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प्रश्न
Explain the occurrence of vestigial organs on the basis of Lamarck's theory of use and disuse.
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उत्तर
Organs which are found in reduced or rudimentary condition and do not perform any function in the possessor are called vestigial organs or non-functional organs. They help in understanding the history of evolution and continuity of life.
- Wisdom teeth: They are the last molars which appear last at the age of 17-20 years.
- Vermiform appendix: It projects from the blind end of the caecum and is a functionless organ in humans. It is helpful in herbivorous mammals.
- Pinna: It is the lobe-like part of the external ear which humans cannot move as in other mammals. As it is poorly developed, it is a vestigial organ.
संबंधित प्रश्न
Write a short note based on the information known to you.
Lamarckism
Given alongside are two figures (A and B) showing a phenomenon that was first observed in Manchester before and after the year 1850.
Answer the following:
Briefly mention why the changes shown in the two figures appeared.
Given alongside are two figures (A and B) showing a phenomenon that was first observed in Manchester before and after the year 1850.
Answer the following:
The following phenomenon provides a classical explanation of a scientific theory given by a certain scientist.
(i) Name and explain the said theory.
(ii) Give the name of the scientist who gave this theory.
Theory of evolution : Darwin : : ____________ : Lamarck
The characters developed by the animals during their life time, in response to the environmental changes are called ______.
The degenerated wing of a kiwi is an acquired character. Why is it an acquired character?
Observe the figure given below and answer the questions that follow:
- What is the figure depicting?
- What was the reason that the giraffe stretched their neck and forelimbs?
- What is the name of the theory that is being depicted in the figure?
- Who explained the theory?
- What is the conclusion of this theory?
According to the postulate on the 'Formation of New Organs', a new organ develops in response to which factor?
According to the 'Use and Disuse of Organs' principle, what is the effect of continuous disuse of an organ?
In the evolution of the horse, the shift from being flat-footed to running on hooves corresponds to which specific change?
