Transcript Life Support Systems

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.
Vegetation
and animals
Atmosphere
Biosphere
Soil
Rock
Crust
Lithosphere
Mantle
Biosphere
(living organisms)
Atmosphere
(air)
Core
Mantle
Geosphere
(crust, mantle, core)
Crust
(soil and rock)
Hydrosphere
(water)
Fig. 3-6, p. 55
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%)
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.)
Denver
Baltimore
San Francisco
St. Louis
Coastal mountain
ranges
Sierra
Nevada
Great
American
Desert
Coastal chaparral Coniferous forest
and scrub
Rocky
Mountains
Desert
Great
Plains
Coniferous forest
Mississippi
River Valley
Prairie
grassland
Appalachian
Mountains
Deciduous forest
Fig. 3-7, p. 55
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.
Solar
radiation
Reflected by
atmosphere
Radiated by
atmosphere
as heat
UV radiation
Most
absorbed
by ozone
Lower Stratosphere
(ozone layer)
Visible
light
Troposphere
Heat
Absorbed
by the earth
Heat radiated
by the earth
Greenhouse
effect
Fig. 3-8, p. 56