Science 3 Marks Question

Forests are called the green lungs. This is because plants in forests release oxygen through the process of photosynthesis and help in providing oxygen to animals for respiration. Plants consume carbon dioxide released by the animals. In this way, plants help in maintaining a balance of oxygen and carbon dioxide in atmosphere

Decomposers are micro-organisms that convert the dead plants and animals to humus.

Bacteria and fungi are the two types of decomposers.

They help in the process of recycling of nutrients by decomposing various dead organisms such as plants and animals to form humus.

Forest acts as a natural absorber of water. It allows rain water to seep through. In the absence of trees, the rain water would hit the ground directly resulting in flood. However, because of the presence of trees, rain water does not hit the ground directly. It rather hits the ground slowly. Hence, before flooding, all the rain water seeps through ground. In this way, forests prevent floods.

Population explosion: Large areas of forests have been cleaned for agriculture, factories, road and rail tracks, industries, mining and quarrying have seriously affected the forest. Expanding agriculture is one of the most important causes of deforestation. As demands on agricultural products rise more and more land is brought under cultivation for which forests are cleared, grass-lands ploughed, uneven grounds levelled, marshes drained and even land under water is reclaimed. Forest fires also destroy trees, seeds and the animal life. A part from these Grazing and gnawing mammals trample the young plants, and damage their trunks and roots. Deforestation can endanger our life and environment.

We should worry about the conditions and issues related to forests far from us because forests influence climate, water cycle and air quality of planet earth in a big way. Forests provide us with oxygen. If forests disappear, the amount of carbon dioxide in air will increase, resulting in the increase of earth’s temperature. They provide habitat to a large number of animals. In the absence of trees and plants, the animals will not get food and shelter. They protect soil. In the absence of trees, the soil will not hold water, which will cause floods. Forests help in bringing good rainfall in neighbouring areas. They are a source of medicinal plants, timber and many other useful products.

Forest products play vital role in socio-economic development. We get food (cereals, pulses and fruits), fire wood, fibre, construction material, industrial products (tannins, lubricants, dyes, resins and perfumes) and products of medicinal importance. It is also the home of diverse wildlife which maintains the ecosystem. Forests give oxygen to keep us alive and absorb carbon dioxide and it also help in maintaining water cycle in nature. Forests save the soil from erosion and help in maintaining the ground water level. Thus, forests are valuable resources.

Forest acts as a natural absorber of water. It allows rain water to seep through. In the absence of trees, the rain water would hit the ground directly resulting in flood. However, because of the presence of trees, rain water does not hit the ground directly. It rather hits the ground slowly. Hence, before flooding, all the rain water seeps through ground. In this way, forests prevent floods.

Forests provide us with oxygen. They protect soil and provide habitat to a large number of animals. Forests help in bringing good rainfall in neighbouring areas. They are a source of medicinal plants, timber and many other useful products. By the process of transpiration and photosynthesis, forests maintain the temperature. Forests provide shelter for the animals and act as a protective camouflage. Forests provide shelter and food to the tribes living in the jungle. Forest trees such as the bamboo are used in making furniture, baskets, ladders, etc. The teak tree is used to make furniture. The Neem tree is used for medicinal purposes. Forests also provide wood to make paper and other products such as gum, wax, rubber, and honey. Forest influence climate, water cycle and air quality. Forests play a very important role in the food chain. When forests are affected, they affect living beings such as animals and plants.

There is no waste in a forest because micro-organisms act on the wastes and convert them to humus. This humus ensures that the nutrients are returned back to the soil.

Deforestation leads to floods as lesser number of trees will be available due to the deforestation. In the absence of trees and plants of the forest, the excessive amount of rainwater falling during heavy rains cannot be absorbed into forest ground. The large amount of rainwater will then suddenly flow into rivers causing the flooding of rivers.

Decomposers are micro-organisms that convert the dead plants and animals to humus. Bacteria and fungi are the two types of decomposers. They help in the process of recycling of nutrients by decomposing various dead organisms such as plants and animals to form humus.

Here is a figure showing two animals, two birds and a few trees as a part of forest:

A greater variety of plants and animals in the forests helps it to regenerate and grow. Greater variety of plants means more food and habitat for the herbivores. An increase in herbivores means more food for carnivores. Decomposers help to maintain the supply of nutrients to the soil and to the growing plants. This wide variety makes forest a dynamic living entity.

The papers are made from wood pulp. We derive wood by cutting down trees. If we recycling existing quantity of paper in the market and will not let it decompose, we can stop cutting of forest trees for new raw materials required for paper making.
It takes years to grow a tree and cutting a tree takes only few minutes.
So, we should give a serious thought before cutting a single tree even and should encourage recycling of papers every where in our country and in the world.

1. Sachin noticed the disturbance in the water cycle in his area like stream drying up. Pond water getting muddy, less availability of fuel wood, etc.
2. Deforestation.
3. Love for nature and environmental consciousness.

Nothing goes waste in a forest because of the following reasons:

1. Dry leaves and remains of dead animals are converted to a dark coloured substance called humus and increase the fertility of soil. The importance of humus to the soil is that it provide nutrients for the growth of plants.
2. Dead animals become food for vultures, crows, jackals and insects.
3. Broken branches of trees are used as fuel by the people living in the vicinity.

Forest provides home (shelter), food and water to the animals living there. There are a large number of various types of animals in the forest. The forests provide a natural habitat to animals. The different layers of regulation present in a forest provide food and shelter. Forest provides leaves, flowers, fruits, seeds, nuts and bark of trees as food for herbivorous animals. The carnivorous animals hunt and eat herbivorous animals. The dense bushes, tall grasses and thick trees provides shelter and also protection for herbivorous animals.

The seedling was being benefited from the animal dung as the decaying animal dung provided nutrients to the growing seedlings. This happens as follows-Animal dung or droppings keep on collecting on the forest floor. The decomposer organism (such as bacteria of fungi) act on animal wastes and convert them into humus.
The humus contains plant nutrients and it mixes with the forest soil and make it fertile, seeds obtain nutrients from forest soil and germinate to form seedlings and seedlings grow to form saplings.

• By not allowing overgrazing.
• Wildlife should be protected.
• Afforestation should be undertaken.
• Forest fires should be controlled.

The three activities going on in the forest on the basis of the given figure are:

1. Oxygen is given out by plant leaves.
2. Carbon dioxide is consumed by the plants to prepare their food by the process of photosynthesis.
3. Nutrients are being added to the soil by the action of decomposers.

• Loss of plants which provide herbs, medicines, fruits, etc.
• Global warming
• Destruction of ecosystem
• Soil erosion