Page 41 - EM BIOLOGY NOTES 10TH CLASS PSR DIGITAL BOOKS

9. OUR ENVIRONMENT - OUR CONCERN

 Bio sphere-eco system :- Lesson related 1, 2, 4 marks
Activities Question and
 All the life supporting ones on earth are together called Bio-sphere. videos Answers PDF
pl.scan QR
 Bio-sphere is a large unit. Hence bio-sphere is divided into smaller units pl.scan QR
called eco-systems.
 The word ecosystem was first coined by A.G.Transely in 1935.
 Ecosystem is a living place of some different groups of organisms.
 Ex :- grassland ecosystem, forest ecosystem
desert ecosystem, pond ecosystem
marine ecosystem
 Ecosystem has both abiotic and biotic components.
 All living organisms such as animals, plants and microbes are biotic components.
 Sunlight,soil, air, water, gravity, salts...are the abiotic components.
 In an eco-system living organisms interact among themselves and also with the surround-
ing abiotic components.
 Biotic components are classified into three types. They are :
1. Producers 2. Consumers 3. Decomposers
 Producers :- Plants are the only organisms capable of carrying out photosynthesis and
producing food to all living organisms in any ecosystem.
Due to this reason plants are called producers.
 Consumers :- The organisms which depend directly or indirectly on producers for their
food requirements are called consumers. These are divided into 3 types.
a. Primary consumers b. Secondary consumers c. Tertiary (higher order) consumers
a. Primary Consumers :-
 They feed/eat plants.Herbivores are the primary consumers.
 Ex : Cow, Goat, Sheep, Giraffe, Zebra, Horse, Donkey, Monkey etc ...
b. Secondary Consumers & Tertiary Consumers:-
 The organisms which feed/eat another animals (or) herbivores is called secondary con-
sumers.
 Carnivores are the Secondary Consumers and the Tertiary Consumers.
 Ex : Lion, Tiger, Eagle, Snake, Frog, Vulture ...
c. Decomposers :-
 Some of the organisms in the ecosystem such as Bacteria, fungi are heterotrophic and
obtain their nutrients by decomposing the dead bodies of both producers and consumers.
 These organisms are a special type of consumers and are called decomposers of the eco-
system.
 These are also called as recyclers.
Food chain :-
 There is a feeding relationship between plants and animals.
 All the organisms in an ecosystem derive energy from food to live.
 Food chain shows how energy passed from one organism to another through food.
 Food chain consists of producers, primary consumers, secondary consumers and tertiary
consumers.
 Producers becomes food for primary consumers. Theprimary consumers becomes food for
secondary consumers
 The arrows between each item in a food chain always point from the food of feeder.

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