NCERT Textbook: Human Environment Interactions The Tropical and the Subtropical Region | Social Studies (SST) Class 7 PDF Download

 Page 1


Renuka was excited. Shrikant Uncle was home after a
gap of nearly four months. He was a wildlife photographer
and travelled widely. Renuka’s interest in wildlife and
forests began at an early age, when her uncle introduced
her to books on nature. Pictures of distant lands and
people, who lived there, always fascinated her.
Fig. 6.1: People from various parts of the world
“In these pictures Renuka, you can see people from
different parts of the world – some from dry deserts, some
from frozen lands and some from hot wet rainforests.”
“They look so different from me”, observed Renuka. “They
may look different, but they share the same basic needs
of life – food, clothing and shelter”, explained Shrikant Uncle.
“Their children do the same things as you probably do,
play games, quarrel sometimes and then make-up, sing,
dance and help the families with various things that need
to be done. They live closer to nature and very early in
their lives have learnt to care for nature. They learn how
to catch fish and how to collect material from the forests.”
Reprint 2024-25
Page 2


Renuka was excited. Shrikant Uncle was home after a
gap of nearly four months. He was a wildlife photographer
and travelled widely. Renuka’s interest in wildlife and
forests began at an early age, when her uncle introduced
her to books on nature. Pictures of distant lands and
people, who lived there, always fascinated her.
Fig. 6.1: People from various parts of the world
“In these pictures Renuka, you can see people from
different parts of the world – some from dry deserts, some
from frozen lands and some from hot wet rainforests.”
“They look so different from me”, observed Renuka. “They
may look different, but they share the same basic needs
of life – food, clothing and shelter”, explained Shrikant Uncle.
“Their children do the same things as you probably do,
play games, quarrel sometimes and then make-up, sing,
dance and help the families with various things that need
to be done. They live closer to nature and very early in
their lives have learnt to care for nature. They learn how
to catch fish and how to collect material from the forests.”
Reprint 2024-25
40 OUR ENVIRONMENT
Glossary
LIFE IN THE AMAZON BASIN
Before learning about the Amazon basin, let us look at the
map (Fig. 6.2). Notice that the tropical region lies very
close to the equator; between 10°N and 10°S. So, it is referred
to as the equatorial region. The river Amazon flows through
this region. Notice how it flows from the mountains to the
west and reaches the Atlantic Ocean to the east.
The place where a river flows into another body of
water is called the river’s mouth. Numerous tributaries
join the Amazon River to form the Amazon basin. The
river basin drains portions of Brazil, parts of Peru, Bolivia,
Ecuador, Columbia and a small part of Venezuela.
Name the countries of the basin through which the
equator passes.
Tributaries: These
are small rivers that
join the main river.
The main river along
with all its tributaries
that drain an area
forms a river basin or
the catchment area.
The Amazon Basin is
the largest river basin
in the world.
Fig. 6.2: Fig. 6.2: Fig. 6.2: Fig. 6.2: Fig. 6.2: The Amazon Basin in South America
Do you know?
When Spanish
explorers discovered
the Amazon river,
they were attacked by
a group of local tribes
wearing headgears
and grass skirts.
These people
reminded them of the
fierce tribes of women
warriors known in
ancient Roman
Empire as the
Amazons. Hence the
name Amazon.
Reprint 2024-25
Page 3


Renuka was excited. Shrikant Uncle was home after a
gap of nearly four months. He was a wildlife photographer
and travelled widely. Renuka’s interest in wildlife and
forests began at an early age, when her uncle introduced
her to books on nature. Pictures of distant lands and
people, who lived there, always fascinated her.
Fig. 6.1: People from various parts of the world
“In these pictures Renuka, you can see people from
different parts of the world – some from dry deserts, some
from frozen lands and some from hot wet rainforests.”
“They look so different from me”, observed Renuka. “They
may look different, but they share the same basic needs
of life – food, clothing and shelter”, explained Shrikant Uncle.
“Their children do the same things as you probably do,
play games, quarrel sometimes and then make-up, sing,
dance and help the families with various things that need
to be done. They live closer to nature and very early in
their lives have learnt to care for nature. They learn how
to catch fish and how to collect material from the forests.”
Reprint 2024-25
40 OUR ENVIRONMENT
Glossary
LIFE IN THE AMAZON BASIN
Before learning about the Amazon basin, let us look at the
map (Fig. 6.2). Notice that the tropical region lies very
close to the equator; between 10°N and 10°S. So, it is referred
to as the equatorial region. The river Amazon flows through
this region. Notice how it flows from the mountains to the
west and reaches the Atlantic Ocean to the east.
The place where a river flows into another body of
water is called the river’s mouth. Numerous tributaries
join the Amazon River to form the Amazon basin. The
river basin drains portions of Brazil, parts of Peru, Bolivia,
Ecuador, Columbia and a small part of Venezuela.
Name the countries of the basin through which the
equator passes.
Tributaries: These
are small rivers that
join the main river.
The main river along
with all its tributaries
that drain an area
forms a river basin or
the catchment area.
The Amazon Basin is
the largest river basin
in the world.
Fig. 6.2: Fig. 6.2: Fig. 6.2: Fig. 6.2: Fig. 6.2: The Amazon Basin in South America
Do you know?
When Spanish
explorers discovered
the Amazon river,
they were attacked by
a group of local tribes
wearing headgears
and grass skirts.
These people
reminded them of the
fierce tribes of women
warriors known in
ancient Roman
Empire as the
Amazons. Hence the
name Amazon.
Reprint 2024-25
HUMAN ENVIRONMENT INTERACTIONS: THE TROPICAL AND THE SUBTROPICAL REGION 41
CLIMATE
As you now know, the Amazon Basin stretches directly
on the equator and is characterized by hot and wet climate
throughout the year. Both day and nights are almost
equally hot and humid. The skin feels sticky. It rains
almost everyday, that too without much warning. The
day temperatures are high with very high humidity. At
night the temperature goes down but the humidity
remains high.
RAINFORESTS
As it rains heavily in this region, thick forests
grow (Fig. 6.3). The forests are in fact so thick
that the dense “roof” created by leaves and
branches does not allow the sunlight to reach
the ground. The ground remains dark and damp.
Only shade tolerant vegetation may grow here.
Orchids, bromeliads grow as plant parasites.
The rainforest is rich in
fauna. Birds such as toucans (Fig. 6.4),
humming birds, macaw with their
brilliantly coloured plumage, oversized
bills for eating make them different
from birds we commonly see in India.
These birds also make loud sounds in
the forests. Animals like monkeys,
sloth and ant-eating tapirs are found
here (Fig. 6.5). Various species of reptiles and snakes
also thrive in these jungles. Crocodiles, snakes, pythons
abound. Anaconda and boa constrictor are some of the
species. Besides, the basin is home to thousands of
species of insects. Several
species of fishes including the
flesh-eating Piranha fish is
also found in the river. This
basin is thus extraordinarily
rich in the variety of life found
there.
PEOPLE OF THE RAINFORESTS
People grow most of their food in small areas after clearing
some trees in the forest. While men hunt and fish along
the rivers, women take care of the crops. They mainly grow
Do you know?
Bromeliads are
special plants that
store water in their
leaves. Animals like
frogs use these
pockets of water for
laying their eggs.
Let’s do
Some TV channels
broadcast
documentaries on the
wildlife of the world.
Try to watch some of
the films and share
your experience with
the class.
Fig. 6.3 : The Amazon Forest
Fig. 6.4 : Toucans
Fig. 6.5 : Tapir
Reprint 2024-25
Page 4


Renuka was excited. Shrikant Uncle was home after a
gap of nearly four months. He was a wildlife photographer
and travelled widely. Renuka’s interest in wildlife and
forests began at an early age, when her uncle introduced
her to books on nature. Pictures of distant lands and
people, who lived there, always fascinated her.
Fig. 6.1: People from various parts of the world
“In these pictures Renuka, you can see people from
different parts of the world – some from dry deserts, some
from frozen lands and some from hot wet rainforests.”
“They look so different from me”, observed Renuka. “They
may look different, but they share the same basic needs
of life – food, clothing and shelter”, explained Shrikant Uncle.
“Their children do the same things as you probably do,
play games, quarrel sometimes and then make-up, sing,
dance and help the families with various things that need
to be done. They live closer to nature and very early in
their lives have learnt to care for nature. They learn how
to catch fish and how to collect material from the forests.”
Reprint 2024-25
40 OUR ENVIRONMENT
Glossary
LIFE IN THE AMAZON BASIN
Before learning about the Amazon basin, let us look at the
map (Fig. 6.2). Notice that the tropical region lies very
close to the equator; between 10°N and 10°S. So, it is referred
to as the equatorial region. The river Amazon flows through
this region. Notice how it flows from the mountains to the
west and reaches the Atlantic Ocean to the east.
The place where a river flows into another body of
water is called the river’s mouth. Numerous tributaries
join the Amazon River to form the Amazon basin. The
river basin drains portions of Brazil, parts of Peru, Bolivia,
Ecuador, Columbia and a small part of Venezuela.
Name the countries of the basin through which the
equator passes.
Tributaries: These
are small rivers that
join the main river.
The main river along
with all its tributaries
that drain an area
forms a river basin or
the catchment area.
The Amazon Basin is
the largest river basin
in the world.
Fig. 6.2: Fig. 6.2: Fig. 6.2: Fig. 6.2: Fig. 6.2: The Amazon Basin in South America
Do you know?
When Spanish
explorers discovered
the Amazon river,
they were attacked by
a group of local tribes
wearing headgears
and grass skirts.
These people
reminded them of the
fierce tribes of women
warriors known in
ancient Roman
Empire as the
Amazons. Hence the
name Amazon.
Reprint 2024-25
HUMAN ENVIRONMENT INTERACTIONS: THE TROPICAL AND THE SUBTROPICAL REGION 41
CLIMATE
As you now know, the Amazon Basin stretches directly
on the equator and is characterized by hot and wet climate
throughout the year. Both day and nights are almost
equally hot and humid. The skin feels sticky. It rains
almost everyday, that too without much warning. The
day temperatures are high with very high humidity. At
night the temperature goes down but the humidity
remains high.
RAINFORESTS
As it rains heavily in this region, thick forests
grow (Fig. 6.3). The forests are in fact so thick
that the dense “roof” created by leaves and
branches does not allow the sunlight to reach
the ground. The ground remains dark and damp.
Only shade tolerant vegetation may grow here.
Orchids, bromeliads grow as plant parasites.
The rainforest is rich in
fauna. Birds such as toucans (Fig. 6.4),
humming birds, macaw with their
brilliantly coloured plumage, oversized
bills for eating make them different
from birds we commonly see in India.
These birds also make loud sounds in
the forests. Animals like monkeys,
sloth and ant-eating tapirs are found
here (Fig. 6.5). Various species of reptiles and snakes
also thrive in these jungles. Crocodiles, snakes, pythons
abound. Anaconda and boa constrictor are some of the
species. Besides, the basin is home to thousands of
species of insects. Several
species of fishes including the
flesh-eating Piranha fish is
also found in the river. This
basin is thus extraordinarily
rich in the variety of life found
there.
PEOPLE OF THE RAINFORESTS
People grow most of their food in small areas after clearing
some trees in the forest. While men hunt and fish along
the rivers, women take care of the crops. They mainly grow
Do you know?
Bromeliads are
special plants that
store water in their
leaves. Animals like
frogs use these
pockets of water for
laying their eggs.
Let’s do
Some TV channels
broadcast
documentaries on the
wildlife of the world.
Try to watch some of
the films and share
your experience with
the class.
Fig. 6.3 : The Amazon Forest
Fig. 6.4 : Toucans
Fig. 6.5 : Tapir
Reprint 2024-25
42 OUR ENVIRONMENT
Fig. 6.6: Gradual Destruction of Forests
Do you know?
Slash and Burn is a
way of cultivating land
where farmers clear a
piece of land by
slashing or cutting
down trees and bushes.
These are then burnt,
which releases the
nutrients into the soil.
Now crops are grown in
this cleared field for a
few years.
After repeatedly
using the patch of
land, the soil looses
its nutrients. So it is
abandoned. Then they
clear another plot of
land to plant. In the
mean time young
trees grow in the old
field. In this way soil
fertility is restored.
People can then
return to it and start
cultivating it again.
tapioca, pineapple and sweet potato. As hunting and fishing
are uncertain it is the women who keep their families alive
by feeding them the vegetables they grow. They practice
“slash and burn agriculture”. The staple food is manioc,
also known as cassava that grows under the ground like
the potato. They also eat queen ants and egg sacs. Cash
crops like coffee, maize and cocoa are also grown.
The rainforests provide a lot of wood for the houses.
Some families live in thatched houses shaped like
beehives. There are other large apartment-like houses
called “Maloca” with a steeply slanting roof.
Life of the people of the Amazon basin is slowly
changing. In the older days the heart of the forest, could
be reached only by navigating the river. In 1970 the Trans
Amazon highway made all parts of the rainforest
accessible. Aircrafts and helicopters are also used for
reaching various places. The indigenous population was
pushed out from the area and forced to settle in new
areas where they continued to practice their distinctive
way of farming.
The developmental activities are leading to the gradual
destruction of the biologically diverse rainforests. It is
estimated that a large area of the
rainforest has been disappearing
annually in the Amazon basin.
You can see that this
destruction of forests has
a much wider implication
(Fig. 6.6). The topsoil
is washed away as
the rains fall and
the lush forest
turns into
a barren
landscape.
Reprint 2024-25
Page 5


Renuka was excited. Shrikant Uncle was home after a
gap of nearly four months. He was a wildlife photographer
and travelled widely. Renuka’s interest in wildlife and
forests began at an early age, when her uncle introduced
her to books on nature. Pictures of distant lands and
people, who lived there, always fascinated her.
Fig. 6.1: People from various parts of the world
“In these pictures Renuka, you can see people from
different parts of the world – some from dry deserts, some
from frozen lands and some from hot wet rainforests.”
“They look so different from me”, observed Renuka. “They
may look different, but they share the same basic needs
of life – food, clothing and shelter”, explained Shrikant Uncle.
“Their children do the same things as you probably do,
play games, quarrel sometimes and then make-up, sing,
dance and help the families with various things that need
to be done. They live closer to nature and very early in
their lives have learnt to care for nature. They learn how
to catch fish and how to collect material from the forests.”
Reprint 2024-25
40 OUR ENVIRONMENT
Glossary
LIFE IN THE AMAZON BASIN
Before learning about the Amazon basin, let us look at the
map (Fig. 6.2). Notice that the tropical region lies very
close to the equator; between 10°N and 10°S. So, it is referred
to as the equatorial region. The river Amazon flows through
this region. Notice how it flows from the mountains to the
west and reaches the Atlantic Ocean to the east.
The place where a river flows into another body of
water is called the river’s mouth. Numerous tributaries
join the Amazon River to form the Amazon basin. The
river basin drains portions of Brazil, parts of Peru, Bolivia,
Ecuador, Columbia and a small part of Venezuela.
Name the countries of the basin through which the
equator passes.
Tributaries: These
are small rivers that
join the main river.
The main river along
with all its tributaries
that drain an area
forms a river basin or
the catchment area.
The Amazon Basin is
the largest river basin
in the world.
Fig. 6.2: Fig. 6.2: Fig. 6.2: Fig. 6.2: Fig. 6.2: The Amazon Basin in South America
Do you know?
When Spanish
explorers discovered
the Amazon river,
they were attacked by
a group of local tribes
wearing headgears
and grass skirts.
These people
reminded them of the
fierce tribes of women
warriors known in
ancient Roman
Empire as the
Amazons. Hence the
name Amazon.
Reprint 2024-25
HUMAN ENVIRONMENT INTERACTIONS: THE TROPICAL AND THE SUBTROPICAL REGION 41
CLIMATE
As you now know, the Amazon Basin stretches directly
on the equator and is characterized by hot and wet climate
throughout the year. Both day and nights are almost
equally hot and humid. The skin feels sticky. It rains
almost everyday, that too without much warning. The
day temperatures are high with very high humidity. At
night the temperature goes down but the humidity
remains high.
RAINFORESTS
As it rains heavily in this region, thick forests
grow (Fig. 6.3). The forests are in fact so thick
that the dense “roof” created by leaves and
branches does not allow the sunlight to reach
the ground. The ground remains dark and damp.
Only shade tolerant vegetation may grow here.
Orchids, bromeliads grow as plant parasites.
The rainforest is rich in
fauna. Birds such as toucans (Fig. 6.4),
humming birds, macaw with their
brilliantly coloured plumage, oversized
bills for eating make them different
from birds we commonly see in India.
These birds also make loud sounds in
the forests. Animals like monkeys,
sloth and ant-eating tapirs are found
here (Fig. 6.5). Various species of reptiles and snakes
also thrive in these jungles. Crocodiles, snakes, pythons
abound. Anaconda and boa constrictor are some of the
species. Besides, the basin is home to thousands of
species of insects. Several
species of fishes including the
flesh-eating Piranha fish is
also found in the river. This
basin is thus extraordinarily
rich in the variety of life found
there.
PEOPLE OF THE RAINFORESTS
People grow most of their food in small areas after clearing
some trees in the forest. While men hunt and fish along
the rivers, women take care of the crops. They mainly grow
Do you know?
Bromeliads are
special plants that
store water in their
leaves. Animals like
frogs use these
pockets of water for
laying their eggs.
Let’s do
Some TV channels
broadcast
documentaries on the
wildlife of the world.
Try to watch some of
the films and share
your experience with
the class.
Fig. 6.3 : The Amazon Forest
Fig. 6.4 : Toucans
Fig. 6.5 : Tapir
Reprint 2024-25
42 OUR ENVIRONMENT
Fig. 6.6: Gradual Destruction of Forests
Do you know?
Slash and Burn is a
way of cultivating land
where farmers clear a
piece of land by
slashing or cutting
down trees and bushes.
These are then burnt,
which releases the
nutrients into the soil.
Now crops are grown in
this cleared field for a
few years.
After repeatedly
using the patch of
land, the soil looses
its nutrients. So it is
abandoned. Then they
clear another plot of
land to plant. In the
mean time young
trees grow in the old
field. In this way soil
fertility is restored.
People can then
return to it and start
cultivating it again.
tapioca, pineapple and sweet potato. As hunting and fishing
are uncertain it is the women who keep their families alive
by feeding them the vegetables they grow. They practice
“slash and burn agriculture”. The staple food is manioc,
also known as cassava that grows under the ground like
the potato. They also eat queen ants and egg sacs. Cash
crops like coffee, maize and cocoa are also grown.
The rainforests provide a lot of wood for the houses.
Some families live in thatched houses shaped like
beehives. There are other large apartment-like houses
called “Maloca” with a steeply slanting roof.
Life of the people of the Amazon basin is slowly
changing. In the older days the heart of the forest, could
be reached only by navigating the river. In 1970 the Trans
Amazon highway made all parts of the rainforest
accessible. Aircrafts and helicopters are also used for
reaching various places. The indigenous population was
pushed out from the area and forced to settle in new
areas where they continued to practice their distinctive
way of farming.
The developmental activities are leading to the gradual
destruction of the biologically diverse rainforests. It is
estimated that a large area of the
rainforest has been disappearing
annually in the Amazon basin.
You can see that this
destruction of forests has
a much wider implication
(Fig. 6.6). The topsoil
is washed away as
the rains fall and
the lush forest
turns into
a barren
landscape.
Reprint 2024-25
HUMAN ENVIRONMENT INTERACTIONS: THE TROPICAL AND THE SUBTROPICAL REGION 43
LIFE IN THE GANGA-BRAHMAPUTRA BASIN
The tributaries of rivers Ganga and
Brahmaputra together form the
Ganga-Brahmaputra basin in the
Indian subcontinent (Fig. 6.8). The
basin lies in the sub-tropical region
that is situated between 10°N to 30°N
latitudes. The tributaries of the River
Ganga like the Ghaghra, the Son, the
Chambal, the Gandak, the Kosi and
the tributaries of Brahmaputra drain
it. Look at the atlas and find names
of some tributaries of the River
Brahmaputra.
The plains of the Ganga and the
Brahmaputra, the mountains and the foothills of the
Fig. 6.8: Ganga-Brahmputra Basin
Fig. 6.7 Brahmaputra river
Reprint 2024-25