Selina Concise Class 8 Biology Solution Chapter No. 4- ‘Ecosystems’ For ICSE Board Students.
Selina Concise Biology Solutions for Class 8th Chapter 4 Ecosystems with easy language, expert answers and doubt clearing sections. The book is especially designed keeping in mind the syllabus of ICSE board and the difficulty level faced by the students of ICSE boards Class 8.
Multiple choice questions
1.) a.) The term “ecosystem” is derived from the Greek word “Oikos” meaning.
i) Body weight
ii) Food
iii) House
iv) Size
Ans. Ecosystem is derived from the Greek word “Oikos” which means a “house”, a dwelling place with the inhabitants living together and interacting with each other and also with their physical environment in some definite ways.
b.) Rat in any food chain would occupy the position of
i) Tertiary consumer
ii) Secondary consumer
iii) Primary consumer
iv) Producer
Ans. Rats eat plants which are producers.
c.) Evergreen broad leaved trees are characteristic of
i) Tropical rain forests
ii) Temperate deciduous forests
iii) Coniferous forests
iv) All of the above types of forests.
d.) The number of steps in a food chain can never be more than
i) Four ii) Five
iii) Six
iv) Seven
Ans. The number of steps in different food chains may vary from 2 to 5 and very rarely these can be 6 but never 7.
Short Answer Questions
1.) Mention if the following statements are true(T) or false (F)
a.) Snakes are primary consumers. False
b.) Some humans are strictly primary consumers while others are secondary or tertiary consumers as well. True
c.) No ecosystem can survive without light. True
2.) Match the following
a) Grass i) Carnivore
b) Deer ii) Decomposers
c) Cobra iii) Primary consumer
d) Vulture iv) Autotroph
e) Microbes v) Scavenger
Ans. a – iv, b- iii, c – i , d – v , e – ii
3.) Rewrite the following in their correct sequence in a food chain.
a.) Snake –> Grasshopper –> Grass –> Frog
Ans. Grass –> Grasshopper –> Frog –> Snake
b.) Grass –> Tiger –> Deer
Ans. Grass –> Deer –> Tiger
c.) Snake –> Peacock –> Rat –> Wheat
Ans. Wheat –> Rat –> Snake –> Peacock
Long Answer Questions
1.) Differentiate among primary, secondary and tertiary consumers. Give one example of each in a food chain.
Ans. Primary consumers eat the plants directly or eat their fruits or even suck the plant juice.
Example: Grass –> Deer –> Lion
Secondary consumers: They capture the herbivores and eat their flesh.
Example: Grass –> Grasshopper –> Frog –> Snake
Tertiary consumers: The organisms that eat secondary consumers are called tertiary consumers.
Example: Grass –> Rabbit –> Snake –> Hawk
2.) Define the terms:
a.) Flora: Flora means the naturally occurring in a particular area
b.) Fauna: Fauna means the animals naturally living in that area.
3.) List any three members each of the flora and fauna of tropical rain forests.
Ans. Flora: Evergreen trees, bamboos, ferns and shrubs.
Fauna: Jungle cats, leopards, monkeys and snakes
4.) Define the following terms and give two examples in each case.
a) Autotrophs: Plants that produce their own food through photosynthesis and are therefore categorized as autotrophs. Example: Shrubs, grasses
b) Consumers: An animal that eats a plant or an another animal. Example: Frog and Snake
c) Food chain: Food chain is a linear sequence of organisms in which each organism eats the lower member and is itself eaten by the next higher member.
Wheat –> Rat –> Snake –> Peacock
Grass –> Deer –> Tiger
d) Symbiosis: In this interaction both the interacting species are benefitted. Example: lichens, fungus and a photosynthetic algae,
e) Parasitism: In this interaction, one partner receives advantage while the other is at a loss. Example: Human liver fluke, Plasmodium
f) Predation: Predation is nature’s way of transferring energy. A predator catches and kills other organism for food. Example: Tiger and deer, house sparrow and seed.