Forests: Our Lifeline

Forests: Our Lifeline
1. Explain how animals dwelling in the forest help it grow and regenerate.
Animals help the forest to regenerate by helping in seed dispersal. The animals such as monkeys,
gibbons etc eat the fruits and spread the seeds in the forest. Their droppings make the soil fertile
by increasing humus in the soil. Insects help in pollination of the flowers.
2. Explain how forests prevent floods.
Forest also acts as a natural absorber of rainwater and allows it to seep into the soil. The plants
stop the rain water so that it seeps into the soil. Thus, water does not accumulate at a place
causing flood.
3. What are decomposers? Name any two of them. What do they do in the forest?
The micro-organisms which convert the dead plants and animals to humus are known as
decomposers. Examples- Bacteria and Fungi
In the forest they act on leaves and other organic matter present in the soil and release nutrients
in the soil. These nutrients (minerals) are again absorbed by the plants.
4. Explain the role of forest in maintaining the balance between oxygen and carbon dioxide
in the atmosphere.
Forests act as lungs of the environment. CO2 is produced by all the living organisms during
respiration. It is also produced during burning or materials such as coal, petrol and diesel.
The plants remove excess CO2 from the air and use it for photosynthesis. In return they release
O2. This oxygen is used by all the living beings for respiration.
Thus, the plants help in maintaining the balance between oxygen and carbon dioxide in the air.
5. Explain why there is no waste in a forest.
In a forest, the organic matter such as leaves, twigs and animal droppings are decomposed by
bacteria and fungi and mixed into the soil. The dead animals are eaten away by scavengers like
crows and vultures. So there is no waste in a forest.
6. List five products we get from forests?
We get the following products from the forestsa. Fire wood
b. Timber
c. Medicines
d. Sealing wax
e. Honey
7. Fill in the blanka. The insects, butterflies, honeybees and birds help flowering plants in pollination.
b. A forest is a purifier of air and water.
c. Herbs form the lowest layer in the forest.
d. The decaying leaves and animal droppings in a forest enrich the soil.
8. Why should we worry about the conditions and issues related to forests far from us?
We should worry about the conditions and issues related to forests far from us because we are
dependent on forests in many waysa. They maintain O2 and CO2 balance in the air.
b. They recharge the ground water.
c. They prevent soil erosion.
d. They provide medicines, timber, honey etc.
e. They are the dwelling places of many plants, animals and tribes.
9. Explain why there is a need of variety of animals and plants in a forest.
A variety of plants and animals in a forest gives a stable food web. This is because even if a few
organisms die, the food web will not get disturbed as the organisms will have many other options
for food.
10. In Fig. 17.15, the artist has forgotten to put the labels and directions on the arrows.
Mark the directions on the arrows and label the diagram using the following labelsclouds, rain, atmosphere, carbon dioxide, oxygen, plants, animals, soil, roots, water table
Clouds
Atmosphere
Rain
Plant
Animal
Roots
Soil
Water Table
11. Which of the following is not a forest product?
i. Gum
ii. Plywood
iii. Sealing wax
iv. Kerosene
12. Which of the following statements is not correct?
i. Forests protect the soil from erosion.
ii. Plants and animals in a forest are not dependent on one another.
iii. Forests influence the climate and water cycle.
iv. Soil helps forests to grow and regenerate.
13. Define Deforestation.
The excessive cutting of trees and plants in a forest is called deforestation.
14. What are the causes of deforestation?
Causes of deforestation area. Demand of fire wood and timber.
b. Construction of roads and buildings.
c. Industrial developments.
d. Overgrazing by animals.
15. What are the effects of deforestation?
The effects of deforestation area. The amount of CO2 increases in the atmosphere leading to rise in temperature of the earth.
b. In the absence of plants, rain water will not seep properly into the soil. Thus, water table will
go down. The rain water will cause floods.
c. Plant roots also hold soil and do not allow it to be carried away by wind or water. If plants are
cut down the soil will be carried away by wind and water. This will cause soil erosion.
d. The animals living in the forests will not get food and shelter.
e. Deforestation will endanger our life and environment.
16. What is crown of a tree?
The branchy part of a tree above the stem is known as the
crown of the tree.
17. What is a Canopy?
The tall trees form a green cover over other smaller plants in a forest. This cover is called
canopy.
Canopy
18. What is a food chain?
A chain of organisms in which the higher organism
eats the one that comes below it is called a food chain.
Grass
Grasshopper
Frog
Snake
Eagle
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K. P. Singh, Biology Department, Delhi Public School, Mathura Refinery Nagar, Mathura