D1.1_Earth_Our_Biosphere

Science 10 Unit D: Energy Flow in Global Systems

Weather vs. Climate

  • Weather: Specific atmospheric conditions at a particular location at a specific time.

  • Climate: Average weather conditions in a region measured over several years.

  • Key Factors:

    • Temperature

    • Precipitation

    • Cloud cover

    • Humidity

The Biosphere

  • Definition: The narrow zone around Earth that can support life.

  • Components:

    • Atmosphere: The layer of gases surrounding Earth.

    • Hydrosphere: All water bodies and moisture on Earth.

    • Lithosphere: The solid outer layer of Earth (land).

  • Includes both:

    • Biotic Components: Living things.

    • Abiotic Components: Non-living environmental elements.

Composition of the Atmosphere

  • Percent Composition of Atmosphere:

    • Nitrogen: 78.08%

    • Oxygen: 20.95%

    • Other gases: 0.97%

  • Key Point: Most of Earth's atmosphere is composed of nitrogen gas.

Layers of the Atmosphere

Overview of Atmospheric Layers:

  1. Troposphere

    • Extends from surface to 10 km.

    • Contains 80% of atmospheric gases.

    • Temperature ranges from 15°C to -60°C (decreases with altitude).

    • Home to most living organisms.

    • Inversion: A reversal of the temperature change with altitude, trapping colder air near the ground.

  2. Stratosphere

    • Extends from 10 km to 50 km.

    • Contains the ozone layer.

    • Temperature ranges from -60°C to 0°C.

    • An exothermic process converts stratospheric oxygen to ozone:

      • O2(g) -> O3(g) (absorption of ultraviolet radiation increases temperature).

  3. Mesosphere

    • Extends from 50 km to 80 km.

    • Temperature ranges from 0°C to -100°C.

    • Contains traces of water vapor.

  4. Thermosphere

    • Extends from 80 km to 300 km.

    • Temperature ranges from -100°C to 1500°C.

    • Very little gas present.

Summary of Earth Systems

  • Atmosphere (air)

  • Biosphere (living organisms)

  • Hydrosphere (water)

  • Lithosphere (earth)

Additional Study Information

  • Read pages 342 – 348

  • Complete D1.1 Check and Reflect on page 348, numbers 1 – 12.