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प्रश्न
Human tailbone is a vestigial organ. Explain.
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उत्तर
The vestigial organ is the remains of a structure that was functional in some ancestors but is no longer functional in the organisms.
In humans, many vestigial structures show a relationship to other mammals including the primates. Ancestors of human were having well-developed tailbone as their adaptation was arboreal. But gradually humans got adapted to the terrestrial habitat. So, their human tailbone is reduced (vestigial).
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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
Write the similarity between the wing of a butterfly and the wing of a bat. What do you infer from the above with reference to evolution?
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.
Which of the following is a correct set of homologous organs?
(a) Forelimbs of frog, bird and lizard
(b) Spine of cactus and thorn of bougainvillea
(c) Wings of bat and wings of butterfly
(d) Wings of a bird and wings of a bat
Four students A, B, C and D reported the following set of organs to be homologous. Who is correct ?
(A) Wings of a bat and a butterfly
(B) Wings of a pigeon and a bat
(C) Wings of a pigeon and a butterfly
(D) Forelimbs of cow, a duck and a lizard
Which one of the following pairs of vegetables is an example of homologous structures?
(A) Potato and sweet potato
(B) Carrot and radish
(C) Carrot and tomato
(D) Tomato and radish
Find out from newspapers and popular science articles any new fossil discoveries or controversies about evolution.
Enlist any four sequential evolutionary names of human ancestors.
Name the scientists who Discovered the fossil of Australopithecus
What are homologous organs?
How do homologous organs help in providing evidence for organic evolution?
Select and write analogous structures from the list given below :
1) Wings of butterfly and birds
2) Vertebrate hearts
3) Tendrils of Bougainvillea and Cucurbita
4) Tubers of sweet potato and potato
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
Wing of an insect and forelimb of a bird are :
(a) analogous organs
(b) analeptic organs
(c) homologous
(d) homophobic organs
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.
Long answer question.
Would you consider wings of butterfly and bat as homologous or analogous and why?
Similarities in the initial stages indicate the _______ evidence.
Find an odd one out.
I am a connecting link between reptiles and mammals. Who am I?
Appendix : vestigial organ : : Peripatus : ____________
Match the following.
| Column A | Column B |
| 1) Morphological evidences | a) Tail-bone or wisdom teeth |
| 2) Paleontological evidences | b) Leaf venation |
| c) Fossils |
Complete the flowchart.
Define the evidence of evolution shown in the figure.
Observe the given images and answer the following questions.
- Which evolutionary evidence does it indicate?
- What does it prove?
- State another example of evolutionary evidence.
The degenerated and non-functional organs found in an organism are called ______.
Where is carbon dating used?
Evolution has exhibited a greater stability of molecular structure when compared with morphological structures. Comment on the statement and justify your opinion.
Homologous organs are:
How do we compute the age of a fossil?
Explain divergent evolution in detail. What is the driving force behind it?
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.
Complete the following diagram:
What is the function of the appendix of our digestive system?
Find odd one out:
Write down the difference between homologous and analogous organs.
Complete the following conceptual picture:
Define Palaeontology.
Pick the odd man out:
