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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
What are vestigial organs?
(a) Select the homologous structures from the combinations given below:
(i) Forelimbs of whales and bats
(ii) Tuber of potato and sweet potato
(iii) Eyes of octopus and mammals
(iv) Thorns 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
Which of the following pairs of two vegetables represent the correct homologous structures?
(A) Sweet potato and potato
(B) Sweet potato and tomato
(C) Carrot and potato
(D) Radish and carrot
Differentiate between analogy and homology giving one example each of plant and animal respectively.
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.
Find out from newspapers and popular science articles any new fossil discoveries or controversies about evolution.
Attempt giving a clear definition of the term species.
Explain with an example for the given, how the following provides evidence in favor of evolution in organisms :
Analogous organs
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
The wings of a housefly and the wings of a sparrow are an example of :
(a) analogous organs
(b) vestigial organs
(c) respiratory organs
(d) homologous organs
The organs P and Q of two animals have different structures but similar functions. On the other hand, the two organs R and S of two other animals have the same basic structure but different functions.
(a) What are the organs like P and Q known as?
(b) Name the organs like P and Q. Also name the animals which have such organs.
(c) What are the organs like R and S called?
(d) Name the organs like R and S. Also name the animals which have such organs.
Explain with suitable examples importance of anatomical evidence in evolution.
Observe the picture and answer the following questions.
A) Which evidence of evolution is shown in the picture?
B) What can be proven with this proof?
C) Give one more example of evidence of evolution
_______ is a connecting link between Annelida and Arthropoda.
Complete the following chart:
With the help of diagrams, describe emasculation and bagging.
Draw a labelled diagram of T.S. of a leaf showing Kranz anatomy.
Explain any three molecular (genetic) evidences in favour of organic evolution.
Define phylogeny.
Appendix : vestigial organ : : Peripatus : ____________
Define the evidence of evolution shown in the figure.
Which evidence of evolution is shown in the given picture? Explain the importance of this evidence.
Explain any five types of evidence that support the theory of evolution.
A human hand, a front leg of a cat, a front flipper of a whale and a bat’s wing look dissimilar and adapted for different functions. What is the name given to these organs?
How do you differentiate homologous organs from analogous organs?
Study of fossils is ______.
Which is not a vestigial organ in a man?
Give an example for convergent evolution and identify the features towards which they are converging.
Complete the following diagram:
I am the connecting link of annelida and arthropoda. What is my name?
Give a scientific reason.
Morphological evidences suggest that dog, sheep and wolf have a common origin.
What is the function of the appendix of our digestive system?
As shown in figure below some organisms that share a common ancestor have features that have different functions, but similar structures.
These are known as ______. Give example.
Write a note on the significance of Palaeontology.
