NCERT Solutions for Class 8 Science Chapter 7 Conservation Of Plant And Animals

Q.1 Fill in the blanks.
(a) A place where animals are protected in their natural habitat is called _________ .
(b) Species found only in a particular area is known as _______ .
(c) Migratory birds fly to faraway places because of __________ changes.

Answer :

(a) A place where animals are protected in their natural habitat is called sanctuary.

(b) Species found only in a particular area is known as endemic.

(c) Migratory birds fly to faraway places because of climatic changes.

EXPLANATION :

(a) Wildlife sanctuary is the place where wild animals are protected from their predators and from poaching, in their natural habitat. Biosphere reserves are the areas that are used to conserve biodiversity like plants, animals and microorganisms. It also contains many wildlife sanctuaries and national parks.

(b) Any species whose range is restricted to a limited geographical area is called as endemic species. Species can be endemic to large or small areas of the world.

(c) Bird migration is the regular seasonal movement, which involves a flyway for breeding, food availability, habitat and weather. They migrate from their habitat region to far away places so as to find the favourable conditions to survive.

Q.2 Differentiate between the following.
(a) Wildlife sanctuary and biosphere reserve
(b) Zoo and wildlife sanctuary
(c) Endangered and extinct species
(d) Flora and fauna

Answer :

(a) DIFFERENCE BETWEEN WILDLIFE SANCTUARY AND BIOSPHERE RESERVE


WILDLIFE SANCTUARY

1) It is owned by the government or private agency that safeguards a particular species of birds and animals.

2) It is a natural habitat that provides protection and suitable living conditions to wild animals and birds.

3) Example :- Corbett National Park, Uttarakhand

BIOSPHERE RESERVE

1) A reserved area of land established by the government to protect the environment as a whole.

2) It helps in conservation of various life forms of plants, animals and microorganisms.

3) Example :- The Nilgiri Biosphere Reserve is an International Biosphere Reserve.


(b) DIFFERENCE BETWEEN WILDLIFE SANCTUARY AND ZOO


WILDLIFE SANCTUARY

1) It is owned by the government or private agency, that safeguards a particular species of birds and animals.

2) It is a natural habitat that provides protection and suitable living conditions to wild animals and birds.

3) Example :- Corbett National Park, Uttarakhand

ZOO

1) It is a place in which animals are kept for public exhibition.

2) It is an artificial habitat where animals may or may not adapt with the habitat.

3) Example :- Arignar Anna Zoological Park is India's largest zoo.


c) DIFFERENCE BETWEEN ENDANGERED SPECIES AND EXTINCT SPECIES


ENDANGERED SPECIES

1) An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction.

2) These species may be at risk due to factors such as habitat loss, poaching and invasive species.

3) Example :- Tiger Panthera tigris

EXTINCT SPECIES

1) Extinction of a particular animal or plant species occurs when there are no more individuals of that species in the world.

2) There are five major causes of extinction: habitat loss, an introduced species, pollution, population growth, and overconsumption.

3) Example :- Passenger pigeon Ectopistes migratorius


d) DIFFERENCE BETWEEN FLORA AND FAUNA


FLORA

1) Flora is all the plant life present in a particular region or time, generally the naturally occurring indigenous plants.

2) The flora liberates oxygen that is consumed by the fauna for respiratory activities.

3) India is home to more than 50,000 species of plants, including a variety of endemics.

FAUNA

1) Fauna is all of the animal life present in a particular region or time.

2) Fauna liberates carbon dioxide which is consumed by the flora for photosynthesis.

3) India is a megadiverse country which includes 91,000 species of animals.

Q.3 Discuss the effects of deforestation on the following.
(a) Wild animals
(b) Environment
(c) Villages (Rural areas)
(d) Cities (Urban areas)
(e) Earth
(f) The next generation

Answer :

Deforestation is the permanent removal of trees which includes clearing of the land for agriculture or grazing or using the timber for fuel, construction or manufacturing.

(a)Effects of deforestation on wild animals :

Plants forms an integral part of the ecosystem and these plants form the natural habitat of various animals which are also a part of this ecosystem. Destroying the plant life will ultimately threaten the existence of animals in that particular ecosystem and this may lead to their extinction.

(b)Effects of deforestation on environment :

Deforestation increases the temperature as well as increases pollution in the environment. With the increase in the carbon dioxide level and a decrease in the oxygen level, there is rise in global warming. It also lowers the level of ground water. Because the roots of trees and plants of a forest used to hold the water and thus maintains the ground water level. Moreover, deforestation decreases the soil fertility and increases soil erosion.

(c)Effects of deforestation in villages :

Deforestation results in the reduction of rainfall, decrease in soil fertility and also affects many factors which in turn increases the chances of natural disaster, thus affecting the people inhabiting in villages.

(d)Effects of deforestation in cities :

Deforestation results in global warming as there in an increase in the level of CO₂ which is a major green house gas. As CO₂ increases it traps more heat thus increasing the atmospheric temperature. It also results in the increase in respiratory diseases and cancer. Hence, deforestation also affects the life in cities.

(e)Effects of deforestation on Earth :

Deforestation decreases the fertility of soil thus changing the physical properties of soil. It also causes soil erosion thus increasing the chances of drought. All these changes result in desertification. Deforestation affects the wildlife adversely thus creating an imbalance of ecosystem.

(f)Effects of deforestation on the next generation :

Deforestation will majorly affect the life of next generation. Deforestation will result in a long term alterations in the climatic conditions that may even result in the extinction of life forms. There will be scarcity of food and a large amount of degradation of the environment. The coming generations won’t be able to see most of the animal as well as plant species due to their habitat loss.

Q.4 What will happen if
(a) we go on cutting trees
(b) the habitat of an animal is disturbed
(c) the top layer of soil is exposed

Answer :

(a)if we go on cutting trees :

then the temperature will increase to greater extent because there will be an instant rise in the level if CO₂ which will in turn trap more sunlight, thus increasing the atmospheric temperature leading to global warming. Global warming will cause melting of glaciers which will rise the water level. Increase in the level of green house gases will cause severe respiratory diseases and skin cancer.

(b)if the habitat of an animal is disturbed :

then the animals will lose their natural habitat and will start becoming endangered. They will move to another place in search of food, water, shelter and protection which in turn will cause ecological imbalance in that particular area.

(c)if the the top layer of soil is exposed :

then the exposed layer will lose all its nutrients, especially the humus which is the organic component of soil, formed by the decomposition of leaves and other plant material by soil microorganisms. The water holding capacity of soil will gradually decrease due to lack of soil nutrients.

Q.5 Answer in brief.
(a) Why should we conserve biodiversity?
(b) Protected forests are also not completely safe for wild animals. Why?
(c) Some tribals depend on the jungle. How?
(d) What are the causes and consequences of deforestation?
(e) What is Red Data Book?
(f) What do you understand by the term migration?

Answer :

(a) Biodiversity refers to the variety and variability of life forms such as plants, animals, and micro-organisms present in an area. Each and every organism depend upon one another for their survival. This means that the extinction of any organism will adversely affect the life of the other organism. Hence, we need to conserve biodiversity to maintain the ecological balance thus leading to the formation of a stable ecosystem.

(b) Protected forests are not completely safe for wild animals because people who live near by the forests or the people who are involved in illegal works, use these resources from forests to fulfil their own requirements. In this process, even the wild animals are killed to extract hide, ivory, fur, organs, skin, bones or teeth which can help them to earn a lucrative amount of money.

(c) The forests provide food, fodder and other resources to the tribal people which is helpful for them as well as for their cattle. Thus it is inevitable for them to depend on forests and their resources for everyday needs.

(d) The causes of deforestation are :

(i) Forests are cleared for accommodating the expanding urban areas and for fulfilling their ever-increasing requirements.
(ii) Forests are destroyed for implementing agriculture to feed the growing population and a place for animal husbandry that provides dairy products, egg, fish, meat etc.
(iii) Trees that are cut down, are used for as firewood by the tribal people living nearby the forest areas.

The consequences of deforestation are :

(i) Soil erosion.
(ii) Loss of biodiversity causing ecological imbalance.
(iii) Floods and droughts.
(iv) Sudden climate alterations due to increase of global warming
(v) Disruption of water cycle, thus reducing rainfall.

(e) Red Data Book is a state document established for documenting rare and endangered species of animals, plants, and fungi, as well as some local subspecies that exist within the territory. The Red Data Book contains the complete list of threatened species.

(f) Migration means the movement of a species from its own habitat to some other place during a certain period in a year for breeding or to overcome unfavourable climatic conditions.

Q.6 In order to meet the ever-increasing demand in factories and for shelter, trees are being continually cut. Is it justified to cut trees for such projects? Discuss and prepare a brief report.

Answer :

It's totally not justified to cut trees just to fulfill our needs. Trees are known as ‘the lungs of the earth’. They are the habitat of many living organisms, including animals. They provide us oxygen, and play a key role in maintaining the O₂-CO₂ level in the atmosphere. Their roots firmly bind to the soil and hence prevents soil erosion. They also reduce the chances of natural disasters like floods and droughts. They help us to conserve our rich biodiversity.

Cutting of trees causes an increase in the carbon dioxide (CO₂) level, which results in global warming. Moreover, it causes soil erosion, floods, the greenhouse effect, etc.

But if there is a serious need of clearing forests or cutting of a tree, then the agency or the company involved must take care of planting the same amount of trees with a deal of taking care of their nourishment and nutrients till they grow and become trees.

Q.7 How can you contribute to the maintenance of green wealth of your locality? Make a list of actions to be taken by you.

Answer :

I can take care of the green cover of my locality by growing plants in my locality. I shall motivate the people of my neighbourhood to plant more trees and take care of the existing trees by creating awareness about the importance of plant life in an ecosystem.

In order to execute this plan, I would initiate the proceedings and organize weekly events trees and plants. Creating awareness among the children and youth would be of top priority as they will easily understand the issues that we are facing.

Planting new trees is, as important as looking after the existing ones. So, my volunteers and I would water the plants and trees on a regular basis and will also take care of their nutrient requirements using organic manure and by letting the soil to replenish its valuable nutrients.

Q.8 Explain how deforestation leads to reduced rainfall

Answer :

Deforestation means cutting down of trees or forests.

Trees give out a huge amount of water in the form of water vapour during transpiration. Trees transpire and play an important role in the water cycle as it adds moisture to the air which brings rainfall.

Deforestation will lead to the reduction of water vapour and this affects cloud formation and thus it results in less rainfall. As a result of less rainfall, soil will be dry and this leads to lower water intake in the trees thus interrupting the water cycle process and reducing rainfall.

Q.9 Find out about national parks in your state. Identify and show their location on the outline map of India.

Answer :

National Parks in India is as follows

Q.10 Why should paper be saved? Prepare a list of ways by which you can save paper.

Answer :

There is a serious need to save paper because by saving paper we prevent the cutting down of a tree. This will also save water that is used in the manufacture of a paper. Moreover, there will be less consumption of the harmful chemicals used in papermaking, thus there will be least effects of chemicals on human beings and other organisms.

Different ways of saving paper are :

(a) Recycling of paper.

(b) Double sided printing to reduce paper consumption.

(c) Adopting online communications to reduce paper usage.

Q.11 Complete the world puzzle.

Down

1. Species on the verge of extinction.
2. A book carrying information about endangered species.
5. Consequence of deforestation.

across

1. Species which have vanished.
3. Species found only in a particular habitat.
4. Variety of plants, animals and microorganisms found in an area.

Answer :

Down

Endangered
Red Data Book
Deserts

Across

Extinct
Endemic
Biodiversity


EXPLANATION


(DOWN)

1. An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due habitat loss, poaching and invasive species etc.

2. Red Data Book is a state document established for documenting rare and endangered species of animals, plants, and fungi as well as some local subspecies that exist within the territory. The Red Data Book contains the complete list of threatened species.

5. Consequence of deforestation is desertification. It is a type of land degradation in drylands in which biological productivity is lost due to natural processes or induced by human activities whereby fertile areas become increasingly arid.


(ACROSS)

1. Extinction is the termination of a kind of organism or a kind of species. The moment of extinction is generally considered to be the death of the last individual of the species and the capacity to recover the breed is lost before extinction.

3. Endemic species are plant and animal species that are found in a particular geographical region and are found no-where else in the world. For example some species are endemic to a continent while the others can be endemic to an island.

4. Biodiversity is the biological variety and variability of life on Earth. It is typically a measure of variation at the genetic, species, and ecosystem level.