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ANIMAL BIOTECHNOLOGY

ASSIGNMENT NO: 1
COMPONENTS AND CHARACTERISTIC FEATURES
OF ATMOSPHERE, HYDROSPHERE AND
LITHOSPHERE

Submitted to: Dr
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Describe the components and characteristic features of atmosphere, hydrosphere
and lithosphere
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, = sphere of air], the mixture of gases surrounding a celestial body with

sufficient gravity to maintain it
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Components and Characteristics of the Earth's Atmosphere
The first 40 to 50 mi (64–80 km) above the earth contains 99% of the total mass of the earth's
atmosphere and is generally of a uniform composition, except for a high concentration of ozone,
known as the ozone layer, at 12–30 mi (19–50 km)
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09%; oxygen, 20
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93%; carbon dioxide, 0
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The lower atmosphere contains varying amounts of water vapor,
which determine its humidity
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The air also carries many kinds of dust, of meteoric as well
as terrestrial origin, and microorganisms, pollen, salt particles, and various gaseous and solid
impurities resulting from human activity (seepollution)
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The instrument used to
measure air pressure is called a barometer
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Layers of atmosphere:
The earth's atmosphere is composed of distinct layers
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1 km) at the poles, to about 7 mi (11
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1 km) at the equator
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Throughout the troposphere temperature
decreases with altitude at an average rate of about 3
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Above the troposphere is an atmospheric ozone
layer, which is also the lower layer of the stratosphere
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Above this layer is the
mesosphere which extends to about 50 mi (80 km above the earth); the temperature sharply
decreases from around 20°F (10°C) at the base of the mesosphere to - 166°F ( - 110°C) before it
begins to rise at the top of the mesosphere
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The final layer is the exosphere,
which gradually gets thinner as it reaches into the vacuum of space at around 435 mi (700 km)
above the earth's surface; the atmosphere is so attenuated at this altitude that the average distance
air molecules travel without colliding is equal to the radius of the earth
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Certain layers of the atmosphere within
the main regions exhibit characteristic properties
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The ionosphere is in the range (50–400 mi/80–640 km) that contains a high
concentration of electrically charged particles (ions); these particles are responsible for reflecting
radio signals important to telecommunications
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Weatherconsists of
the day-to-day fluctuations of environmental variables and includes the motion of wind and
formation of weather systems such as hurricanes
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The atmosphere
protects earth's life forms from harmful radiation and cosmic debris
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Meteors strike the thermosphere and mesosphere and burn
from the heat generated by air friction
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It is essential to all forms of life
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The oceans act as giant heat banks capable of absorbing large quantity of
heat
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Water is referred to as universal
solvent
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It has been estimated that there are 1386 million cubic kilometres of water on Earth
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Saltwater
accounts for 97
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Fresh water accounts for only 2
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Of this fresh water,
68
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29
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Only 0
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The total mass of the Earth's hydrosphere is
about 1
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023% of Earth's total mass
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Approximately 75% of Earth's surface, an area of some 361 million square kilometers (139
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The average salinity of Earth's oceans is about
35 grams of salt per kilogram of sea water (3
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Sources of water: Rainwater, oceans, rivers, lakes, streams, ponds and springs are natural
sources of water
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Rain Water: Rain water collects on the earth in the form of surface water and underground water
Surface Water: Water present on the surface of the earth in the form of oceans, rivers, lakes,
ponds and streams is called surface water
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Rivers flow into the sea
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This is underground water
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It can be obtained by digging wells, sinking tube wells, etc
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Reservoirs include atmospheric moisture (snow, rain and clouds),streams, oceans,
rivers, lakes, groundwater, subterranean aquifers, polar icecaps and saturated soil
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Most evaporation comes from the oceans and is returned to the
earth as snow or rain
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Transpiration refers
to the expiration of water through the minute pores or stomata of trees
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Estuary: It is the point where rivers meet the sea
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Estuary are also called bay, sound or
fjord
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Lithosphere: The solid component of earth is called Lithosphere
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The crust is the outermost solid layer of the
earth
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Hence the layer lining the continents floor is called as granite layer
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The
crust and the upper mantle together constitute the lithosphere
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The
average composition of the important elements in the earth crust is given in table
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6
Silicon
27
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1
Iron
5
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6
Sodium
2
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6
Magnesium
2
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8
0
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5
0
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0
1
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8
0
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6
21
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5
1
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9
2
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4
1
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If the volume of different atoms (or ions) is calculated, oxygen makes up more
than 90 percent of the volume
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It is subdivided into the upper,
transition and the lower zones
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This region contains predominantly three silicate
material olivine, pyroxene and garnet
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The above mentioned three components of the upper mantle are also
present in this region but in chemically modified forms
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The
main components are magnesium oxide, iron oxide and silica
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9
1
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6
0
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38
0
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14
0
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08

48
31
13
3
2
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1
0
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43
0
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13
0
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Most of the oxygen in
the upper mantle and transition zone is present in the form of silicates, and therefore, silicon is
the second most abundant element in the mantle
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Composition of Core:
The outer core extends from the depth of about 2900 kms to about 5080 kms while the inner core
extends from about 5080 kms to about 6370 kms
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The composition of outer core is believed to be nickel and iron
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Minerals and Rocks:
Minerals are naturally occurring inorganic crystalline substances with physical and chemical
properties within prescribed limits
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There are over
2000 minerals, however, only a few are necessary to identify most of the rocks
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Their composition, texture and structure
determine the type of the soil
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It is the habitat of microorganisms and burrowing animals
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Weathering of Rocks:
There are three kinds of soil forming rocks viz
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Soil formation results from its disintegration or weathering of parent rock by physical, chemical
or biological agents
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Regoliths under the
influence of other pedogenic processes finally develop into mature soil
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It occurs in deserts, at high altitudes and latitudes specially at places where sparse
vegetation grow over the rocks
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Water is the
most potent weathering agent
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(c) Biological Weathering:
Certain organisms like bacteria, protozoans, fungi and nemetodes as well as lichens and mosses
colonize the rocks and transfer it into a dynamic system storing energy and synthesizing organic
material
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Weathered rocks are changed into regoliths that are again changed into soil
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Pedogenesis is by and large a biological phenomenon
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These activities convert the weathered earth crust into true soil consisting of mineral matrix in
association with a variety of organic compounds supporting rich population of micro organisms
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Therefore, the soil when fully developed can be observed having
a number of horizons, starting from surface to downwards
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Biota of the Soil:

The organic matter of the soil supports a complex micro flora and fauna and often a complex
biota of higher communities
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Microflora:
It includes bacteria, soil fungi and algae
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Symbiotic fungi live on the roots of plants whereas fungi
depend on the dead organic matter of the soil
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Microfauna:
Protozoa, rotifers, mites, nematodes, copepods collectively constitute the micro-fauna
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Protozoans like amoeba, ciliates and flagellates occur
near the surface soil
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Mesofauna:
The animals ranging in size from 200 µ to 1 cm
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Among insects,
collembola is the main soil insect
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Mites flourish in moist organic soil
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Macroflora:
Soil supports a wide variety of plants like herbs, shrubs and trees
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Those growing on saline soils are called Halophytes
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Plants that grow on rock surfaces are called
lithophytes whereas those which grow on rock cervices are called as charmophytes

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