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प्रश्न
What do you mean by vestigial structures? Name four vestigial organs found in man.
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उत्तर
1. Ill developed structures or structures which are of no use are sometimes found in both plants and animals. They are referred to as vestigial organs. The same organ may be functional in one organism but vestigial in another.
2. Vermiform appendix of man is one such organ. The reason could be that human ancestors were eating uncooked food with considerable amount of cellulose in it. The normal function of caecum and appendix
in mammals is the digestion of cellulose.
3. Man shows a number of other vestigial organs. About 100 have been named. A few examples are ear muscles, wisdom teeth, plica semilunaris (representing nictitating membrane of the eye), coccyx (reduced tail) etc.
4. In plants, the scale like leaves on the Indian pipe, a plant which has lost its chlorophyll and became saprophytic in nature, is vestigial.
5. There are certain flowers in which stamens do not bear anthers.
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संबंधित प्रश्न
Give two examples of vestigial organs in human beings and plants.
(a) Select the analogous structures from the combination given below:
(i) Forelimbs of whales and bats
(ii) Eyes of octopus and mammals
(iii) Tuber of sweet potato and potato
(iv) Tuber of Bougainvillea and tendrils of Cucurbita
(b) State the kind of evolution they represent
Given below is the list of vegetables available in the market. Select from these the two vegetables having homologous structures:
Potato, sweet potato, ginger, radish, tomato, carrot, okra (Lady’s finger)
(A) Potato and sweet potato
(B) Radish and carrot
(C) Okra and sweet potato
(D) Potato and tomato
Four students P, Q, R and S differently reported the following set of organs to be analogous :
P. Forelimb of a frog and forelimb of a lizard
Q. Forelimb of a bird and forelimb of a human
R. Wings of a parrot and wings of a butterfly
S. Wings of a bird and wings of a bat
The two students who have reported correctly are :
(A) P and Q
(B) Q and R
(C) R and S
(D) P and S
Enlist any four sequential evolutionary names of human ancestors.
Wing of an insect and forelimb of a bird are :
(a) analogous organs
(b) analeptic organs
(c) homologous
(d) homophobic organs
Some dinosaurs had feathers although they could not fly birds have feathers that help them to fly. In the context of evolution, this means that ______
There are five animals A, B, C, D and E. The animal A uses its modified forelimbs for flying. The animal B uses its forelimbs for running whereas the animal C uses its forelimbs for grasping. The animal D can live on land as well as in water and uses its forelimbs to prop up the front end of its body when at rest. The animal E which respires by using spiracles and tracheae uses wings for flying but its wings are analogous to the modified forelimbs of animal A.
(a) What could the animals A, B, C, D and E be?
(b) Why are the forelimbs of animals A, B, C, D called homologous organs?
(c) What does the existence of homologous organs in animals A, B, C and D tell us about their ancestors ?
(d) Why are the modified forelimbs of animal A and the wings of animal E called analogous organs?
(e) State whether animals A and E have a common ancestor or not.
Read the following statement and justify same in your own words with the help of suitable example.
There is evidences of fatal science among chordates.
Write short notes based upon the information known to you.
Embryology
Answer the following question.
Wisdom teeth : Vestigial organs :: Lungfish : ....................
“Appearance of melanised moths post-industrialisation in England is a classic example of evolution by natural selection.” Explain.
Very short answer question:
What is vestigeal organ?
Long answer question.
Would you consider wings of butterfly and bat as homologous or analogous and why?
______ is a vestigial organ in human beings.
I am a connecting link between reptiles and mammals. Who am I?
Define the evidence of evolution shown in the figure.
What is carbon dating?
How do you differentiate homologous organs from analogous organs?
Select vestigial organs from the following.
Homologous organs and vestigial organs are examples of ______ type of evidence in evolution.
Select the correct statement.
Define vestigial organs.
Basic principles of embryonic development were pronounced by:
Evolutionary convergence is the development of:
Which of the following is used as an atmospheric pollution indicator?
Appearance of antibiotic-resistant bacteria is an example of ______.
Fossils are generally found in ______.
How do we compute the age of a living tree?
How do we compute the age of a rock?
You have studied the story of Peppermoths in England. Had the industries been removed, what impact could it have had on the moth population? Discuss.
Write down the difference between homologous and analogous organs.
Find the odd one out:
Complete the following conceptual picture:
Pick the odd man out:
Write names of some vestigial organs in the human body.
