Case Study Based Questions: Conservation of Plants and Animals | Science Class 8 PDF Download

Case Study 1

A great variety of plants and animals exist on earth. They are essential for the well-being and survival of mankind. Today, a major threat to survival of these organisms is deforestation. We know that deforestation means clearing of forests and using that land for other purposes. Trees in the forest are cut for some of the purposes mentioned below:

• Procuring land for cultivation.
• Building houses and factories.
• Making furniture or using wood as fuel.

Some natural causes of deforestation are forest fires and severe droughts. Deforestation increases the temperature and pollution level on the earth. It increases the level of carbon dioxide in the atmosphere. Ground water level also gets lowered. They know that deforestation disturbs the balance in nature. They were told by Professor Ahmad that if cutting of trees continues, rainfall and the fertility of the soil will decrease. Moreover, there will be increased chances of natural calamities such as floods and droughts. Recall that plants need carbon dioxide for photosynthesis. Fewer trees would mean that less carbon dioxide will be used up resulting in its increased amount in the atmosphere. This will lead to global warming as carbon dioxide traps the heat rays reflected by the earth. The increase in temperature on the earth disturbs the water cycle and may reduce rainfall. This could cause droughts. Deforestation is a major cause which leads to the change in soil properties. Physical properties of the soil get affected by plantation and vegetation. Recall from Class VII how trees prevent soil erosion. Fewer trees result in more soil erosion. Removal of the top layer of the soil exposes the lower, hard and rocky layers. This soil has less humus and is less fertile. Gradually the fertile land gets converted into deserts. It is called desertification. Deforestation also leads to a decrease in the water holding capacity of the soil. The movement of water from the soil surface into the ground (infiltration rate) is reduced. So, there are floods. The other properties of the soil like nutrient content, texture etc., also change because of deforestation.

Q1: Which among the following are some of the natural causes of deforestation?
(a) Reusing
(b) Recycling
(c) Plantation
(d) Forest fires
Ans: (d)

Q2: Due to the process of soil erosion, fertile land gradually gets converted into deserts. This process is called:
(a) Desertification
(b) Extinction
(c) Eradication
(d) Denitrification
Ans: (a)

Q3: Water holding capacity of soil ………………………… due to deforestation.
(a) Increases
(b) Decreases
(c) Remains the same
(d) None of the above
Ans: (b)

Q4: What are the effects of deforestation on the environment?
Ans: Deforestation increases the temperature and carbon dioxide levels in the atmosphere, decreases the groundwater level, reduces rainfall, and lowers the fertility of the soil. It also causes desertification and decreases the water holding capacity of the soil.

Q5: Mention a few reasons for the cutting of trees in forests.
Ans: Trees are cut to procure land for cultivation, to build houses and factories, to make furniture, and to use as fuel.

Case Study 2

Biosphere is that part of the earth in which living organisms exist or which supports life. Biological diversity or biodiversity, refers to the variety of organisms existing on the earth, their inter relationships and their relationship with the environment. To protect our flora and fauna and their habitats, protected areas called wildlife sanctuaries, national parks and biosphere reserves have bee near marked. Plantation, cultivation, grazing, felling trees, hunting and poaching are prohibited there. Wildlife Sanctuary: Areas where animals are protected from any disturbance to them and their habitat. National Park: Areas reserved for wild life where they can freely use the habitats and natural resources. Biosphere Reserve: Large areas of protected land for conservation of wildlife, plant and animal resources and traditional life of the tribals living in the area. Children along with Professor Ahmadand Madhavji enter the biosphe rereserve area. Madhavji explains that biosphere reserves are the areas meant for conservation of biodiversity. As you are aware that biodiversity is the variety of plants, animals and microorganisms generally found in an area. The biosphere reserves help to maintain the biodiversity and culture of that area. A biosphere reserve may also contain other protected areas in it. The Pachmarhi Biosphere Reserve consists of one national park named Satpura and two wildlife sanctuaries named Bori and Pachmarhi. As the children walk around the biosphere reserve, they appreciate the green wealth of the forest. They are very happy to see tall teak trees and animals inside the forest. Suddenly, Paheli finds a rabbit and wants to catch it. She starts running after it. Professor Ahmad stops her. He explains that animals are comfortable and happy in their own habitat. We should not disturb them. Madhavji explains that some animals and plants typically belong to a particular area. The plants and animals found in a particular area are termed flora and fauna respectively of that area.

Q1: Biosphere reserves help to maintain the ……………….. and culture of that area.
(a) Literacy
(b) Population
(c) Pollution
(d) Biodiversity
Ans: (d)

Q2: The terms used to describe the plants and animals found in a particular area are:
(a) Flip and flop
(b) Flora and fauna
(c) Fight and flight
(d) Flower and Fish
Ans: (b)

Q3: Which of the following national parks is present in the Pachmarhi Biosphere Reserve?
(a) Satpura
(b) Jim Corbett
(c) Bandipur
(d) Kaziranga
Ans: (a)

Q4: Define Wildlife Sanctuary.
Ans: Wildlife Sanctuaries are areas where animals are protected from any disturbance to them and their habitat.

Q5: What is the definition of the term Biodiversity or Biological Diversity?
Ans: Biodiversity or Biological Diversity refers to the variety of organisms existing on earth, their interrelationships, and their relationship with the environment.

Case Study 3

Soon the group quietly enters the deep forest. Children are surprised to see a very big squirrel. This squirrel has a big fluffy tail. Madhavji tells them that this is known as the giant squirrel and is endemic to this area. Endemic species are those species of plants and animals which are found exclusively in a particular area. They are not naturally found anywhere else. A particular type of animal or plant maybe endemic to a zone, a state or a country. Madhavji shows sal and wild mango as two examples of the endemic flora of the Pachmarhi Biosphere Reserve. Bison, Indian giant squirrel and flying squirrel are endemic fauna of this area. Professor Ahmad explains that the destruction of their habitat, increasing population and introduction of new species may affect the natural habitat of endemic species and endanger their existence. Species is a group of population which are capable of interbreeding. This means that the members of a species can reproduce fertile offspring only with the members of their own species and not with members of other species. Members of a species have common characteristics. Professor Ahmad explains that killing (poaching) or capturing animals in general is strictly prohibited and punishable by law in all such places. Wildlife Sanctuaries like reserve forests provide protection and suitable living conditions to wild animals. He also tells them that people living in wildlife sanctuaries are allowed to do certain activities such as grazing by their livestock, collecting medicinal plants, firewood, etc. It is a pity that even protected forests are not safe because people living in the neighbourhood encroach upon them and destroy them. They recall that zoos are also places where animals receive protection. Some of the threatened wild animals like black buck, white eyed buck, elephant, golden cat, pink headed duck, gharial, marsh crocodile, python, rhinoceros, etc., are protected and preserved in our wild life sanctuaries. Indian sanctuaries have unique landscapes—broad level forests, mountain forests and bush lands in deltas of big rivers. On the roadside there was another board on which was written ‘Satpura National Park’. Children are now eager to go there. Madhavji tells them that these reserves are large and diverse enough to protect whole sets of ecosystems. They preserve flora, fauna, landscape and historic objects of an area. Satpura National Park is the first Reserve Forest of India. The finest Indian teak is found in thisforest. There are more than one hundred National Parks in India. As children move ahead, they see aboard with ‘Satpura Tiger Reserve’ written on it. Madhavji explains that Project Tiger was launched by the government to protect the tigers in the country. The objective of this project was to ensure the survival and maintenance of the tiger population in the country. Tiger is one of the many species which are slowly disappearing from our forests. But, the Satpura Tiger Reserve is unique in the sense that a significant increase in the population of tigers has been seen here. Once upon a time, animals like lions, elephants, wild buffaloes and barasingha were also found in the Satpura National Park. Animals whose numbers are diminishing to a level that they might face extinction are known as the endangered animals. Boojho is reminded of the dinosaurs which became extinct a long time ago. Survival of some animals has become difficult because of disturbances in their natural habitat. Professor Ahmad tells them that in order to protect plants and animals’ strict rules are imposed in all National Parks. Human activities such as grazing, poaching, hunting, capturing of animals or collection of firewood, medicinal plants, etc. are not allowed. Small animals are much more in danger of becoming extinct than the bigger animals. At times, we kill snakes, frogs, lizards, bats and owls ruthlessly without realising their importance in the ecosystem. By killing them we are harming ourselves. They might be small in size but their role in the ecosystem cannot be ignored. They form part of food chains and food webs. An ecosystem is made of all the plants, animals and microorganisms in an area along with non-living components such as climate, soil, river deltas etc.

Q1: Which among the following National Park is the first reserve forest of India?
(a) Omkareshwar National Park
(b) Satpura National Park
(c) Bison National Park
(d) Chandoli National Park
Ans: (b)

Q2: ………………………… are the animals whose numbers are diminishing to a level that they might face extinction.
(a) Endangered animals
(b) Endemic species
(c) Pandemic species
(d) Excessive animals
Ans: (a)

Q3: Which of the following is a threatened wild animal that is protected and preserved in our wildlife sanctuaries?
(a) Black buck
(b) Grey wolf
(c) Panda
(d) Lion-tailed macaque
Ans: (a)

Q4: Define the concept of species.
Ans: A species is a group of populations that is capable of interbreeding. The members of a species can reproduce fertile offspring only with the members of their species.

Q5: What do you understand by the term “endemic species”?
Ans: Endemic species are those species of plants and animals that are found exclusively in a particular area. They are not naturally found anywhere else.

Case Study 4

Professor Ahmad explains about Red Data Book to the children. He tells them that Red Data Book is the source book which keeps a record of all the endangered animals and plants. Red Data Book is maintained internationally by an organisation. India also maintains Red Data Book for plants and animals found in India. The excursion party then enters deeper into the forest under the guidance of Madhavji. They sit near the Tawa Reservoir to relax for some time. Paheli observes some of the birds near the river. Madhavji tells the children that these are migratory birds. These birds have flown here from other parts of the world. Migratory birds fly to far away areas every year during a particular time because of climatic changes. They fly for laying eggs as the weather in their natural habitat becomes very cold and inhospitable. Birds who cover long distances to reach another land are known as migratory birds. Professor Ahmad draws attention of the children to another cause of deforestation. He tells them that it takes 17 full grown trees to make one tonne of paper. Therefore, we should save paper. Professor Ahmad also tells that paper can be recycled five to seven times for use. If each student saves at least one sheet of paper in a day, we can save many trees in a year. We should save, reuse used paper and recycle it. By this we not only save trees but also save energy and water needed for manufacturing paper. Moreover, the amount of harmful chemicals used in paper making will also be reduced. Professor Ahmad suggests that the answer to deforestation is reforestation. Reforestation is restocking of the destroyed forests by planting new trees. The planted trees should generally be of the same species which were found in that forest. We should plant at least as many trees as we cut. Reforestation can take place naturally also. If the deforested area is left undisturbed, it re- establishes itself. In natural reforestation there is no role of human beings. We have already caused tremendous damage to our forests. If we have to retain our green wealth for future generations, plantation of more trees is the only option. Professor Ahmad told them that in India we have the Forest (Conservation) Act. This act is aimed at preservation and conservation of natural forests and meeting the basic needs of the people living in or near the forests. After some rest Madhavji asks the children to start heading back because it is not advisable to stay in the jungle after sunset. On getting back, Professor Ahmad and the children thank Madhavji for guiding them through this exciting experience.

Q1: Birds who cover long distances to reach another land are known as ……………………………. birds.
(a) Flying
(b) Endemic
(c) Statutory
(d) Migratory
Ans: (d)

Q2: In India, which act is aimed at the preservation and conservation of natural forests and meeting the basic needs of the people living in or near the forests?
(a) RTE Act
(b) Forest Act
(c) Environment Act
(d) Air Act
Ans: (b)

Q3: Which of the following is the best measure to save paper?
(a) Recycling paper
(b) Excessive use
(c) Wasting paper
(d) Tearing paper
Ans: (a)

Q4: Define “Reforestation”.
Ans: Restocking of destroyed forests by planting new trees, which are generally of the same species that were found in the forest, is called reforestation.

Q5: What is a “red data book”?
Ans: A “red data book” is a public document created for recording endangered and rare species of animals, plants, and fungi, as well as some local subspecies that exist within a particular region. The purpose of the red data book is to provide comprehensive information on the conservation status of these species and to raise awareness about their risk of extinction.