Page 84 - Biology - XII

Q6. Analogous organs are diff erent from homologous organs. Mention it.
Ans. Analogous organs Homologous organs

1. Structurally diff erent, but similar in function. 1. Structurally similar, but diff ers in function.

2. Result of convergent evolution. 2. Result of divergent evolution.
Example: Thorn in Bougainvillea and tendril in Example: Limbs of man, whale, bats, etc.
Passifl ora.

Q7. What do you understand about the basic structure of organism?
Ans. The basic structure of diff erent organism shows that few parts of specifi c organ structure are
same, but may vary in their functions.

Q8. From where does scientists gather the evidences for evolution process?
Ans. The records of fossils, homologous and analogous organs, and vestigial organs provide evidences to
predict the evolution process.

Q9. Thorn of Bougainvillea and tendril of Passifl ora are referred to as homologous organs. Why?
Ans. The thorn and tendril are modifi cation of leaf, thus same in structure, but diff erent in functions, i.e.
thorns protect the plant while tendril provides support during climbing.
Q10. Feathers of birds are meant for fl ight which are the modifi cations of epidermal hair. State
their basic and primary function.
Ans. Feathers are modifi cations of body hair. Their primary function is to keep the body of animal warm.

COMPETENCY BASED QUESTIONS

Multiple Choice Questions

Q1. Observe the fi gure and answer the question.

(a) The skeletal structures are of the limbs of mammals.
(b) The skeletal structures are diff erent in origin.
(c) The skeletal structures are not clear to me.
(d) The skeletal structures are of animals and birds.

Q2. Observe the fi gure and answer the question.
(a) Fig. (a) is potato plant and shows tubers.

(b) Fig. (b) is potato plant and shows tubers.
(c) Fig. (a) and (b) are sweet potato plants.
(d) Fig. (a) is sweet potato plant and (b) potato plant.

Q3. The major diff erence in structure (anatomical) of
a bat wing (mammal) and dragon fl y (insect) is
(a) bat wing is large and dragon fl y wing is small.
(b) bat wing has bones and dragon fl y wing lacks it. (a) (b)
(c) bat wing is used for hanging from tree and dragon fl y wing is used for fl ying.

(d) none of the above explanation is correct.

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