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The Changing EnvironmentCHAPTER 3.1

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OBJECTIVE

Describe ways in which the threelayers of the biosphere change overtime.

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The Changing Environment

Changes in the Lithosphere– Earth is approximately 4.5 billion years

old; humans are only 500,000 years– The lithosphere is made up of several

large, movable plates called TectonicPlates

– Liquid rock below the surface risesthrough cracks between the plates deepin the ocean floor

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Tectonic Plates

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Tectonic Plates

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The Changing Environment

Changes in the Lithosphere– The breaking down of rocks by

weather and water is calledWeathering

– The broken- down material is then carriedoff in the process of Erosion

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Erosion

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Erosion

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The Changing Environment

Changes in the Hydrosphere– Ice age is a long period of cooling during

which huge ice masses, called glaciers,grow and extend from Earth’s polarregions, covering much of the planet’ssurface

– During an ice age sea levels are lower and as glaciers melt, sea

levels rise

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The Changing Environment

Changes in the Hydrosphere– Movement of glaciers causes significant

changes in the shape of the land– scraping of the ice across the land

displaces rocks and results in large-scale weathering and erosion in

some areas deposit of materials in others

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The Changing Environment

Changes in the Hydrosphere– The Great Lakes and the peninsula of

Cape Cod are a result of the last ice age– No one knows what causes glaciers to

grow and then retreat

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Ice age

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The Changing Environment

Changes in the Hydrosphere– El Nino = a warm water current that is

nutrient-poor flows southward alongSouth America. Normally only for a fewweeks but can last months

– No one knows what causes El Nino

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El Nino

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El Nino

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El Nino

•Consequences of El Nino include:

•Short-term impact on global climate

•Impact on fish survival due to change inwater temperature and nutrient content

•Subsequent impact on economiesdependent on fisheries

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The Changing Environment

Changes in the Atmosphere– Sun light and Earth’s rotation about

its axis drive many of the daily as well asseasonal changes in the atm

– Before there was life there where manygases Water vapor Carbon dioxide } released from volcanoes Sulfur

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The Changing Environment

Changes in the Atmosphere– Organisms evolved that could combine

water, carbon dioxide, and energyfrom the sun to produce food

– (called PHOTOSYNTHESIS)– Photosynthesis released the first oxygen

into the air

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The Changing Environment

Changes in the Atmosphere– For 3.5 billion years oxygen, carbon

dioxide, water vapor, and nitrogen havebeen cycling from atmosphere toorganisms

– Carbon is also being cycled but much isbeing stored in the bodies of organisms,both alive and dead Living = forests, algae (I.e. Kelp “forests”) Non-living = fossil fuels (I.e. coal, oil)

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NitrogenCycling

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Nitrogen Cycling

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CarbonCycling

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The Changing Environment

Changes in the Atmosphere– Coal = a fossil fuel is stored carbon

from long-dead organisms– Burning organic matter releases

carbon and influences the temp. througha process called the Greenhouse Effect

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The Changing Environment

Changes in the Atmosphere– Humans change Earth’s atmosphere in

many ways Greenhouse Effect Loss of Ozone Increased pollution

– A natural cause that changes Earth’sAtmosphere and that has a global affectis Volcanic eruptions