Transcript CHAPTER - 12 Forests : Our lifeline

CHAPTER - 17
Forests : Our lifeline
1) Forest :Forest is a natural habitat for many different kinds of
plants and animals. Forests provide food and shelter for
animals.
Some common animals found in a forest are :- lion, tiger,
elephant, monkey, deer, zebra, jackal, bison, boar, snake,
porcupine, crocodile etc.
Some common types of plants found in forests are :trees like teak, bamboo, fig, saal, sesham, semal, neem,
palash, khair, amla, kachnar etc. Forests also have several
kinds of shrubs, herbs and grasses, climbers, creepers
etc.
TEAK
SAL
BAMBOO
NEEM
FIG
SHEESHAM
AMLA
KACNAR
2) Products we get from forests :We get several useful products from forests like wood,
spices, gum, oils, honey, sealing wax, catechu, fodder for
animals, medicinal plants etc.
3) Characteristics of trees in forests :The branchy part of a tree above the stem is called the crown of the
tree. The crown of trees have different shapes.
Some crown shapes of trees
The branches of tall trees look like a roof over the other plants in the
forest. This is called a canopy.
Trees have different heights, crowns, shapes of leaves, flowers and
fruits.
4) Interdependence of components of forest :Forest has different types of plants and animals. They are
autotrophs, heterotrophs, saprotrophs and decomposers.
Autotrophs:- are green plants which prepare food by
photosynthesis.
Heterotrophs:- are animals which get their food directly or
indirectly from plants.
Saprotrophs:- are animals which feed on dead animals.
Decomposers:- are micro organisms which decompose
dead plants and animals into humus.
Food chain:- Organisms which feed on plants are eaten by
other organisms and so on to form food chains.
eaten by
eaten by
eaten by
eaten by
Eg : Grass
Insects
Frog
Snake
Eagle
There are many food chains in the forest. All food chains are linked
together. If any food chain is disturbed, it affects other food chains.
Every component of forest depends on one another. If we remove one
component like trees, all the other components are affected.
5) Balance of oxygen and carbon dioxide in the
atmosphere :During respiration plants and animals take in oxygen
and release carbon dioxde. During photosynthesis
plantstake in carbon dioxide and release oxygen. So
plants help to maintain the oxygen and carbon dioxide
balance in the atmosphere.
This is why forests are called green lungs.
Oxygen
Plants
Animals
Carbon dioxide
6) Importance of forests :i) Forest is a natural habitat for a large number of plants
and animals.
ii) Forest help in maintaining the oxygen and carbon
dioxide balance in the atmosphere.
iii) Forests help in bringing good rainfall.
iv) Forest help to protect soil from erosion.
v) Forest absorb rainwater and helps to maintain water
table.
vi) We get medicinal plants, timber and many other useful
products from forests.
vii) Many people live in forests and forest provide them
with food, water, shelter and medicines.