Conservation of Plants and Animals (Chapter
5 Class 8 Science)
To maintain the balance of nature, it is important to conserve plants and
animals. This involves protecting forests (plants) and wildlife (animals),
understanding the impact of human activities like deforestation, and taking
steps such as creating protected areas and reforestation.
Biodiversity and the Biosphere
Biodiversity: The variety of living organisms (plants, animals,
microorganisms) in a given area, including their interrelationships and
interaction with the environment[1]. High biodiversity keeps
ecosystems stable and healthy. Conserving biodiversity ensures
natural balance, as different species depend on each other for survival.
Biosphere: The part of the Earth in which living organisms exist or
that supports life[1]. It includes all ecosystems – from forests and
oceans to deserts and mountains – essentially the global sum of all
habitats where life is possible.
Deforestation and Its Causes
Deforestation means the clearing or cutting down of forests, usually to use
the land for other purposes[2]. Trees are removed and not replanted, which
reduces forest cover. Major causes of deforestation include:
Agriculture Expansion: Clearing land for cultivation of crops and for
cattle grazing to feed a growing population[3]. Forests are often cut
down to create farms or pastures.
Urbanization & Development: Cutting trees to build houses, roads,
and factories. Procuring land for building infrastructure and
settlements results in loss of forest area[3].
Logging & Wood Use: Felling trees for timber to make furniture, for
wood as fuel, and for paper manufacturing[3]. Wood-based industries
increase demand for cutting forests.
Natural Causes: Sometimes forests are lost due to natural events like
forest fires or severe droughts (which can kill trees)[4]. These events
can clear large areas of forest if they occur frequently.
(Activity 5.1: Make a list of causes of deforestation and classify them into
natural causes vs. man-made causes.)
, Consequences of Deforestation
Deforestation leads to a number of harmful effects on the environment and
living beings:
Climate Change: With fewer trees, the level of carbon dioxide (CO₂)
in the atmosphere increases (as less CO₂ is absorbed by plants). This
contributes to global warming because CO₂ traps heat on Earth[5]. As a
result, the overall temperature rises and weather patterns change.
Disturbed Rainfall & Water Cycle: Trees release water vapor into
the air (transpiration), which helps in cloud formation. Fewer trees
means less rainfall. Deforestation can thus reduce rainfall, leading to
droughts, while at the same time the lack of vegetation can cause
floods due to faster rain runoff[6][7]. In summary, cutting forests may
reduce rainfall on one hand and increase flood risk on the other.
Soil Erosion and Desertification: Tree roots bind soil. Without trees,
topsoil gets eroded by wind and water[8]. The top fertile layer is lost,
exposing hard, rocky soil that has less humus. This loss of fertility can
turn once-green areas into deserts – a process called
desertification[9].
Lower Groundwater Levels: With reduced rainfall and fewer roots to
facilitate water infiltration, less water seeps into the ground.
Groundwater levels drop, meaning wells and springs may dry up over
time[10].
Loss of Biodiversity: Forests are habitats for numerous species.
When trees are removed, many plants and animals lose shelter and
food. Deforestation can lead to species becoming endangered or
even extinct due to habitat loss. It disturbs the natural balance in
ecosystems, as the food chains and life cycles of organisms are
disrupted[10].
Increased Pollution: Fewer forests also mean less natural filtration of
air and water. The air may have higher pollution (more CO₂, dust,
smoke) without trees to clean it.
(Activity 5.2: Discuss how deforestation might affect animal life – e.g. loss of
habitat, increased human-wildlife conflict, etc.)
Conservation of Forests and Wildlife
Given the serious consequences of deforestation, conservation of plants
and animals is crucial. The government and communities have taken steps
to protect our natural heritage:
Protected Areas: Certain regions are designated as protected areas
for wildlife and forest conservation[11]. These include Wildlife
Sanctuaries, National Parks, and Biosphere Reserves. In
protected areas, activities like hunting, poaching (illegal killing of
5 Class 8 Science)
To maintain the balance of nature, it is important to conserve plants and
animals. This involves protecting forests (plants) and wildlife (animals),
understanding the impact of human activities like deforestation, and taking
steps such as creating protected areas and reforestation.
Biodiversity and the Biosphere
Biodiversity: The variety of living organisms (plants, animals,
microorganisms) in a given area, including their interrelationships and
interaction with the environment[1]. High biodiversity keeps
ecosystems stable and healthy. Conserving biodiversity ensures
natural balance, as different species depend on each other for survival.
Biosphere: The part of the Earth in which living organisms exist or
that supports life[1]. It includes all ecosystems – from forests and
oceans to deserts and mountains – essentially the global sum of all
habitats where life is possible.
Deforestation and Its Causes
Deforestation means the clearing or cutting down of forests, usually to use
the land for other purposes[2]. Trees are removed and not replanted, which
reduces forest cover. Major causes of deforestation include:
Agriculture Expansion: Clearing land for cultivation of crops and for
cattle grazing to feed a growing population[3]. Forests are often cut
down to create farms or pastures.
Urbanization & Development: Cutting trees to build houses, roads,
and factories. Procuring land for building infrastructure and
settlements results in loss of forest area[3].
Logging & Wood Use: Felling trees for timber to make furniture, for
wood as fuel, and for paper manufacturing[3]. Wood-based industries
increase demand for cutting forests.
Natural Causes: Sometimes forests are lost due to natural events like
forest fires or severe droughts (which can kill trees)[4]. These events
can clear large areas of forest if they occur frequently.
(Activity 5.1: Make a list of causes of deforestation and classify them into
natural causes vs. man-made causes.)
, Consequences of Deforestation
Deforestation leads to a number of harmful effects on the environment and
living beings:
Climate Change: With fewer trees, the level of carbon dioxide (CO₂)
in the atmosphere increases (as less CO₂ is absorbed by plants). This
contributes to global warming because CO₂ traps heat on Earth[5]. As a
result, the overall temperature rises and weather patterns change.
Disturbed Rainfall & Water Cycle: Trees release water vapor into
the air (transpiration), which helps in cloud formation. Fewer trees
means less rainfall. Deforestation can thus reduce rainfall, leading to
droughts, while at the same time the lack of vegetation can cause
floods due to faster rain runoff[6][7]. In summary, cutting forests may
reduce rainfall on one hand and increase flood risk on the other.
Soil Erosion and Desertification: Tree roots bind soil. Without trees,
topsoil gets eroded by wind and water[8]. The top fertile layer is lost,
exposing hard, rocky soil that has less humus. This loss of fertility can
turn once-green areas into deserts – a process called
desertification[9].
Lower Groundwater Levels: With reduced rainfall and fewer roots to
facilitate water infiltration, less water seeps into the ground.
Groundwater levels drop, meaning wells and springs may dry up over
time[10].
Loss of Biodiversity: Forests are habitats for numerous species.
When trees are removed, many plants and animals lose shelter and
food. Deforestation can lead to species becoming endangered or
even extinct due to habitat loss. It disturbs the natural balance in
ecosystems, as the food chains and life cycles of organisms are
disrupted[10].
Increased Pollution: Fewer forests also mean less natural filtration of
air and water. The air may have higher pollution (more CO₂, dust,
smoke) without trees to clean it.
(Activity 5.2: Discuss how deforestation might affect animal life – e.g. loss of
habitat, increased human-wildlife conflict, etc.)
Conservation of Forests and Wildlife
Given the serious consequences of deforestation, conservation of plants
and animals is crucial. The government and communities have taken steps
to protect our natural heritage:
Protected Areas: Certain regions are designated as protected areas
for wildlife and forest conservation[11]. These include Wildlife
Sanctuaries, National Parks, and Biosphere Reserves. In
protected areas, activities like hunting, poaching (illegal killing of
