost

Barrow, Alaska



• Minor biomes, such as chaparral, occur globally on a smaller scale.


Polar ice caps and mountains are not considered biomes.

• Polar ice caps have no soil, therefore no plant community. • The climate and organisms found on mountains change as

the elevation changes.


15.415.4 KEY CONCEPT Marine ecosystems are global.


– neritic zone—from intertidal zone to continental shelf

– bathyal zone—from neritic zone to base of continental shelf

– abyssal zone –lies below 2000 m

The ocean can be divided into zones.

• Ocean zones can be determined by their distance from shoreline and water depths.– intertidal zone—between low and high tide

intertidal zoneneritic zone

bathmatzone

abyssalzone


• The neritic zone harbors more biomass than any other zone.

• Plankton make up most of the biomass.– zooplankton– phytoplankton


Coastal waters contain unique habitats.

• Coral reefs are found in warm waters.– tropical climate zone– great amount of biomass


• Kelp forests are found in cold, nutrient-rich waters. – large communities of

seaweed– great amount of

biomass


15.5 15.5 KEY CONCEPT Freshwater ecosystems include estuaries as well as flowing and standing water.


Estuaries are dynamic environments where rivers flow into the ocean.

• An estuary is a partially enclosed body of water.– mixture of fresh water with salt water– Chesapeake Bay– Louisiana bayous


• Estuaries are highly productive ecosystems.

• Estuaries provide a protected refuge for many species.– birds migration– spawning grounds

• Estuaries are primarily threatened by land development.


Freshwater ecosystems include moving and standing water.

• A watershed is a region of land that drains into a body of water.

• Ecosystems may be different along a river’s course


• Wetlands are among the most productive ecosystems.– provide a home for many species– filter dirty water– renew underground water supply

• Some animals have adaptations suited to the freshwater they inhabit.


Ponds and lakes share common features.

• Freshwater bodies are divided into three zones.– littoral zone– limnetic zone– benthic zone


• All lakes “turn over” periodically.– Turn over happens due to changes in density.– In both autumn and spring, surface water flows

downward and bottom water flows upward.– The upwelling brings up nutrients.

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15.1 Life in the Earth System 15. 1 15. 1 KEY CONCEPT The biosphere is one of Earth’s four interconnected systems. 15.1-15.5 merged!!