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Evolution

Short Answer Type

71. Describe De Vries Mutation theory.

De Vries Mutation Theory Hugo de Vries (1848-1935) was a Dutch Botanist. He performed experiments on the Evening Primrose (Oenothera lamarckiana).

According to this theory, new species arise suddenly showing abrupt deviations in characters from the normal forms. Thus evolution is not a slow and gradual process but a sudden discontinuous and process. He believed that mutation caused speciation and hence called it saltation (single step large mutation)

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72. What is the main difference between Darwin's theory of natural selection and De Vries mutation theory ?

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73. What is competition in nature ? How does it affect the plant and animal life ? Mention some examples.

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Long Answer Type

74. Where did Darwin err in his theory of the “Origin of Species” through natural selection ?

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Short Answer Type

75. List three mechanisms by which variant genotypes can be produced in nature.

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76. Why is the frequency of sickle cell anaemia more in the malaria prone areas ?

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Long Answer Type

77. What is industrial melanism ?

Explain how natural selection has worked on population of peppered moth in industrial area of England.

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Short Answer Type

78. What observations is natural selection based on ?

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79. How is artificial selection different from natural selection ?

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80. Polyploidy can also lead to the formation of a new species very rapidly. Explain.

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