Ecosystem

Q.2. What are the different types of Energy Flows in an Ecosystem?

Ans. Introduction: Energy flows can be defined as the flow of energy from one organism to the other. All the functions of the ecosystem are in some way related to the growth and regeneration of its plant and animal species. These linked processes can be depicted as the various cycles like water cycle, oxygen cycle, carbon cycle, nitrogen cycle and energy cycle.

a. Water cycle

Water cycle is the flow of water from the Earth to the atmosphere and back. When it rains, water is collected in ponds, rivers, sea or some of it percolates into the ground which is then absorbed by the plants. The plants use some of it and transpire the rest as water vapour into the atmosphere. As water vapour is lighter than air, it rises up. Formation of a cloud takes place when water and dust particles combine. Finally, when the cloud becomes dense (condensation), it rains. Precipitation is the end of the water cycle and the same processes repeat again. Due to excess usage of water, this cycle has been hampered causing delays in the rain cycle and leading to climatic changes.

b. Carbon Cycle

Carbon is present in both biotic and abiotic components. Plants regulate the carbon level in the environment. Plants take in carbon dioxide from the atmosphere for photosynthesis and produce carbohydrates which contain carbon. Animals feed on plants leading to transfer of carbon. When animals excrete, they return carbon in the soil. Also, when animals die, carbon is released into the soil. Thus carbon levels are again restored. The burning of fossil fuels (combustion) also releases carbon dioxide. The flow of carbon from the atmosphere to the plants and back is known as the Carbon Cycle.

c. Oxygen Cycle

Oxygen cycle represents the flow of oxygen. Plants release oxygen during photosynthesis, which is then taken in by animals for respiration. The oxygen cycle is closely related to the carbon cycle as the carbon dioxide released by the animals is taken up by the plants to release oxygen in return.

d. Nitrogen Cycle

When animals defecate or die, matter is broken down into smaller particles by fungi, bacteria, worms and other organisms. Nitrogen fixing bacteria provide plants with substances like nitrates that can be absorbed and converted into proteins for animals to feed on. This allows for the flow of nitrogen from plants to animals and back to the plants. This cycle is known as the Nitrogen cycle.

e. Energy Cycles

Energy cycles are based on the principles of converting one form of energy to the other. For example, energy from sunlight is converted into energy for plants to grow leaves. This energy in turn can be utilised by herbivores as food. Energy cycles consist of food chains and food webs. The energy in the ecosystem can be depicted as a food/energy pyramid with tropic levels.

10% Rule: According to this rul herbivores intake only 10% of the energy and the rest is released as heat. Similarly, carnivores intake 10% of 10%, e., 1% of energy from herbivores.