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Earth’s Life Support Systems
Questions for Today:
• What are the four major components of Earth’s Life Support?
• How do scientist classify Land and Water?
• What are the three factors that sustain life?
• What happens to solar energy reaching the Earth?
The Four Spheres
• Earth’s life support systems are composed of four spherical systems:– Atmosphere– Hydrosphere– Geosphere– Biosphere
The Four Spheres
• Atmosphere– A thin spherical envelope of gases that
surround the Earth’s surface.– Five sections:
• Troposphere*• Stratosphere*• Mesosphere• Thermosphere• Exosphere
The Four Sphere
• Troposphere– Extends from the surface of the earth to as
high as 17 km above sea level.– Contains the majority of the air we breathe.– Consists mostly of:
• Nitrogen (78%)• Oxygen (21%)
– The remaining one percent are composed of greenhouse gases.
• Water Vapor, Carbon Dioxide, and Methane.
The Four Spheres
• Stratosphere– Right above the Troposphere– Extend from the surface 17-50 km.
– Contains the ozone layer (O3)• Ozone filters out the UV rays from the sun• Without Ozone layer, life would start to deteriorate
The Four Spheres
• Hydrosphere– Consists of all water on or near the Earth’s
Surface– Covers 71-73% of the earth’s surface
• Geosphere– The Solid Earth– Core, Mantle, and Crust
• Biosphere– All the living aspects of the Earth– Extends 9 kilometers from the surface.
Fig. 3-6, p. 55
Rock
AtmosphereVegetationand animals
Lithosphere
Biosphere
Mantle
Crust
Soil
Biosphere(living organisms)
Geosphere(crust, mantle, core)
Mantle
Core
Hydrosphere(water)
Crust(soil and rock)
Atmosphere(air)
Life Exists on Land and in Water
• Biomes are large regions on the terrestrial earth with distinct climates and certain species adapted to them.
• Aquatic life zones are how scientist classify the water on Earth– Freshwater (2%)– Marine/Ocean (71%)
Fig. 3-7, p. 55
Average annual precipitation
100–125 cm (40–50 in.)75–100 cm (30–40 in.)50–75 cm (20–30 in.)25–50 cm (10–20 in.)below 25 cm (0–10 in.)
AppalachianMountains
Coastal mountainranges
Sierra Nevada
Great American
Desert
RockyMountains
GreatPlains
MississippiRiver Valley
Deciduous forestCoastal chaparraland scrub
Coniferous forest Desert Coniferous forest Prairie grassland
San Francisco
BaltimoreDenver
St. Louis
Life Sustaining Factors
• Life on Earth Depends on Three major Factors:1.The one way flow of high quality energy
2.The cycling of matter or nutrients through parts of the biosphere.
3.Gravity
What happens to Solar Energy Reaching the Earth
1. The energy reaches earth in the form of EM waves.
• Visible Light, UV, Infrared• Most of this energy is absorbed by the stratosphere
or reflected back into space• Only 5% makes it to the surface.
2. The energy that reaches the earth, warms the air, evaporates and cycles water.
• 1% generates wind• <0.1% is used in photosynthesis
What happens to Solar Energy reaching the Earth
3. 4% of the Sun’s energy is trapped within the ozone layer.
• This causes greenhouse gases to vibrate and release infrared radiation.
• The vibrating gas had high kinetic energy which warms the lower atmosphere and the surface of the earth
• Natural Greenhouse effect.
What Happens to Solar Energy reaching the Earth
• Human Activities, such as burning fossil fuels, increase the amount of greenhouse gases in our upper atmosphere.
• Studies have shown that these activities are increasing the natural greenhouse effect and warming the earth’s atmosphere.
Fig. 3-8, p. 56
Lower Stratosphere(ozone layer)
Solarradiation
UV radiation
Visiblelight Heat radiated
by the earth
Mostabsorbedby ozone
Absorbedby the earth
Greenhouseeffect
Reflected byatmosphere Radiated by
atmosphereas heat
Heat
Troposphere