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प्रश्न
Give two examples of vestigial organs in human beings and plants.
Give some examples of vestigial organs.
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उत्तर
Vestigial organs are remains of a structure that were functional in some ancestor but is no longer functional in present body.
Some examples of such organs in humans are:
(a) Appendix: The appendix is a small projection of the side of the large intestine near the cecum. It looks kind of like a tail and is found near where the small and large intestines meet. No one knows the actual original function of the appendix.
(b) The tail bone: Attached to the bottom of the sacrum is the coccyx or tailbone. This small, bony projection seems to be a leftover structure of primate evolution. It is believed that human ancestors once had tails and lived in trees. The coccyx would be where the tail was attached to the skeleton.
Some examples of such organs in plants are:
(1) Sexual organs of dandelions: The common dandelion reproduces asexually through a process known as apomixis. However, they still have all of the functional parts that most flowering plants use to reproduce sexually, namely the stamen and pistil.
(2) Grass often has small, undeveloped structures that strongly resemble those of flowering plants.
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संबंधित प्रश्न
Study the following statements:-
I. Wings of birds and wings of bats are homologous organs.
II. Wings of birds and wings of insects are modified forelimbs.
III. Wings of birds and wings of insects are analogous organs.
IV. Wings of birds and forelimbs of horse are homologous organs.
The correct statements are
(A) I and II
(B) II and III
(C) III and IV
(D) I and IV
Give the importance of fossil in support of organic evolution
Differentiate between analogous and homologous structures.
Out of bacteria, spider, fish and chimpanzee, which organism has a better body design in evolutionary terms? Give reason for your answer.
The organs which perform similar functions but have different basic structure are called :
(a) asymmetric organs
(b) analogous organs
(c) homologous organs
(d) homophonic 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.
What do we call the degenerated or partially developed useless organs in living organisms? Enlist such organs in human body? How the same organs are useful in other animals?
“Appearance of melanised moths post-industrialisation in England is a classic example of evolution by natural selection.” Explain.
Draw a labelled diagram of T.S. of a leaf showing Kranz anatomy.
Choose the correct option of the following question:
Wings of Insect and Birds are examples of :
Define fossil.
The decaying process of C-14 occurs continuously in dead organisms only.
Enlist the evidences of evolution.
Which evidence of evolution is shown in the given picture? Explain the importance of this evidence.
Where is carbon dating used?
Organs having similar functions but different origin and development are known as:
The bones of forelimbs of whale, bat, cheetah and man are similar in structure, because ______.
Find odd one out:
Industrial melanism in England after 1850 is an excellent example of Natural selection. Explain how?
