CHAPTER – 15
OUR ENVIRONMENT
Environment means everything which surrounds us. It may include living
?
(biotic) and non-living (abiotic) components. So, it may includes besides all
creatures, water & air also.
Environment affect the life and development of an organism in its natural
?
habitat & vice a versa.
Substances that are decomposed are called bio-degredable. Eg. organic
?
wastes while some substances like plastics, some chemicals (DDTs &
fertilizers) are inert and can’t be decomposed, are called Non-biodegradable
Actually non-biodegradable persist in the environment for a long time or may
?
harm the various members of the eco system.
ECO SYSTEM & ITS COMPONENT
All the interacting organisms in an area together with non living components form
an ecosystem. So an ecosystem consists of both biotic (living creatures) and
abiotic components like temperature, rainfall, wind, soil etc.
Ecosystem
Man-made Ecosystem Natural Ecosystem
Eg. Cropland, Aquarium etc.
Aquatic Ecosystem Terrestrial Ecosystem
land Ecosystem
Eg. Forest,
Marine Fresh water Desert, Grassland etc.
Ecosystem Ecosystem
Eg. Sea, Oceans River, Lake,
Pond, pool
All living organisms are classified on the basis of the manner in which they
?
survive in the Ecosystem. These groups include
I Producers– All green plants, blue green algae can produce their food (Sugar
& starch) from in organic substance using light energy (Photosynthesis)
157 X-Science
, II Consumers– Include organisms which depend on the producers either
directly or indirectly for their sustenance. In other word consumers consume
the food produced by producers.
CONSUMERS
Parasite
Herbivores Carnivores Live & feed Omnivores
– Gross eaters Flash Eaters on the host body Feed on both plant
and flesh.
Eg. Cow, dear Lion, Tiger Plasmodium Eg. Crow
III DECOMPOSERS– Fungi & Bacterias which break down (decompose) the
dead plant, animals complex compounds into the simpler one. Thus
decomposers help in the replenishment of the natural resources.
Food chain refers to an arrangement of different biotic groups in a sequence of
enery transfer. These biotic groups are producer herbivores, carnivores.
For Eg. T1 T2 T3
Grass DearA Lion
A 3-setp Food chain
In a food chain, these biotic components where transfer of energy takes place
?
is called a trophic level.
The green plants capture 1% of sunlight falls on their leaves.
?
The flow of energy is unidirectional in a food chain
?
There is gradual decrease in the amount of energy transfer from one trophic
?
level to next trophic level in a food chain
Tertiary
consumers
1kJ
Secondary
Consumer 10kJ
Primary
Consumer 100kJ
Producer
Energy Flow 1000 kJ TROPHIC LEVEL
Energy
So only 10% of Energy is transferred to next trophic level while 90% of energy is
used by present trophic level in its life processes.
158 X-Science
OUR ENVIRONMENT
Environment means everything which surrounds us. It may include living
?
(biotic) and non-living (abiotic) components. So, it may includes besides all
creatures, water & air also.
Environment affect the life and development of an organism in its natural
?
habitat & vice a versa.
Substances that are decomposed are called bio-degredable. Eg. organic
?
wastes while some substances like plastics, some chemicals (DDTs &
fertilizers) are inert and can’t be decomposed, are called Non-biodegradable
Actually non-biodegradable persist in the environment for a long time or may
?
harm the various members of the eco system.
ECO SYSTEM & ITS COMPONENT
All the interacting organisms in an area together with non living components form
an ecosystem. So an ecosystem consists of both biotic (living creatures) and
abiotic components like temperature, rainfall, wind, soil etc.
Ecosystem
Man-made Ecosystem Natural Ecosystem
Eg. Cropland, Aquarium etc.
Aquatic Ecosystem Terrestrial Ecosystem
land Ecosystem
Eg. Forest,
Marine Fresh water Desert, Grassland etc.
Ecosystem Ecosystem
Eg. Sea, Oceans River, Lake,
Pond, pool
All living organisms are classified on the basis of the manner in which they
?
survive in the Ecosystem. These groups include
I Producers– All green plants, blue green algae can produce their food (Sugar
& starch) from in organic substance using light energy (Photosynthesis)
157 X-Science
, II Consumers– Include organisms which depend on the producers either
directly or indirectly for their sustenance. In other word consumers consume
the food produced by producers.
CONSUMERS
Parasite
Herbivores Carnivores Live & feed Omnivores
– Gross eaters Flash Eaters on the host body Feed on both plant
and flesh.
Eg. Cow, dear Lion, Tiger Plasmodium Eg. Crow
III DECOMPOSERS– Fungi & Bacterias which break down (decompose) the
dead plant, animals complex compounds into the simpler one. Thus
decomposers help in the replenishment of the natural resources.
Food chain refers to an arrangement of different biotic groups in a sequence of
enery transfer. These biotic groups are producer herbivores, carnivores.
For Eg. T1 T2 T3
Grass DearA Lion
A 3-setp Food chain
In a food chain, these biotic components where transfer of energy takes place
?
is called a trophic level.
The green plants capture 1% of sunlight falls on their leaves.
?
The flow of energy is unidirectional in a food chain
?
There is gradual decrease in the amount of energy transfer from one trophic
?
level to next trophic level in a food chain
Tertiary
consumers
1kJ
Secondary
Consumer 10kJ
Primary
Consumer 100kJ
Producer
Energy Flow 1000 kJ TROPHIC LEVEL
Energy
So only 10% of Energy is transferred to next trophic level while 90% of energy is
used by present trophic level in its life processes.
158 X-Science
