Question

Explain why there is a need for a variety of animals and plants in a forest.

Answer 1

Plants give out oxygen through the process of photosynthesis. They help to maintain the balance of oxygen and carbon dioxide in the atmosphere. That is the reason that forests are called nature lungs.
Animals take food from plants and release energy and do useful work for the forest.

Complete answer:
Forests are very helpful for us. They clean air, play a vital role in the water cycle, provide various items and so on.
Many different kinds of animals are necessary for their survival and maintenance of the food chain. For example, grass is eaten and taken by insects, which in turn, are eaten by the frog. The frog is consumed and eaten by snakes which are eaten by eagles. Thus, it forms a food chain. Grass -> insects -> frog > snake -> eagle.
Many food chains can be found present in the forest. All food chains are linked and interconnected. If anyone's food chain is damaged, it affects other food chains. Every part of the forest is dependent on the other parts. If we remove one component, say trees, all other components would be affected.
Animals help in dispersing seeds of many different plants. The decaying animal dung also gives nutrients to the seedling to grow. This is the way in which animals help the forest to grow and regenerate.
If trees are absent, rain will hit the ground directly and may flood the area around it. Heavy rain may also deteriorate the soil. Roots of trees and grasses usually bind the soil together, but in their absence the soil will be washed away or eroded. Plants function as natural absorbers of rainwater and allow water to seep slowly. Plants prevent soil erosion. In this way forest helps in preventing floods.
The micro-organisms which convert and act on the dead plants and animals to humus are known as decomposers. Bacteria. Mushrooms etc. are some perfect decomposers. They decompose dead organisms and give nutrients to trees.

Note: In forests, many different types of plants and animals allow plants to regenerate and expand. Herbivores, which in connection act as food for carnivores, are provided by a greater variety of plants. Decomposers convert dead animals and plants into humus, while making sure the recycling of nutrients. This variety of diversity makes the forest a complex living organism.