Earth's Biosphere: Life's Essentials

Earth - The Home of Humankind

• Biosphere is the sphere of life that spreads over all the other three spheres, providing essential requisites of life for all species, including light, heat, water, food, and living space or habitats.
• The term Biosphere was first used by Austrian geologist Edward Suess a century ago to describe the sphere of living organisms or biological processes lying at the interfaces between the atmosphere, lithosphere, and hydrosphere.
• Biosphere or ecosystem is an evolutionary system, representing a stable equilibrium of various physical and biological factors that have been operating in the past.

Nitrogen Cycle

• The Earth's atmosphere contains 78% nitrogen, which is essential for plant growth.
• Lack of nitrogen can cause serious damage to crop production.
• Nitrogen is absorbed by soil and from soil by plants for their growth.
• It is released into the atmosphere by the decomposition of dead animals in the form of ammonia.

Heat Cycle

• Heat is one of the prime requirements of life, supplied by solar radiation.
• The Earth receives only 45% of the solar energy that reaches the ground.
• 15% of solar energy is absorbed by the atmosphere, and 40% is reflected back into space.

Oxygen Cycle

• Oxygen not only supports life but also helps maintain ecological balance.
• Humans inhale oxygen and exhale carbon dioxide, which is essential for photosynthesis.