NCERT Exercise
1.
Choose the right answer from the four alternatives given below:
(i) To
which one of the following types of vegetation does rubber belong to?
(a)
Tundra (c) Himalayan
(b)
Tidal (d) Tropical Evergreen
Ans. (d)
Tropical Evergreen
(ii) Cinchona
trees are found in the areas of rainfall more than
(a) 100
cm (c) 70 cm
(b) 50
cm (d) less than 50 cm
Ans. (a) 100
cm
(iii)
In which of the following state is the Simlipal bio-reserve located?
(a)
Punjab (b) Delhi
(c)
Odisha (d) West Bengal
Ans. (c)
Odisha
(iv)
Which one of the following bio-reserves of India is not included in the world
network of bioreserve?
(a)
Manas (c) Gulf of Mannar
(b)
Nilgiri (d) Panna
Ans. (d) Panna
2.
Answer the following questions briefly.
(i)
What factors are responsible for the distribution of plants and animals in
India?
Ans. Natural vegetation refers to a plant community, which has
grown naturally without human aid and has been left undisturbed by humans for a
long time. This is termed as a virgin vegetation. Thus, cultivated crops and
fruits, orchards form part of vegetation but not natural vegetation.
The virgin
vegetation, which are purely Indian are known as endemic or indigenous species
but those which have come from outside India are termed as exotic plants.
Factors those are responsible
for the distribution of plants and animals in India are:
(a) Relief -
(i)
Land
(ii)
Soil
(iii)
Drainage (River)
(b) Climate
-
(iv)
Temperature
(v)
Photoperiod (Duration of Sunlight)
(vi)
Precipitation (Rainfall)
(ii)
What is a bio-reserve? Give two examples.
Ans. A vast areas reserved for the preservation and protection of
flora and fauna is called bio-reserves. Eighteen biosphere reserves (Sundarbans,
Simlipal, Gulf of Mannar,Dihang-Dibang, Nilgiri,Dibru Saikhowa, Nanda Devi,
Agasthyamalai, Nokrek, Kangchendzonga, Great Nicobar, Pachmarhi, Manas,
Achanakmar-Amarkantak, Kachchh, Cold Desert, Seshachalam and Panna) have been set up in the country to protect
flora and fauna. Ten out of these, the Sundarbans, Nanda Devi, the Gulf
of Mannar, the Nilgiri, Nokrek, Great Nicobar, Manas, Simlipal, Pachmarhi and
Achanakmar-Amarkantak have been included in the world network of biosphere
reserves. The Manas name is derived from the Manas River which
was named after the serpent Goddess Manasa. This is famous for the population
of wild water buffalo.
(iii)
Name two animals having habitat in tropical and montane type of vegetation.
Ans. Tropical
Evergreen Forests - These forests are found in more than 200 cm rainfall areas. The
common animals found in these forests are elephant, monkey, lemur and deer. One
horned rhinoceroses are found in the jungles of Assam and West Bengal. Besides
these animals, plenty of birds, bats, sloth, scorpions and snails are also
found in these jungles.
Montane
Forests - In mountainous areas, the decrease in temperature with
increasing altitude leads to the corresponding change in natural vegetation.
The
common animals found in these forests are Kashmir stag, spotted dear, wild
sheep, jack rabbit, Tibetan antelope, yak, snow leopard, squirrels, Shaggy horn
wild ibex, bear and rare red panda, sheep and goats with thick hair.
3.
Distinguish between
(i)
Flora and Fauna
Ans. The term flora is used to denote plants
of a particular region or period. Similarly, the species of animals are
referred to as fauna.
(ii)
Tropical Evergreen and Deciduous forests
Ans. Tropical
Evergreen Forests - These forests are restricted to heavy rainfall (more than 200 cm)
areas of the Western Ghats and the island groups of Lakshadweep, Andaman and
Nicobar, upper parts of Assam and Tamil Nadu coast. The trees reach great
heights up to 60 metres (196.85 feet) or even above. Since the region is warm
and wet throughout the year, it has a luxuriant vegetation of all kinds —
trees, shrubs and creepers giving it a multilayered structure. There is no
definite time for trees to shed their leaves. As such, these forests appear
green all the year round. Some of the commercially important trees of this
forest are ebony, mahogany, rosewood, rubber and cinchona.
Deciduous
forests - These are the most widespread forests of India. They are
also called the monsoon forests and spread over the region receiving
rainfall between 200 cm and 70 cm. Trees of this forest type shed their
leaves for about six to eight weeks in dry summer.
On the
basis of the availability of water, these forests are further
divided into moist and dry deciduous.
(a)
The moist deciduous forests are
found in areas having rainfall between 200 cm and 100 cm. Teak is the most
dominant species of this forest. Bamboos, Sal, Shisham, Sandalwood, Khair, Kusum,
Arjun and Mulberry are other commercially important species.
(b)
The dry deciduous forests are
found in areas having rainfall between 100 cm and 70 cm. Teak, Sal, Peepal and Neem
are the most dominant species of this forest. A large part of these forests has
been cleared for cultivation and some parts are used for grazing.
4. Name
different types of Vegetation found in India and describe the vegetation of
high altitudes.
Ans. Our
country India is one of the 12 mega bio-diversity countries of the world. With
about 47,000 plant species India occupies tenth place in the world and fourth
in Asia in plant diversity.
The
following major types of vegetation may be identified in our country:
(i) Tropical Evergreen Forests
(ii) Tropical Deciduous Forests
(iii) Tropical Thorn Forests and Scrubs
(iv) Montane Forests
(v) Mangrove Forests
Montane
Forests - the vegetation of high altitudes
In
mountainous areas, the decrease in temperature with increasing altitude leads
to the corresponding change in natural vegetation. As such, there is a
succession of natural vegetation belts in the same order as we see from the
tropical to the tundra region.
(a)
The wet temperate types of forests are found between a height of
1000 and 2000 metres. Evergreen broad-leaf trees, such as oaks and chestnuts
predominate.
(b)
Between 1500 and 3000 metres, temperate forests containing
coniferous trees, like pine, deodar, silver fir, spruce and cedar, are found.
These forests cover mostly the southern slopes of the Himalayas, places having
high altitude in southern and north-east India. At higher elevations, temperate
grasslands are common.
(c)
At high altitudes, generally, more than 3,600 metres above the
sea level, temperate forests and grasslands give way to the Alpine vegetation.
Silver fir, junipers, pines and birches are the common trees of these forests. However,
they get progressively stunted as they approach the snow-line. Ultimately,
through shrubs and scrubs, they merge into the Alpine grasslands. These are
used extensively for grazing by nomadic tribes, like the Gujjars and the
Bakarwals.
(d)
At higher altitudes, mosses and lichens form part of tundra
vegetation.
5.
Quite a few species of plants and animals are endangered in India. Why?
Ans. Due to
excessive exploitation of plant and animal resources by human beings, the
ecosystem has been disturbed. About 1,300 plant species are endangered and 20
species are extinct. The World Conservation Union’s Red List has named 352
medicinal plants of which 52 are critically threatened and 49 endangered.
The
main causes for this major threat to nature are hunting by greedy hunters for
commercial purposes. Pollution due to chemical and industrial waste, acid
deposits, introduction of alien species and reckless cutting of the forests to
bring land under cultivation and habitation, are also responsible for the
imbalance.
6. Why
has India a rich heritage of flora and fauna?