2. Dimensions Of Environment - Physical
Introduction:
Earth is the only planet that has shown signs of life. Our planet
that was born of fire has undergone change since its evolution
and today it has emerged as a perfect system. The natural
forces have given rise to an environment that was favorable for
growth of life. These forces have gained a perfect of balance
and each of the components is dependent on each other. Now
the earth looked more like a single living organism. The Greeks
called the earth as Gaia or the Goddess Earth that was
responsible for the well being of her domain.
3. Earth’s environment can be divided into four divisions :
Atmosphere
Biosphere
Hydrosphere
Lithosphere
The names of the four spheres are derived from the Greek words
for stone (litho), air (atmo), water (hydro), and life (bio).
4. Lithosphere :
The lithosphere is the solid, rocky crust covering entire planet. The
crust is inorganic and is composed of minerals. It covers the entire
surface of the earth from the tallest top of Mount Everest (8850 mts)
to the deepest bottom of the Mariana Trench (11033 mts). It
consists of earth’s crust and upper mantle. Lithosphere is important
for rocks, minerals, underground water, soil, etc.
5. Hydrosphere :
The hydrosphere is composed of all of the water on or above the
earth’s surface. This includes the oceans, rivers, lakes underground
water and even the moisture in the air. 97 % of the earth’s water is
in the oceans. The remaining 3 % is fresh water; three-quarters of
the fresh water is solid and exists in ice sheets.
6. Atmosphere:
The atmosphere is the body of air that surrounds our earth. Most of
our atmosphere is located close to the earth’s surface due to
gravitation force of earth. The air comprises of 78% nitrogen and
21% oxygen; the small amount of carbon dioxide and other gasses.
97% of the atmospheric gasses are concentrated upto a height of
29 kms from the earth’s surface.
7. Biosphere :
The biosphere is life supporting arena of the earth. Plants, animals,
and even one-celled organisms are part of the biosphere. Most of
the planet’s life is found from three meters below the ground to thirty
meters above it and in the top 200 meters of the oceans and seas.
Life cannot sustain just with the presence of soil, water or air but
needs presence of all the three.
8. Components of Environment :
The Physical Components :
The Physical components can be classified into two groups :
Abiotic Components
Biotic components
9. Abiotic Components :
1. Location
2. Altitude
3. Climate a) Temperature
b) Precipitation
4. Soil
5. Geology
10. Biotic Components :
1. Producers:
Oxygen is given out as a by-product of photosynthesis.
The process of photosynthesis can be summarized as follows:
Carbon dioxide + Water + Solar energy Glucose + Oxygen
11. Biotic Components :
2. Consumers:
Organisms that get the nutrients & energy they require by feeding
either directly or indirectly on producers are called consumers or
heterotrophs (other feeders). Some consumers feed on small fragments of
dead plant & animal matter, called detritus.
Consumers are divided into different categories depending upon the food
they consume.
Herbivores (Plant eaters).
Carnivores (Flesh eaters).
Omnivores (Plant & Flesh eaters).
Detritivores.
12. Biotic Components :
3. Food Chain:
All ecosystems are made up of food chains that begin with energy.
The flesh of the herbivore provides nutrition & energy to the
carnivore. Thus, energy is passed on from one organism to another
step by step, thus establishing a link. These links together form a
food chain.
13. Biotic Components :
4. Food Web :
Food chain represents an isolated relationship between the
producers & consumers. In reality or in the environment all elements
are inter-related & inter-dependent and hence we find that the
elements of different food chains are inter-related or inter-dependent
on the elements of different food chains. Such a set of intergraded
food chains is called as a food web.
14. Biotic Components :
5. Levels of Organisms in Nature :
Each food chain consists of different segments or levels known as
tropic level. The points of energy transfer in an environment to an
organism & then from that organism to another define each level.
15. Biotic Components :
6. Energy flow in the ecosystem :
The living organisms need energy for functioning. They use 90% or
more of the energy. Thus at every trophic level 90% of the energy is
lost & only 10% is passed to next level. So the amount of energy
reduces considerably as it passes from one trophic level to another.
Hence, the number of consumers at every stage that can survive
comfortably is always less than at its previous stage.
