The document discusses key concepts relating to life on Earth, including the biosphere, ecosystems, and biogeochemical cycles. The biosphere encompasses all life and interactions between the lithosphere, hydrosphere, and atmosphere. Ecosystems refer to interactions between living and non-living factors within a defined area. Major biogeochemical cycles, like the carbon, water, oxygen, and nitrogen cycles, involve the exchange and reuse of key elements between organisms and the environment.

1. LIFE ON EARTH

2. SOME CONCEPTS
• LITHOSPHERE: the land portion on the Earth surface.
• HYDROSPHERE: The portion of the Earth covered with water
• ATMOSPHERE: The presence of gases in the air and this blanket of
gases around the Earth Surface is called atmosphere.
• BIOSPHERE: The interaction between these three realms i.e.
Lithosphere, Atmosphere and Hydrosphere is called Biosphere.
• Biosphere is the most important realm of the Earth Surface
because
• 1.it contains all forms of life including animal, plant and human
life.
• 2. all components of biosphere like land, water and air are present
in it and are required for the existence of the humans.
• 3.the interactions between land , water and air are required for
the growth , development of plant and animal life.

3. • HABITAT: the presence of physical and chemical
factors that are responsible for particular plant
and animal species in an area.
• ECOLOGY: All plants and animals interact with
each other. They are interlinked and
interdependent on each other. This science of
study of interactions between plant, animal,
humans and environment is called Ecology. This
concept was introduced by Ernest Haeckel.
• BIOME: The geographical area where the
interactions occur between plant and anima life is
called BIOME. Example: tropical rain forest,
Grassland, Desert, Tundra, Taiga etc.

4. • ECOSYSTEM: The system of interactions between
plant, animal, humans and environment is called
Ecosystem.
• TYPES OF ECOSYSTEM:
• There are two types of Ecosystem:
• 1.Terrestrial Ecosystem: The presence of plant and
animal species over a large geographical area (land) is
called Terrestrial Ecosystem. Forest , Grasslands etc
are the example of Terrestrial Ecosystem.
• 2. Aquatic Ecosystem: The presence of plant and
animal species over a large geographical area (water )
is called Aquatic Ecosystem. Marine Ecosystem,
Aquatic Ecosystem etc are the example of Aquatic
Ecosystem.

5. • Structure of Ecosystem:
• The structure of ecosystem includes various biotic
and abiotic factors.
• Abiotic Factors refers to non living factors like
rainfall, temperature , sunlight, soil condition etc.
• Biotic factors refers to living factors like producers,
consumers and decomposers. Producers are the
green plants which prepare their food with help of
photosynthesis. Consumers are the animals which
consume plants and animlas. The animals which
feed on the plants are called herbivores or primary
consumers like cow , deer. The animals which feed
on animals are called secondary consumers like
lion,tiger. The various microorganisms like
Earthworm, bacteria which help in breakdown of
dead matter is called Decomposers.

6. • Flow of Energy:
• The main source of energy is the solar energy.
• The energy passes from one organism to
another in form of food.
• This transfer of energy during process of food
chain from one level to another is called Flow
Of Energy.

7. Food chain
Producers
(plants)
By primary
consumers(herbivores)
Secondary
consumers(carnivores)
Destroyed by
decomposers
•This sequence of creating food, being eaten and resulting the transfer of energy from one
level to another is called Food chain.
•There are two types of food chain:
•Grazing food chain(starts from producers (plants) and end till Consumers(carnivores).
•Detritus Food Chain( starts from producers(plants) and end till decaying of organic matter by
decomposers.

8. Food Web
• The network of food chain which exist over an
area is called Food Web.

9. Biogeochemical Cycles
• Sun is the basic source of energy and by the
process of photosynthesis plants prepare their
food.
• Various chemical elements like carbon dioxide
gas, oxygen gas, water etc are used in the making
and sharing of food.
• This cyclic movement of chemical elements of
biosphere between the organism(plant, animal
and humans) and the environment are referred
to as Biogeochemical Cycles.

10. 1.Hydrological Cycle/Water Cycle
• Water moves in a continuous cycle and changes from one form to
another.
• Water from the surface of earth evaporates on heating ad changes
from liquid to gas. This process of change of water vapour from
liquid to gas is called evaporation.
• Water vapour is carried by the air to a particular height where
condensation of water vapour takes place and result in forming
clouds. This process of change of water vapour from gas to solid is
called Condensation.
• When the cloud is not able to hold the condensed water vapours,
they fall on the surface of Earth in form of rain, snow etc. This
process of falling of water vapour on surface of earth in form of
rain or snow is called precipitation.
• This continuous interchange of forms of water on surface of earth
is called Hydrological Cycle.

12. 2. Carbon Cycle
• Atmospheric carbon dioxide is used by plants for the
process of photosynthesis.
• Plants are either taken by herbivores animals or get
decomposed by the microorganisms. Animals also add
the carbon dioxide back in the air through respiration
process.
• microorganisms decompose the organic matter and
add carbon dioxide in the air through respiration
process.
• This is how carbon dioxide is used by the plants for
preparing food and in added back in the atmosphere
too. This is how this cycle goes on and Carbon Dioxide
balance is maintained in the atmosphere.

13. 3. Oxygen Cycle
• Plants release oxygen in air and consume
carbon dioxide when they prepare food with
the help of photosynthesis.
• Humans consume oxygen and release carbon
dioxide in the air.
• This is how the balance of oxygen is
maintained in the atmosphere by both plants
and humans

14. 4. Nitrogen Cycle
• 78% of the air have nitrogen in it.
• Few organisms like Rhizombium absorb and fix
nitrogen from the air and it is used by the plants
as a important nutrient for the growth of plants.
• Remains of dead plants and animals is being
decomposed by the decomposers and thus
nitrogen is added again in the atmosphere by
them through the process called denitrification.