Earth and Life Science Lecture Notes

Introduction to Earth Subsystems

• Focus on the subsystems of the Earth.
• Objectives:
  • Identify the four subsystems of the Earth.
  • Describe characteristics of each subsystem.
  • Understand the flow of matter and energy in these subsystems.
  • Reflect on stewardship of the subsystems.

Review of Earth's Uniqueness

• Earth is the only planet known to support life.
• Location in the solar system: ideal distance from the sun allows for a habitable zone.
• Key components for life:
  • Atmosphere protects from harmful radiation.
  • Water exists in liquid form.
• Earth is often referred to as the "water planet" or "blue planet" due to its vast oceans.

Components of Earth

• Key elements include:
  • Air: Wind, rain.
  • Water: Oceans.
  • Land: Rocky coasts, shores.
  • Life: Includes animals and plant life.

The Earth's Spheres

• The Earth consists of four subsystems:
  1. Atmosphere
  2. Biosphere
  3. Geosphere
  4. Hydrosphere

1. Atmosphere

• Gaseous layer composed of:
  • 78% Nitrogen
  • 21% Oxygen
  • Other gases (argon, carbon dioxide, etc.) make up 1%.
• Function:
  • Supports life by providing necessary gases.
  • Regulates climate and acts as a protective shield.
• Four layers of the atmosphere:
  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere

2. Biosphere

• Zone of life on Earth, includes:
  • Life in oceans, on land, and in water.
• Known as a large ecosystem.
• Vital for the continuation of life and ecological cycles.

3. Geosphere (Lithosphere)

• Solid portion of Earth, consists of:
  • Core, mantle, and crust.
• Provides minerals and habitats necessary for living organisms.
• Plays a role in tectonic activity, affecting the planet's dynamics.

4. Hydrosphere

• Comprises all water on Earth:
  • Oceans, glaciers, and atmospheric water.
• Oceans cover 71% of Earth's surface, mostly saltwater.
• Vital for sustaining life by providing necessary water resources.

Matter and Energy Flow

• Matter and energy continuously cycle through the Earth’s spheres:
  • Atmosphere provides heat for geosphere.
  • Biosphere receives energy and water from atmosphere and hydrosphere.
  • Interconnections are essential for sustenance of life.

Human Impact on Earth

• Rapid population growth since the 1700s has led to increased pollution.
• Importance of stewardship and conservation.

Assessment Questions

1. Best describes life forms in air, land, and sea?
   • Answer: Biosphere
2. Why are Earth’s cycles interconnected?
   • Answer: Because every organism has its own function.
3. Connection between biosphere and atmosphere?
   • Answer: Plants produce oxygen.
4. Composition of the atmosphere?
   • Answer: 21% oxygen and 78% nitrogen.
5. Where does ozone layer belong?
   • Answer: Atmosphere

Conclusion

• Review of the four interconnected subsystems: atmosphere, biosphere, geosphere, hydrosphere.
• Emphasis on their interdependence for sustaining life on Earth.