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SOCIAL SCIENCE
1.geography
7TH
presented by :-
Mangal Ram Bairwa(TGT sst.)
GEOGRAPHY
OUR
ENVIRONMENT
Natural Vegetation
and Wildlife
FORESTS
1. TROPICAL EVERGREEN FOREST
Tropical evergreen forests are usually found in
areas receiving more than 200 cm of rainfall
and having a temperature of 15 °C to 30 °C.
They occupy about seven per cent of the
Earth's land surface and harbour more than
half of the planet's terrestrial plants and
animals. Tropical evergreen forests are
dense, multi-layered, and harbour many
types of plants and animals. The trees are
evergreen as there is no period of drought
or frost. The canopy tree species are mostly
tall hardwoods with broad leaves that
release large quantities of water through
transpiration, in a cycle that is important in
raising as much mineral nutrient material as
possible from the soil.
TEMPERATE DECIDUOUS FOREST
Temperate deciduous forests or temperate broadleaf forests are dominated by trees that lose their
leaves each year. They are found in areas where
warm, moist summers alternate with mild
winters.[1] The three major areas of this forest type
occur in the northern hemisphere: eastern North
America, eastern Asia,[2] and Europe. Smaller areas
occur in Australasia and southern South
America.[3] Examples of typical trees
include oak, maple, beech, and elm. The diversity
of tree species is higher in regions where the
winter is milder, and also in mountainous regions
that provide an array of soil types and
microclimates.[4] One of the world's great
protected examples of this forest type is found
in Great Smoky Mountains National Park.[5][6]
GRASSLANDS
Grasslands are areas where the vegetation is
dominated by grasses (Poaceae), however
sedge (Cyperaceae) and rush (Juncaceae)
families can also be found. Grasslands occur
naturally on all continents except Antarctica.
In temperate latitudes, such as northwestern
Europe and the Great
Plains andCalifornia in North America, native
grasslands are dominated by perennial bunch
grass species, whereas in
warmer climates annual species form a
greater component of the vegetation.[1]
Grasslands are found in most ecoregions of
the Earth. For example there are
five terrestrial ecoregion classifications
(subdivisions) of the temperate grasslands,
savannas, and
shrublands biome ('ecosystem'), which is one
of eight terrestrial ecozones of the Earth's
surface.
HUMAN ENVIRONMENT –
SETTLEMENT ,
TRANSPORT AND
COMMUNICATION
TRANSPORT
Transport is the means by which people and goods move.
There are four means of the transportation—
1.Roadways 2.Railways 3. Waterways and 4. Airways
ROADWAYS
The most commonly used means of transport especially for
short distances are road. They can be metalled (pucca) and
unmetalled (kutcha). The roads built underground are called
subways/ under paths
RAILWAYS
The railways carry heavy goods and people over long
distances quickly and cheaply. Indian railway is thelargest in
Asia.
Water transport is movement by means of a watercraft—
such as a barge, boat, ship or sailboat—over a body of
water, such as a sea, ocean, lake, canal or river. The need
for buoyancy is common to watercraft, making the hull a
dominant aspect of its construction, maintenance and
appearance.
A fixed-wing aircraft, commonly called airplane, is a
heavier-than-air craft where movement of the air in
relation to the wings is used to generate lift. The term is
used to distinguish from rotary-wing aircraft, where the
movement of the lift surfaces relative to the air generates
lift. A gyroplane is both fixed-wing and rotary-wing. Fixedwing aircraft range from small trainers and recreational
aircraft to large airliners and military cargo aircraft.
COMMUNICATION
Communication requires a sender, a message,
and a recipient, although the receiver need
not be present or aware of the sender's intent
to communicate at the time of
communication; thus communication can
occur across vast distances in time and space.
Communication requires that the
communicating parties share an area of
communicative commonality. The
communication process is complete once the
receiver has understood the message of the
sender.
LIFE IN THE DESERTS
• A desert is a landscape or region that
receives an extremely low amount
of precipitation, less than enough to
support growth of most plants. Most
deserts have an average annual
precipitation of less than 400
millimetres (16 in).[1] A common
definition distinguishes between true
deserts, which receive less than 250
millimetres (10 in) of average annual
precipitation, and semideserts or
steppes, which receive between 250
millimetres (10 in) and 400 to 500
millimetres (16 to 20 in).
Human life in deserts
A desert is a hostile, potentially deadly environment for
unprepared humans. In hot deserts, high temperatures
cause rapid loss of water due tosweating, and the absence
of water sources with which to replenish it can result
in dehydration and death within a few days. In addition,
unprotected humans are also at risk from heatstroke.
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