CBSE Class 8 Science Conservation of Plants and Animals Chapter 5 Conservation Of Plants: Deforestation And Its Causes
A forest is a large area covered with trees and plants. It provides habitat for various plants and animals. The process of clearing away forests by cutting them down or burning them is called deforestation. Various causes that lead to deforestation are
- Procuring land for cultivation, Forest trees are cut down to obtain more agricultural land for the cultivation of crops to feed the increasing population.
- Building houses and factories. The trees are cut down to build homes, factories, roads, dams, etc.
- Making various products Paper or wood for making doors, windows, etc., is obtained from trees.
- Natural causes Forest fires, severe droughts, etc., also lead to deforestation.
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Consequences Of Deforestation
Deforestation harms the environment and various living organisms. Some major consequences discussed here are
1. Global Warming
Green plants use carbon dioxide for photosynthesis (preparation of food). When fewer trees are left due to deforestation, less carbon dioxide is absorbed, resulting in its increased amount in the atmosphere.
Carbon dioxide gas traps heat rays reflected by the surface of the Earth. Trapping of heat rays by carbon dioxide increases the temperature of Earth’s atmosphere, thus leading to global warming.
2. Disturbance In the Water Cycle
The consequent increase in the temperature of Earth disturbs the water cycle. This leads to a decrease in rainfall that lowers the groundwater level and could cause droughts.
3. Soil Erosion And Desertification
Roots of trees bind the particles of topsoil, preventing them from being carried away by wind and water. When the forest trees are cut, there are no roots, and the bare topsoil becomes loose quickly and erodes rapidly. This results in soil erosion.
Removal of topsoil exposes the lower layer, which is hard, rocky, and has less humus and is less fertile. Other properties like nutrient content, texture, etc. of the soil also change. Over time, continued soil erosion can thus convert the land into a desert. This is called desertification.
4. Floods
The roots of forest trees help in absorbing the rainwater and allow it to percolate into the ground. Due to deforestation, there is a decrease in the water-holding capacity of the soil. The movement of water from the soil surface into the ground (in filtration rate) is reduced. This results in floods (excess water overflowing from the banks of the river into the adjoining areas).
5. Shortage Of Wood And Other Forest Products
Deforestation will lead to a shortage of wood used for various purposes. Also, there will be a lack of other forest products such as honey, gum, lac, etc., if cutting down forest trees continues
Deforestation Causes And Effects Class 8 Science Notes: Conservation Of Forest And Wildlife
Now we know that deforestation leads to many harmful effects on the environment, so it is important to conserve the forests and wildlife present in them.
This can be accomplished by protecting specific areas, where plantation, cultivation, grazing, felling trees, hunting, and poaching are prohibited.
Such areas are marked by the government as protected areas. The government lays down rules, methods, and policies to protect and conserve these areas.
The three main types of protected areas are as follows
- Biosphere reserves
- Wildlife sanctuaries
- National parks
Red Data Book explanation for Class 8 CBSE Science Biosphere Reserve
It is a large protected area of land meant for the conservation of wildlife, biodiversity, and the traditional lifestyle of the tribal people living in the area.
A biosphere reserve may also contain other protected areas within it, for example. The Pachmarhi biosphere reserve consists of one National park named Satpura and two wildlife sanctuaries, i.e., Bori and Pachmarhi.
The biodiversity found in the Pachmarhi biosphere reserve is similar to that of the upper Himalayan peaks and to those belonging to the lower Western Ghats.
Great Nicobar Biosphere Reserve and the Tiger Reserve are some examples of biosphere reserves located in India.
Afforestation Methods And Benefits Class 8 Science Notes Flora And Fauna
Some animals and plants typically belong to a particular area and are known as flora and fauna, respectively, of that area.
These are found naturally in that area, for example, cheetah, wolf, leopard, chinkara, blue bull, barking deer, and wild dog are examples of fauna of the Pachmarhi biosphere reserve. Teak, jamun, sal, mango, silver fern, and arjun are the flora of the Pachmarhi biosphere reserve.
Endemic Species
Endemic species are the species of plants and animals that are found exclusively in a particular area. They are not naturally found anywhere else. Examples: Sal and wild mango are examples of endemic flora of the Pachmarhi biosphere reserve. Bison, Indian giant squirrel, and flying squirrel are endemic fauna of this area.
The endemic species may vanish soon due to some factors, such as the destruction of their habitat, increasing population, introduction of new species, etc. Such factors affect the natural habitat of endemic species and endanger their existence.
Species
It is a group of population that is capable of interbreeding. This means that the members of a species can reproduce fertile offspring (one which can reproduce its kind) only with the members of their species and not with members of other species. Members ofa species have common characteristics.
Ecosystem And Its Components Class 8 CBSE Notes Wildlife Sanctuary
A wildlife sanctuary is a protected area for animals in their natural environment, like forests. There is no disturbance to animals and their habitat. Killing (poaching) and capturing ofwild animals is strictly prohibited and punishable by the law. It provides protection and suitable living conditions to wild animals.
Bharatpur wildlife sanctuary (Rajasthan) and Lockchao wildlife sanctuary (Manipur) are some examples of wildlife sanctuaries located in India.
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 wildlife sanctuaries. Indian sanctuaries have unique landscapes, i.e., broad level forests, mountain forests, and bush lands in deltas of big rivers.
Zoo
Zoos or zoological parks are large areas where many types of wild animals and birds brought from different parts of the world are kept in cages or enclosures, so that people can see them.
Though zoos and wildlife sanctuaries both protect wild animals, they are different from each other. Differences between the two are given below
CBSE Class 8 Biology Notes On Conservation Of Plants And Animals National Park
A national park is an area reserved for wildlife where they can freely use the habitats and natural resources.
It is a relatively large protected area and is maintained by the government to preserve flora and fauna, landscape, and historic objects of the area. These areas are diverse enough to protect whole sets of ecosystems.
National parks also provide human recreation and enjoyment. People are allowed to enter these areas, but exploitation of natural resources is strictly prohibited.
Satpura National Park
The first reserve forest of India is Satpura National Park in Madhya Pradesh. The finest Indian teak is found in this forest. The evidence of prehistoric human life in the I jungles, called rock shelters, is also found inside the I Satpura National Park, which gives us an idea of the life of primitive people.
Also, many rock paintings are found in these shelters, and the figures of animals and men fighting, hunting, dancing, and playing musical instruments are depicted in these paintings. Many tribals still live in this area. A total of 55 rock shelters have been identified in Pachmarhi Biosphere Reserve
Project Tiger
Project Tiger is a wildlife conservation project that was launched by the Government of India to protect tigers in the country. The objective of this project was to ensure the survival and maintenance of the tiger population in the country. There is a ‘Satpura Tiger Reserve’ in the Satpura National Park, which is a part of Project Tiger.
Tigers are one of the many species that 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 barasingha, wild buffalo, lions, and elephants were also found in the Satpura National Park. All these animals have now vanished from this area due to the illegal activities of people living in nearby areas
Endangered Animals and Extinct Animals The species that no longer exist anywhere on Earth are called extinct animals. These have died out completely. A species becomes extinct when the last living member of that species dies. For example. dinosaurs.
Animals whose numbers are diminishing to a level that they might face extinction shortly are called endangered animals. These are on the verge of vanishing from the Earth, and if appropriate actions to save them are not taken, they may become extinct.
The 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. They might be small in size, but their role in the ecosystem cannot be ignored.
Hence, we are indirectly harming ourselves by killing them. These small animals form parts of food chains and food webs, which are essential for maintaining balance in nature. For instance, when the snake is killed for its skin. It disrupts the food chain by leading to an increase in the population of pests such as mice, which in turn can cause damage to crops.
Note: An ecosystem is made up of all the plants, animals, and microorganisms in an area, along with non-living components such as climate, soil, rivers, deltas, etc
Red Data Book
- A Red Data Book contains a list of species whose continued existence is threatened, i.e., endangered animals and plants.
- Red Data Book is maintained internationally by an organisation known as the International Union for Conservation of Nature (IUCN). India also maintains the Red Data Book for plants and animals found in India.
Ecosystem And Its Components Class 8 CBSE Notes Migration
The phenomenon of the movement of animals (or birds) to move from one place to another based on season is called migration.
It is an adaptation to escape the harsh and cold conditions of their normal habitat, to survive, and reproduce. Birds that cover long distances to reach another land are known as migratory birds.
Migratory birds fly to faraway areas every year during a particular time because of climate change. They fly to lay eggs as the weather in their natural habitat becomes very cold and inhospitable. For example, Siberian cranes, flamingoes, etc., that flock to India during the winter.
CBSE Class 8 Biology Notes On Conservation of Plants And Animals, Recycling Of Paper
Paper is made from wood pulp that is produced from the wood of forest trees. Therefore, it is one of the important products we get from the forests and thus, a major cause of deforestation. It is estimated that 17 full-grown trees are needed to make one ton of paper. So, we should save paper as much as possible.
We can save paper by filling every sheet of paper, by reusing and recycling paper (as paper can be recycled 5 to 7 times for use). ‘Recycling of paper’ means processing the waste paper to make new paper that can be used again. We should save, reuse, and recycle paper for the following reasons
- To save forest trees from being cut.
- To save the water used in paper making.
- To save the energy (electricity) used in making paper.
- To reduce the amount of harmful chemicals used in paper making
Migration Of Animals and Its Reasons Class 8 Science Notes Reforestation
Reforestation is known as the phenomenon of restocking the destroyed forests by planting new trees (generally of the same species that were cut). We should at least plant as many trees as have been cut down.
Reforestation can also take place naturally. If the deforested area is left undisturbed, it re-establishes itself. In natural reforestation, there is no role for human beings.
If we have to retain our green wealth, i.e., forests for future generations, the plantation of more trees is the only option.
In India, the Government has enacted the Forest Conservation Act (1980) to save forests. It aims at the presentation and conservation of natural resources, while meeting the basic needs of the people living in or near the forests at the same time.
Chipko Andolan was a 1970 environmental movement In India whore people hugged trees to prevent deforestation highlighting tho need for environmental conservation.
Biodiversity: Diversity of plants, animals, and microorganisms in a particular area.
Biosphere reserve Large protected area where plants and animals are protected along with natural resources.
Deforestation: Large-scale removal of trees from forests.
Desertification: Conversion of fertile land to desert due to deforestation.
Ecosystem: It consists of living and non-living components.
Endangered species are Species that are threatened and can become extinct if not conserved or protected.
Endemic species: Species of plants and animals that are found exclusively in a particular area.
Extinct Species: Those that no longer exist anywhere on Earth.
Flora: Plants present in an area:
Fauna: Animals living in an area.
Migratory birds: Are Birds that cover long distances to reach another land.
National park: Areas are reserved for wildlife where they can freely use the habitats and natural resources.
Reforestation: Restocking of destroyed forests by planting new trees.
Red Data Book: Official record of all endangered plants and animals.
Sanctuary: A Protected area for animals in their natural environment.