Class 7 Science Notes for Forest Our Life Line

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CLASS 7
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FOREST OUR LIFE LINE
Deforestation
Clearing of forests and trees eventually using that land for other purposes like agriculture and
other human activities. The main causes for deforestation are:
(i) agricultural expansion
(ii) livestock grazing
(iii) Illegal logging, which is cutting, processing of trees in prohibited land.
(iv) human infrastructure expansion
(v) overpopulation

Consequences of Deforestation
(i) The source of conversion of carbon dioxide to oxygen is reduced. Plants use photosynthesis to
convert carbon dioxide to oxygen. This process leads to Global Warming.
(ii) Pollution increases as there is a decrease of plants, which give out fresh air to breathe.
(ii) Ground water level also gets lowered. Desertification and droughts are the results of
deforestation.
Wildlife Conservation
Conservation of forest and wildlife
 Many NGO’s are working towards creating public awareness for conserving depleting
forest cover and vanishing wildlife.
 Central and state governments in India have set up national parks and wildlife sanctuaries
to protect forests and endangered species in wildlife.
Species
Species is a group of populations, which are capable of interbreeding (reproducing fertile
offspring).
Flora and fauna
The plants and animals observed in a specific region are referred to as flora and fauna of that
region.
Biosphere Reserves
Biosphere and Biodiversity
 Biosphere is that part of the earth in which living organisms exist and is a sum of all the
ecosystems.
 Biodiversity, refers to the variety of organisms existing on the earth, their
interrelationships and their relationship with the environment.
Endemic species
Endemic species are species of plants and animals that are exclusively found only in a particular
region or area.

Wildlife Conservation Projects
(i) Biosphere Reserve- Large areas which conserve biodiversity and civilization of that region.
They preserve and protect tribal groups in addition to wildlife. Eg: Pachmarhi Biosphere
Reserve.
(ii) Zoo- Wild animals are kept for research, preservation and also for public exhibition and
tourism. Eg: Mysore zoo, Indira Gandhi zoological park.
(iii) National Park- Reserved habitats for both flora and fauna especially endangered species.
National parks cover large areas where animals can freely move around. E.g. Gir forest national
park, Periyar national park.
(iv) Sanctuary- Sanctuaries are largely protected habitats for animals. E.g. Krishna wildlife
sanctuary.
Recycling of Paper
Paper is recycled so that more trees do not have to be cut down to create more paper. It is
important that we conserve trees and reduce the use of paper as much as possible.
Reforestation
Reforestation is restoring of the cleared or destroyed forests by planting new trees.
Extinction
 Extinction is the dying out or death of all members of a species.
 Human intervention (either directly or indirectly) has become the leading cause of species
extinction.
 Eg: Animals like the Dodo bird, Tasmanian wolf are extinct.
Endangered animals
Animals whose count is reducing to an extent that they might face extinction are known as the
endangered animals. Eg: Giant panda, tiger. Red Data Book is a source (reference) book, keeping
a record of all the plant and animals that are endangered.
Ecosystem
Ecosystem is the region consisting of all the living plants, animals and microorganisms in an area
along with non-living components such as climate, soil, river deltas, etc.
Migration
Migration is defined as the movement of organisms in large numbers from one place to another.

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