18. The Environment and us
Class 5 :EVS1
18. The Environment and Us.
EXERCISES
1. What's the solution?
Rivers and lakes are filled with water hyacinth.
Ans. If organic substances mix with water,
there is a growth of water plant like hyacinth.
But when it grows excessively it creats problems for other aquatic animals.
During day time, it releases oxygen but in the night it requires oxygen too. It causes the depletion of dissolved oxygen in the water and hence many other organisms in the water die fue to lack of oxygen. Their dead remains work as fertilizer and it grows in more quantities. Such water body get filled with water hyacinth.
To save the water body from such water hyacinth first of all it should be removed from water and stop the pollutants from mixing up in water by building bunds around the water body.
2. Use your brain power!
What would happen if no kites (birds) are left in a particular region? Which living things would increase in number?Which would decrease?
Ans: Kite is a bird of pray. They kill the small birds. They also eat dead and decaying animals.If kites will not be left in a particular region,then these smaller birds like rodents will increase in number.Kite is a top predator and so it is not food for others. Thus even if the number of kites fall,there will be little difference in any other animal's number.
Q.3. Answer the following questions.
1. Whay is meant by migration?
Ans.: When animals move from one place to other temporarily or permanently for the purpose of feeding themselves,it is calles migration.
2. Describe the lifecycle of birds.
Ans.: Both the parents (birds) build the nest for laying eggs. The female bird lays the eggs and she incubates the eggs for some time till the young one hatch out the eggs. Hatchings are cared for both the parents.They are fed by both. When the young one develop wings and are able to fly,they leave the nest and go away from the nest.
3. Give two causes of air pollution.
Ans: Following are the two causes of air pollution.
1. Burning of fuel in factories and industries cause smoke snd and pollutants.
2. Burning of fuel in vehicles cause air pollution.
4. For what purpose do we use land obtained by clearing forests?
Ans: Following are the purposes that we use land obtained by clearing forests.
1. For the purposes of constructing building, roads,dams, bridges, houses etc.
2. For the purpose of farming, Industries etc.
Q.4. Give reasons.
1. It is important to conserve the living components of the environment.
Ans.: Due to imbalance in environment the factors in the environment are getting destroyed. If one factor of environment is damaged, its relationship with othe factors also get disturbed. From time to time ,some of the living things on the earth become extinct. If it will be continued the whole world will be in danger so it is important to conserve the living components of the environment.
2.The numbers of wild animals are falling day by day.
Ans.: Due to human intervention in nature large scale changes are taking place in the air, water and land. Because of it the ecosystem has got disturbed , the cycle of food chain has disturbed. Because of deforestation most of the wild animals are getting destroyed or migrating. His is the reason that the numbers of wild animals are falling day by day.
Q.5. True or false.
A. Dead plants and animals are abiotic components.
Ans.: True
B. It is necessary to conserve biodiversity.
Ans.: True
Q.6 Classify the following as natural or man-made.
Soil, horse, stone, water hyacinth, book, sunlight, dolphin, pen, chair,water, cottonwool,table,trees, brick.
Ans.
Natural: Soil, horse, stone, water hyacinth, sunlight, dolphin, water, cottonwool,trees.
Man-made: book, pen, chair,water,table,brick.
18. The Environment and Us.
EXERCISES
1. What's the solution?
Rivers and lakes are filled with water hyacinth.
Ans. If organic substances mix with water,
there is a growth of water plant like hyacinth.
But when it grows excessively it creats problems for other aquatic animals.
During day time, it releases oxygen but in the night it requires oxygen too. It causes the depletion of dissolved oxygen in the water and hence many other organisms in the water die fue to lack of oxygen. Their dead remains work as fertilizer and it grows in more quantities. Such water body get filled with water hyacinth.
To save the water body from such water hyacinth first of all it should be removed from water and stop the pollutants from mixing up in water by building bunds around the water body.
2. Use your brain power!
What would happen if no kites (birds) are left in a particular region? Which living things would increase in number?Which would decrease?
Ans: Kite is a bird of pray. They kill the small birds. They also eat dead and decaying animals.If kites will not be left in a particular region,then these smaller birds like rodents will increase in number.Kite is a top predator and so it is not food for others. Thus even if the number of kites fall,there will be little difference in any other animal's number.
Q.3. Answer the following questions.
1. Whay is meant by migration?
Ans.: When animals move from one place to other temporarily or permanently for the purpose of feeding themselves,it is calles migration.
2. Describe the lifecycle of birds.
Ans.: Both the parents (birds) build the nest for laying eggs. The female bird lays the eggs and she incubates the eggs for some time till the young one hatch out the eggs. Hatchings are cared for both the parents.They are fed by both. When the young one develop wings and are able to fly,they leave the nest and go away from the nest.
3. Give two causes of air pollution.
Ans: Following are the two causes of air pollution.
1. Burning of fuel in factories and industries cause smoke snd and pollutants.
2. Burning of fuel in vehicles cause air pollution.
4. For what purpose do we use land obtained by clearing forests?
Ans: Following are the purposes that we use land obtained by clearing forests.
1. For the purposes of constructing building, roads,dams, bridges, houses etc.
2. For the purpose of farming, Industries etc.
Q.4. Give reasons.
1. It is important to conserve the living components of the environment.
Ans.: Due to imbalance in environment the factors in the environment are getting destroyed. If one factor of environment is damaged, its relationship with othe factors also get disturbed. From time to time ,some of the living things on the earth become extinct. If it will be continued the whole world will be in danger so it is important to conserve the living components of the environment.
2.The numbers of wild animals are falling day by day.
Ans.: Due to human intervention in nature large scale changes are taking place in the air, water and land. Because of it the ecosystem has got disturbed , the cycle of food chain has disturbed. Because of deforestation most of the wild animals are getting destroyed or migrating. His is the reason that the numbers of wild animals are falling day by day.
Q.5. True or false.
A. Dead plants and animals are abiotic components.
Ans.: True
B. It is necessary to conserve biodiversity.
Ans.: True
Q.6 Classify the following as natural or man-made.
Soil, horse, stone, water hyacinth, book, sunlight, dolphin, pen, chair,water, cottonwool,table,trees, brick.
Ans.
Natural: Soil, horse, stone, water hyacinth, sunlight, dolphin, water, cottonwool,trees.
Man-made: book, pen, chair,water,table,brick.
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