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 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.

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

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 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

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

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

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.

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 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