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प्रश्न
Answer the following question:
What are homologous structures? Give an example. Is it necessary that homologous structures always have a common ancestor? Justify your answer.
उत्तर
Homologous organs:
These are organs that are similar in origin but perform different functions. For example, the forelimbs of humans and the wings of birds perform different functions, but their skeletal structures are similar.
Yes, homology indicates common ancestry. Homologous organs follow the same basic plan of the organisation during their development but in the adult condition, these organs are modified to perform different functions as an adaptation to different environments.
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संबंधित प्रश्न
Select two pairs from the following which exhibit divergent evolution. Give reasons for your answer.
(i) Forelimbs of cheetah and mammals
(ii) Flippers of dolphins and penguins
(iii) Wings of butterflies and birds
(iv) Forelimbs of whales and mammals
State a reason for the increased population of dark coloured moths coinciding with the loss of lichens (on tree barks) during industrialization period in England.
You have potato, carrot, radish, sweet potato, tomato and ginger bought from the market in your jute bag. Identify two vegetables to represent the correct homologous structures.
(A) Potato and tomato
(B) Carrot and tomato
(C) Potato and sweet potato
(D) Carrot and radish
Define fossil.
The decaying process of C-14 occurs continuously in dead organisms only.
- Define vestigial organs.
- Write names of any two vestigial organs in the human body.
- Write name of those animals in which these vestigial organs are functional.
Give an example for convergent evolution and identify the features towards which they are converging.
How do we compute the age of a fossil?
What is the function of the appendix of our digestive system?
Give examples of homologous organs and analogous organs in plants.
