Ecosystem. - Tamil Nadu Board STD 12 BIO BOTANY Questions

Q 1Choose the most appropriate answer from the given alternatives and write the option code and the corresponding answer.1 Mark

_______ is the climax community of hydrosere.

A
Reed swamp stage
B
Marsh medow stage
C
Shrub stage
✓
Forest stage

Answer: D.

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Q 2Choose the most appropriate answer from the given alternatives and write the option code and the corresponding answer.1 Mark

Statement (I): The first invaded plants in a barren area are called as pioneers.
Statement (II): Marsh meadow stage of hydrosere succession is also called as amphibious stage.

✓
Statement I is correct; Statement II is incorrect.
B
Statement I is incorrect; Statement II is correct.
C
Both Statements I and II are correct.
D
Both Statements I and II are incorrect.

Answer: A.

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Q 3Choose the most appropriate answer from the given alternatives and write the option code and the corresponding answer.1 Mark

Statement (I): Allogenic succession occurs as a result of abiotic factors.
Statement (II): Autogenic succession occurs as result of biotic factors.

A
Statement I is correct; Statement II is incorrect.
B
Statement I is incorrect; Statement II is correct.
✓
Both Statements I and II are correct.
D
Both Statements I and II are incorrect.

Answer: C.

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Q 4Choose the most appropriate answer from the given alternatives and write the option code and the corresponding answer.1 Mark

Succession initiating on a sand referred as

A
Hydrosere
✓
Psammosere
C
Halosere
D
Lithosere

Answer: B.

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Q 5Choose the most appropriate answer from the given alternatives and write the option code and the corresponding answer.1 Mark

Assertion (A): In forest ecosystem, the pyramid of number is spindle shaped.
Reason (R): Tropical level $(T_1)$ of the pyramid occupies large trees which are maxium in number

A
Both A and R are wrong
✓
A is right R is wrong
C
R explains A
D
A is right R is not the correct explanation for A

Answer: B.

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Q 6[ 2 Marks Questions ]2 Marks

The below diagramatic sketch shows the stratisfication of pond ecosystem. Considering it, name X and Y.

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Q 7[ 2 Marks Questions ]2 Marks

Mention any two vital biomolecules that requires phosphorous for their biosynthesis.

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Q 8[ 2 Marks Questions ]2 Marks

Frame any two food chain patterns from the given organisms. Each chain must contain a minimum of four organisms.
Diatoms, Hawk, Rabbit, Vallisneria Stoke, guppies, grass, snake, large fishes, grasshopper, crane.

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Q 9[ 2 Marks Questions ]2 Marks

According to ten percent law, how many Joules of energy does the individuals at the fourth tropic level will receive; if the individuals at first trophic level receives 1000 Joules of energy?

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Q 10[ 2 Marks Questions ]2 Marks

Nutrients are retained in the ecosystem. Discuss how and name the process through which it is achieved?

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Q 11[ 3 Marks Questions ]3 Marks

What is primary succession?

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Q 12[ 3 Marks Questions ]3 Marks

What are the human activities that disturb an ecosystem?

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Q 13[ 3 Marks Questions ]3 Marks

Point out any three mangrove ecosystem services.