1. Earth’s Life Support Systems

2. 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?

3. The Four Spheres
Earth’s life support systems are composed of four spherical systems:
Atmosphere
Hydrosphere
Geosphere
Biosphere

4. The Four Spheres Atmosphere
A thin spherical envelope of gases that surround the Earth’s surface.
Five sections:
Troposphere*
Stratosphere*
Mesosphere
Thermosphere
Exosphere

5. 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.

6. The Four Spheres Stratosphere Right above the Troposphere
Extend from the surface km.
Contains the ozone layer (O3)
Ozone filters out the UV rays from the sun
Without Ozone layer, life would start to deteriorate

7. The Four Spheres Hydrosphere Geosphere Biosphere
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.

8. Vegetation and animals Biosphere Crust Lithosphere Mantle Biosphere
Atmosphere
Biosphere
Soil
Rock
Crust
Lithosphere
Mantle
Biosphere
(living organisms)
Atmosphere
(air)
Figure 3.6
Natural capital: general structure of the earth showing that it consists of a land sphere, air sphere, water sphere, and life sphere.
Core
Mantle
Crust
(soil and rock)
Geosphere
(crust, mantle, core)
Hydrosphere
(water)
Fig. 3-6, p. 55

9. 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%)

10. 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
Rocky
Mountains
Great
Plains
Mississippi
River Valley
Appalachian
Mountains
Figure 3.7
Major biomes found along the 39th parallel across the United States. The differences reflect changes in climate, mainly differences in average annual precipitation and temperature.
Coastal chaparral
and scrub
Coniferous forest
Desert
Coniferous forest
Prairie grassland
Deciduous forest
Fig. 3-7, p. 55

11. Life Sustaining Factors
Life on Earth Depends on Three major Factors:
The one way flow of high quality energy
The cycling of matter or nutrients through parts of the biosphere.
Gravity

12. What happens to Solar Energy Reaching the Earth
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.
The energy that reaches the earth, warms the air, evaporates and cycles water.
1% generates wind
<0.1% is used in photosynthesis

13. What happens to Solar Energy reaching the Earth
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.

14. 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.

15. Solar radiation Lower Stratosphere (ozone layer) Greenhouse effect
Reflected by
atmosphere
Radiated by
atmosphere
as heat
UV radiation
Lower Stratosphere
(ozone layer)
Most
absorbed
by ozone
Troposphere
Visible
light
Heat radiated
by the earth
Figure 3.8
Solar capital: flow of energy to and from the earth. See an animation based on this figure at CengageNOW.
Heat
Absorbed
by the earth
Greenhouse
effect
Fig. 3-8, p. 56