Chapter 6
Life on the Earth
for millions of years, our earth was a barren planet without
any life. The first form of life
appeared in the water bodies belonging to the flora world (plant kingdom). Gradually, the plant life gave way to another
form of life which is known as fauna (animal kingdom). The relationship between plant kingdom,
animal kingdom and human beings with their environment is known as
Ecosystem. The human beings, who first
appeared on the earth's surface, were called Homosapiens. As we know, the earth is the only planet in
the solar system where life exists. This
living zone is known as biosphere.
Biosphere is divided into two kingdoms namely, plant kingdom and animal
kingdom. They live together in complete
harmony. In this zone, living things and
non - living things are also dependent on each other for their existence. Plants prepare their own food with the help
of non - living things like sunlight, air and water. That is why they are known as food
factories. Plants provide food for the
animals to satisfy their basic needs.
Animals also provide soil nutrients (with the their remains), which are
helpful for the growth of plants. Human
beings are the most important part of the biosphere as they derive all their
basic needs dies from it. Human beings
consume both plant food as well as animal food.
It is the only form of life in the biosphere which has altered the
environment according to its own needs.
THE PLANT KINGDOM For studying the plant kingdom, we can study different
vegetation belts of the world.
Vegetation includes forests, grasslands, bushes and shrubs. They vary from place to place because of the
variation in climatic conditions. For
example, in the equatorial region, where the temperature and rainfall is high
throughout the year, trees are tall and dense.
This type of climatic condition helps in the growth of plant and animal
life. On the other hand, in the desert
areas, where temperature is high and rainfall is less, the plant and animal
life is limited, the vegetable belts of the world can be broadly be divided
into various groups on the basis of their location and climatic
conditions. These are Tropical Hardwood
Forests, Grasslands, Deserts and Temperate Softwood Forests, Plant kingdom 41
Tropical Hardwood Forests These forests are found in
tropical regions between 23% ° North to 23% South. On the basis on difference in climatic
conditions and vegetation, these forests can be divided into two groups: (0)
Equatorial / Tropical Evergreen Forests: These forests are found on both sides
of the equator between 10 "North and 10" South latitudes. The main areas are Zaire basin in Africa,
Amazon basin in South America and few islands in the south - east Asia. These areas receive heavy rainfall throughout
the year and the temperature remains very high.
These forests remain green throughout the year. The trees are very tall. Main trees found in these areas are ebony, rubber,
tropical hardwood forest mahogany, rosewood, etc. (ii) Tropical Deciduous Forests: These
forests thrive between 10 "North to 23% North and 10 ° South to 23%. South
latitudes. This forest belt receives moderate rainfall and the trees here shed
their leaves in the dry season. The trees are
The main areas where these forests are found are India, China, Eastern
Brazil, etc. Common trees in these areas are sal, teak, bamboo, etc. Grasslands
Grasslands are areas where the vegetation is dominated by grasses, grass like
plants and scattering of trees.
Grasslands are found in the areas of scanty rainfall with varying temperature
conditions. On the basis of climatic conditions, they can be divided into two
groups: (0) Tropical Grasslands: They are located between CAMP the equatorial
forests Tropic of Cancer and hot deserts
in both the hemispheres. These Egantor grasslands receive about Campos Top
Charicom 100 cm rainfall. The grasses of these regions are very rough, thick
and tall. Campos in Brazil a re typical
Tropical Grasslands example of these forests.
Sayans Janos Tropical Grande 42
Stegges parts of the continents. (1) Temperate Grasslands: These grasslands
are located in the temperate zone and in the interior These grasslands receive
V. about 25 to 75 cm rainfall. They
sometimes praires receive snowfall also.
The Pusat grasses of these regions are short and soft. They Trops of Cancer are known by different
equator names in different areas, for example, (North America), Pampas (South
America), Downs (Australia) and Veld (South Africa) Temperate Grasslands
Temperate Grasslands Prairies Tropig of CARAM.
Pampas Canterbury Grassland Deserts A vast area, which has less
vegetation due to very scanty rainfall, is commonly known as a desert. On the basis of difference in temperature,
deserts can be categorized into two groups, namely: (i) Hot Deserts: These are
mostly located on the western margins of the continents where temperature
remains very high throughout the year.
Some important hot Hot Desert deserts of the world are the Sahara desert
(Africa), the Thar desert (India) and the Atacama (S. America). Cactus, shrubs and bushes are the common
vegetations of this area. (1) Cold
Deserts: The cold deserts are mostly found around the polar regions where
temperature remains below freezing point for the major part of the year. The common vegetation is comprised of mosses,
lichens, etc. The main areas are
northern part of Siberia (Russia) and northern part of Canada. Cold Desert Temperate Softwood Forests
Another type of vegetation which is common in the continental interiors of high
latitudes as well 43
Senas M (11) Temperate Grasslands: These grasslands are
located in the temperate zone and in the interior parts of the continents,
These grasslands receive about 25 to 75 cm rainfall. They sometimes Pros receive snowfall also. The grasses of these regions Tropic of Cancer
are short and soft. They are known by
different equator names in different areas, for example, (North America),
Pampas Down -Pampas (South America), Downs (Australia) and Veld (South Canal
Temperate Grasslands Grassland Africa) Temperate Grasslands Prairies Tropical
Canicen. Deserts a vast area, which has
less vegetation due to very scanty rainfall, is commonly known as a
desert. On the basis of difference in
temperature, deserts can be categorized into two groups, namely: (i) Hot
Deserts: These are mostly located on the western margins of the continents
where temperature remains very high throughout the year. Some important hot deserts of the world are
the Sahara desert (Africa), the Hot Desert Thar desert (India) and the Atacama
(S. America). Cactus, shrubs and bushes
are the common vegetations of this area, (ii) Cold Deserts: The cold deserts
are mostly found around the polar regions where temperature remains below
freezing point for the major part of the year.
The common vegetation is comprised of mosses, lichens, etc. The main areas are northern part of Siberia
(Russia) and northern part of Canada.
Cold Desert Temperate Softwood Forests Another type of vegetation which
is common in the continental interiors of high latitudes as well
human beings. In the
wildlife community, a few species, like tigers, lions, etc. , are already facing the dange of
extinction. The pollution level in
different countries is rising alarmingly and there is a considerable rise as
high altitude areas of Asia, Europe, North America, South America and New
Zealand are known as Taiga. These are
also known as Coniferous forests because they are mainly cone - bearing trees
The trees are also conical in shape and have very soft wood. They have needle-shaped leaves. The coniferous forests are more uniform and
consist of pure stands of a few species.
The main trees are pine, fir, spruce, larch, etc. THE ANIMAL KINGDOM As mentioned earlier,
along with plants, animals also live in the biosphere. These can be birds, insects or animals. The animals vary from place to place because
of the variation in the natural environment.
The equatorial region receives heavy rainfall and the temperature is
also high. With the result, tall and
thick trees thrive here. As such, the
forests in this region provide thick vegetation cover. This makes it possible to have a large
variety of animals here. The common
animals found here are different types of monkeys, elephants, crocodiles and
insect - eating animals like armadillos, snakes, etc. In the grasslands, the number of animals is
less as compared to the equatorial forests because of less vegetation. The common animals are lion, cheetah,
leopard, deer, rabbit, etc. In the polar
region, the animals have thick fur on their body to protect them from the
extreme cold. The common animals found
here are penguin, polar bear, yak, fox, etc.
Armadillo Polar bear Yak Penguins HUMAN IMPACT ON THE ECOSYSTEM Due to
the rapid increase in population of the world, the areas under the forests are
fast decreasing Man has cleared forests for the translates of agriculture,
habitation and the expansion of industries.
As a result the ecological balance is highly disturbed all over the
world. This is having a far reaching
effect on the in the global temperature.
A few glaciers have also started melting in the polar ice - caps. 44
It is high time that
man should realize his mistakes and stop tampering with the nature. In order to maintain the ecological balance,
afforestation should be taken up on a large scale. Hunting of animals should be strictly
banned. For the preservation of
different animal species, the government has set up wildlife sanctuaries,
national parks and biosphere reserves.
These are a few measures to maintain ecological balance of the
environment. Many non - governmental
organizations have also come forward to help in protecting different types of
animal species. Tiger roaming freely in
Kanha National Park Nanda Devi Bio - reserve Do You Know? Conservation and preservation are used for
wildlife management. Conservation refers
to 'wise use and preservation refers to' non use 'to protect the animals and
their habitats for future generations.
Keywords. afforestation: the
process of improving a forest especially on land not previously forested or
land cleared earlier due to deforestation.
biosphere reserved: an area of land or water that is protected by law
in order to support the conservation of eco - systems as well as the
sustainable co - existence of man with nature, deciduous trees: trees that shed
their leaves in the same season every
year. ecological balance: a term
describing how ecosystems are organized in a state of stability where species
co-exist with other species and their environment. habitat: the part of environment that offers
the conditions favourable for a plant or an animal to exist. national parks: large areas of public land
set aside for protection of their natural beauty, native plants, animals and
habitats in which they live. Generally
national parks make the core zone of a biosphere reserve in which wildlife is
strictly protected and no human activity is permitted. wildlife sanctuary: a place that is set aside
for the purpose of protecting wild animals, generally endangered species, where
these live, breed and are closely monitored for their survival. 45
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