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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. 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