Biology - Natural Resources


  • The resources, available on the Earth and the energy being received from the Sun, are essential to meet the basic necessities of all life-forms on the Earth.

  • The biotic component incorporates all living of the biosphere.

Biotic Component
  • The abiotic component incorporates the air, the water, and the soil of the biosphere.

Biogeochemical Cycles

  • Biogeochemical cycles explain a constant interaction between the biotic and abiotic components of the biosphere.

  • Biogeochemical cycles are a dynamic phenomenon that helps to maintain the stability in the ecosystem.

  • The significant biogeochemical cycles are −

    • Water Cycle

    • Carbon Cycle

    • Nitrogen Cycle

    • Oxygen Cycle

  • Let’s discuss each of them in brief −

Water Cycle

  • The whole process, starting from the water evaporation, rainfall to flowing back into the sea via rivers, is known as the water-cycle.

Water Cycle
  • As shown in the image given above, water cycle is a complex phenomenon. During the process of water cycle, it helps ecosystem by maintaining its balance.

  • Water cycle helps in making new fertile soil, increasing the fertility of soil, providing nutrition to the biotic components in different ecological regions, etc.

Carbon Cycle

  • Carbon is found on the Earth in various forms, such as diamond and graphite (in solid form) and in combined state i.e. carbon and dioxide (as a gas).

  • Carbon is one of the essential elements for the photosynthesis.

Carbon Cycle
  • The process of photosynthesis converts carbon dioxide, which is present in the atmosphere or dissolved in water into glucose molecules.

  • The glucose provides energy to living things that involves the process of respiration.

  • In the process of respiration, oxygen may or may not be used to convert glucose back into carbon dioxide.

  • Lastly, the carbon dioxide goes back into the atmosphere.

Nitrogen Cycle

  • About 78 percent part of our atmosphere is shared by nitrogen alone.

  • Nitrogen is a part of many molecules, which are essential for the life.

  • There are a few varieties of bacteria that help in nitrogen-fixing.

  • These special bacteria convert the comparatively inert nitrogen molecules into nitrates and nitrites essential for the life in direct or indirect way.

  • The nitrogen-fixing bacteria are largely found in the roots of legumes.

Oxygen Cycle

  • In the total constituents of our atmosphere, about 21 percent is shared by oxygen.

  • Oxygen is also found in the Earth’s crust.

  • Oxygen is an essential component of most of the biological molecules, including carbohydrates, nucleic acids, proteins, and fats (or lipids).

  • Oxygen, present in the atmosphere, is used especially up in the three following processes −

    • Combustion

    • Respiration

    • Formation of oxides of nitrogen

Oxygen Cycle
  • Oxygen is returned back to the atmosphere by the process of photosynthesis.

  • Oxygen is lifeline of most of the organisms found on the earth, but for some bacteria, it is poisonous.