DAV Class 7 SST Chapter 6 Question Answer – Life on the Earth

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DAV Class 7 SST Ch 6 Question Answer – Life on the Earth

DAV Class 7 SST Ch 6 Solutions – Life on the Earth

Something To Know

A. Tick (✓) the correct option.

Question 1.
Which one of the following is a threat to ecological balance?
(a) plantation
(b) wildlife protection
(c) population growth
(d) growing crops
Answer:
(c) population growth

Question 2.
Taiga is
(a) a Russian name for evergreen coniferous forests.
(b) an animal living in the polar region.
(c) a softwood tree.
(d) a cold desert area.
Answer:
(c) a softwood tree.

Question 3.
For the preservation of varied plant and animal life, the government has set up various
(a) zoological parks
(b) industrial parks
(c) national parks
(d) adventure parks
Answer:
(c) national parks

Question 4.
Mosses and lichens are
(a) commonly found vegetation in the polar regions.
(b) trees found in tropical deciduous forests.
(c) insect-eating animals.
(d) animals having thick fur on their body.
Answer:
(a) commonly found vegetation in the polar regions.

Question 5.
The temperate grasslands of North America are called the
(a) Atacama
(b) veld
(c) prairies
(d) campus
Answer:
(c) prairies

B. Fill in the blanks.

1. The first form of life appeared in the ………….. belonging to flora world.
2. The living zone of the planet earth is known as …………….
3. The human beings, who first appeared on the earth, were known as ……………
4. The Taiga vegetation is also known as …………..
5. The plants prepare their own food and are known as …………… of the biosphere.
Answer:
1. water bodies
2. biosphere,
3. Homosapiens
4. coniferous forests
5. food factories.

C. Write True or False for the following statements.

1. In the grasslands, the number of animals is less as compared to those in the equatorial forest.
2. Afforestation causes rise in the pollution level in the atmosphere.
3. Tigers and lions are the endangered species in India.
4. Pampas are the temperate grasslands in Australia.
5. Insect-eating animals are most commonly found in the dense forests of the equatorial region.
Answer:
1. False
2. False
3. True
4. True
5. True

D. Answer the following questions in brief.

Question 1.
Name the major types of vegetation of the world.
Answer:
Forests, grasslands, bushes, shrubs.

Question 2.
Name some common plants found in cold and hot desert regions of the world.
Answer:
Cold Deserts. Cactus, shrubs, bushes. Warm Deserts. Mosses, lichens.

Question 3.
What are the major components of ecosystem?
Answer:
Biotic and abiotic are two major components of ecosystem.

Question 4.
Give some examples of trees having needle-shaped leaves.
Answer:
Pine, fir and spruce.

Question 5.
Why do animals in the polar region have thick fur on their bodies?
Answer:
Animals in polar regions have thick fur on their bodies which protects them from extreme cold.

E. Answer the following questions.

Question 1.
Why are equatorial forests known as evergreen forests? Give a few examples of trees found there.
Answer:
Equatorial forests remain green throughout the year. Therefore, these forests are known as evergreen forests. Examples of trees found there – ebony, rosewood, rubber, mahogany, etc.

Question 2.
What role do plants play in ecological balance?
Answer:
The interrelation between plants and animals in the natural environment is called an ecosystem. The plants are primary producers and prepare their own food in the presence of the sun by taking nutrients from soil, moisture and carbon dioxide from the atmosphere. The plant kingdom supports animal kingdom especially the herbivores, which are large in number and reproduce faster. They are first-level consumers. The herbivores are consumed by carnivores which are second-level consumers.

Yet another category is omnivores which consume both plant and animal matters. The process of consuming plants by herbivores and herbivores by carnivores is referred to as food chain. The dead plant matter-leaves, fallen branches, rotten roots and animal matter-droppings, dead animals and birds are decomposed or decayed by bacterial action. They are known as decomposers. Decomposers keep the natural environment clean because they convert the dead matter of plants and animals into simple compounds which then enter the soil or air. This releases materials back to the environment.

Question 3.
Distinguish between tropical and temperate grasslands.
Answer:

Tropical Grasslands:	Temperate Grasslands:
(a) These are located between the equatorial forests and hot deserts in both hemispheres.	(a) These grasslands are located in the temperate zone and in the interior parts of the continents.
(b) These grasslands receive about 100 cm rainfall.	(b) These grasslands receive about 25 to 75 cm rainfall.
(c) The grasses of these regions are very rough, thick and tall.	(c) The grasses of these regions are soft and short.
(d) Example-Campos in Brazil.	(d) Example-Prairies in North America, Pampas in South America.

Question 4.
Distinguish between Hot and cold Deserts.
Answer:

Hot Desert:	Cold Desert:
(a) Hot deserts are mostly located on the western margins of the continents where temperature remains very high throughout the year.	(a) Cold deserts are mostly found around the polar regions where temperature remains below freezing point for the major part of the year.
(b) The common vegetation is comprised of cactus, shrubs and bushes.	(b) The common vegetation is comprised of mosses and lichens.
(c) The Sahara desert in Africa, the Thar desert in India and the Atacama in S. America are hot deserts.	(c) The Northern part of Siberia in Russia and northern part of Canada are cold deserts.

Question 5.
What are the various problems related to the ecological imbalance? What steps should we take to solve them? .
Answer:
The following problems are related to the ecological imbalance:
(a) The area under the forest cover is fast decreasing.
(b) The pollution level in different countries is rising alarmingly.
(c) Global temperature is rising, as the result of a few glaciers have started melting in the polar ice-caps.
(d) A few species like tigers, lions, etc. are facing the danger of extinction.

The following steps should be taken to solve the above problems:
(a) Afforestation should be taken up on a large scale.
(b) The pollution level should be decreased by not increasing the number of vehicles. Expansion of industries should also be controlled.
(c) Hunting of animals should be strictly banned.
(d) Several wildlife sanctuaries, national parks and biosphere reserves have been established by the government.

Value-Based Question

The Asiatic lion, once found across a vast area, is today crammed into a small scrubby forest of Gir in the south of Gujarat. Today, violence towards nature has caused retreat of forests, endangered species and also various sufferings to the mankind. Clearly the ideals of reverence for life have been renounced in favour of a materialistic way of life that justifies the destruction of nature and man both.

• What values should be adopted in life for preservation of plant and animal diversity?
• How far do you agree/disagree with those who justify destruction of nature and man both?

Answer:
Do yourself.

Map Skill
On the outline map of the world, label
(a) Tropical Evergreen Forests
(b) Tropical Deciduous Forests
(c) Tropical Grasslands
(d) Temperate Grasslands
(e) Hot Deserts
(f) Cold Deserts
(g) Coniferous Forests
Answer:
See these features along with some other in the following map.

Something To Do

Question 1.
Collect some interesting information and pictures related to India’s national parks and wildlife sanctuaries.
Answer:
Do yourself.

Question 2.
Collect information about three species of animals or plants facing the danger of extinction.
Answer;
Some species of animals which are facing the danger of extinction-Blackbuck, crocodile, Indian wild ass, lion, tailed macaque, Indian rhino and Sangai. Some species of plants which are facing the danger of extinction: madhuca insignis which is a wild variety of mahua and Hubbardia heptaneuron which is a species of grass.

Question 3.
Wildlife Week is celebrated all over the country in the month of October from 2nd to 8th every year . Here are a few projects and events for you to join the celebration of wildlife week (Choose any one).
(a) River or Beach clean up
(b) Community tree planting
(c) Create a schoolyard habitat
(d) A Habitat Garden in your own house
Answer:
Do yourself.

DAV Class 7 Social Science Chapter 6 Question Answer – Life on the Earth

A. Tick (✓) the correct option.

Question 1.
Plants prepare their own food with the help of
(a) sunlight
(b) air
(c) water
(d) All of them
Answer:
(d) All of them

Question 2.
In the equatorial region, trees are
(a) tall and dense
(b) short and dense
(c) tall and rare
(d) soft and soft
Answer:
(a) tall and dense

Question 3.
Rubber is a
(a) tropical deciduous tree
(b) tropical evergreen tree
(c) tropical grassland
(d) temperate softwood tree
Answer:
(b) tropical evergreen tree

Question 4.
The group of trees that grows in tropical deciduous forests is
(a) ebony, mahogany, rosewood
(b) sal, teak and bamboo
(c) cactus, shrubs and bushes
(d) pine, fir and spruce
Answer:
(b) sal, teak and bamboo

Question 5.
One of the following animals which does not belong to the polar region is
(a) penguin
(b) yak
(c) armadillos
(d) fox
Answer:
(c) armadillos

Question 6.
Spruce grows in
(a) coniferous forests
(b) cold deserts
(c) grasslands
(d) tropical forests
Answer:
(a) coniferous forests

Question 7.
Veld is a temperate grassland, located in
(a) Australia
(b) North America
(c) South America
(d) South Africa
Answer:
(d) South Africa

Question 8.
Which one of the following grasslands is located in Brazil?
(a) Pampas
(b) Prairies
(c) Campos
(d) Downs
Answer:
(c) Campos

Question 9.
The Atacama hot desert lies in
(a) India
(b) South America
(c) Africa
(d) Canada
Answer:
(b) South America

Question 10.
Taiga vegetation is found in
(a) deserts
(b) equatorial regions
(c) coastal regions
(d) high altitudes
Answer:
(d) high altitudes

B. State whether the following statements are True or False.

1. Pampas in South America is an example of temperate grassland.
2. The animal kingdom is also known as fauna.
3. Hot deserts are a common feature of the polar region.
4. The pollution level in different countries is rising.
5. Tropical deciduous forests shed their leaves in dry season.
6. Cutting of forests does not disturb the ecological balance.
Answer:
(i) True
(ii) True
(iii) False
(iv) True
(v) True
(vi) False.

C. Very Short Answer Type Questions

Question 1.
How do animals support the growth of plants?
Answer:
Animals provide soil nutrients with their remains that support the growth of plants.

Question 2.
Why is plant and animal life limited in the desert areas?
Answer:
In the desert areas, high temperature and scanty of rainfall limit the growth of plant and animal life.

Question 3.
What does vegetation include?
Answer:
‘Vegetation includes forests, grasslands, bushes and shrubs.

Question 4.
What are the main areas of tropical evergreen forest’s?
Answer:
The main areas of these forests are Zaire basin in Africa, Amazon basin in South America and a few islands in the south-east Asia.

Question 5.
What causes the growth of thick forests in the equatorial region?
Answer:
The equatorial region receives heavy rainfall throughout the year and the temperature remains very high. As a result, thick forests grow in this region.

Question 6.
Where are tropical grasslands located?
Answer:
They are located between the equatorial forests and hot deserts in both the hemispheres.

Question 7.
Name the common vegetations of hot deserts.
Answer:
Cactus, shrubs and bushes.

Question 8.
Name the common vegetations of cold deserts.
Answer:
Mosses and lichens.

Question 9.
Name three softwood trees.
Answer:
Pine, fir and spruce.

Question 10.
Why is a large variety of animals found in the equatorial region?
Answer:
It is because the forests in the equatorial region provide thick vegetation cover.

Question 11.
Name some animals found in grasslands.
Answer:
Lion, cheetah, leopard, deer and rabbit.

Question 12.
What is the characteristic feature of the animals found in the polar region?
Answer:
The animals of the polar region have thick fir on their body.

Question 13.
What has the Government of India done for preservation of different animal species?
Answer:
The Government of India has set up several wildlife sanctuaries, national parks and biosphere reserves for the preservation of different animal species.

Question 14.
Give the location of tropical evergreen forests.
Answer:
Tropical evergreen forests are located on both sides of the equator between 10° North and 10° South latitudes.

Question 15.
Name some common animals found in cold and hot desert regions of the world.
Answer:
Cold deserts-penguin, polar bear and yak. Hot deserts-Camel, horse and goat.

Question 16.
Why is human being considered as the most important part of the biosphere?
Answer:
It is because they derive all their basic needs from it.

D. Short Answer Type Questions

Question 1.
Give a brief description of temperate grasslands.
Answer:
Temperate grasslands are located in the temperate zone and in the interior parts of the continents. These grasslands receive about 25 to 75 cm rainfall. They sometimes receive snowfall also. The grasses of these regions are short and soft. They are known by different names in different areas, for example, Prairies in North America, Pampas in South America, Downs in Australia and Veld in South Africa.

Question 2.
Give a brief account of the vegetation that grows in the following forests:
(i) Tropical hardwood forests.
(ii) Deserts.
(iii) Temperate softwood forests.
Answer:
(i) Tropical hardwood forests: Ebony, rubber, mahogany, rosewood, sal, teak, bamboo, etc.
(ii) Deserts: Cactus, shrubs, bushes, mosses, licheus, etc.
(iii) Temperate softwood forests: Pine, spruce, fir, etc.

Question 3.
Give the characteristic features of the taiga vegetation.
Answer:
The taiga vegetation is found in high altitudes of Asia, Europe and North America. These are also known as coniferous forests.

Its characteristic features are:

• The taiga vegetation includes mainly cone-bearing trees.
• The trees are also conical in shape and have very soft wood.
• They have needle-shaped leaves.
• The main trees are pine, fir and spruce.

Question 4.
Define (a) Ecosystem (b) Desert.
Answer:
(a) Ecosystem: The relationship between plant kingdom, animal kingdom and human beings with their environment is known as ecosystem.
(b) Desert: A vast area, which has lost vegetation due to very scanty of rainfall, is known as desert.

Question 5.
Write a short note on Biosphere.
Answer:
Biosphere is a narrow zone of the Earth where land, water and air interact with each other to support life. All forms of life exist in this zone. Biosphere is divided into two kingdoms; namely, plant kingdom and animal kingdom which live together in complete harmony. In this zone, living things and non-living things are also dependent on each other for their existence. Plants prepare their own food with the help of non-living things like sunlight, air and water. They provide food for the animals to satisfy their basic needs. Animals, on the other hand, provide soil nutrients which help the plants in their growth.

E. Long Answer Type Questions

Question 1.
Distinguish between tropical evergreen forests and tropical deciduous forests
Answer:

Tropical Evergreen Forests:	Tropical Deciduous Forests:
(a) These forests thrive on both sides of the equator between 10° North and 10° South latitudes.	(a) These forests thrive between 10° North to 231/2° North and 10° South to 231/2° South latitudes.
(b) This forest belt receives heavy rainfall throughout the year and the temperature remains very high.	(b) This forest belt receives moderate rainfall.
(c) These forests remain thrughout the year.	(c) Trees of these forests shed their leaves in the dry season.
(d) Trees of these forests are very tall.	(d) Trees of these forests are of medium height.
(e) The main areas of these forests are Zaire basin in Africa, Amazon basin in South America and a few islands in the South-East Asia.	(e) The main areas of these forests are India, China and Eastern Brazil.

Question 2.
Give an account of the wildlife found in different regions of the world.
Answer:
The wildlife found in different regions of the world includes birds, insects or animals. The animals vaiy from place to place because of the variation in the natural environment. In the equatorial region, where the temperature and rainfall is high throughout the year, trees are tall and dense which help in the growth of a large variety of animals in this area.

The common animals found here are different types of monkeys, elephants, crocodiles and insect-eating animals like armadillos, snakes, etc. In grasslands, many animals are not found. The common animals are lion, cheetah, leopard, deer, rabbit, etc. In the polar region, the animals have thick fur on their body which protects them from extreme cold. The common animals found here are penguin, polar bear, yak, fox, etc.

Question 3.
Write a short note on the plant and the animal kingdom.
Answer:
For studying the plant kingdom, we can study different vegetation belts of the world. Vegetation includes forests, grasslands, bushes and shrubs. They vary from place to place because of the variation in climatic conditions. For example, in the equatorial region, where the temperature and rainfall is high throughout the year, trees are tall and dense.

This type of climatic condition helps in the growth of plant and animal life. On the other hand, in the desert areas, where temperature is high and rainfall is less, the plant and animal life is limited. The Vegetation belts of the world can broadly be divided into various groups on the basis of their location and climatic conditions.

These are Tropical Hardwood Forests, Grass¬lands, Deserts and Temperate Soft-wood Forests. Along with plants, animals also live in the biosphere. These can be birds, insects or animals. The animals vary from place to place because of the variation in the natural environment.The equatorial region receives heavy rainfall and the temperature is also high. With the result, tall and thick trees thrive here. As such, the forests in this region provide thick vegetation cover.

This makes it possible to have a large variety of animals here. The common animals found here are different types of monkeys, elephants, Jt crocodiles and insect-eating like armadillos, snakes, etc. In the grasslands, the number of animals is less as compared to the equatorial forests because of less vegetation. The common animals are lion, cheetah, leopard, deer, rabbit, etc. In the polar region, the animals have thick fur on their body to protect them from the extreme cold. The common animals found here are penguin, polar bear, yak, fox, etc.