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Human Evolution — Biology STD 10 — Question

ICSE BoardEnglish MediumSTD 10BiologyHuman Evolution5 Marks
Question
Briefly discuss Lamarckian Theory of Inheritance citing an appropriate example.
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Answer

  • According to the theory of inheritance of acquired characters, 'the changes in structure or function of any organ acquired during the life-time of an individual in response to changes in the surrounding environment are inherited by offspring and keep on adding over a period of time'.
  • This theory states that characters are acquired by animals in two ways:

    • - Effects of environment
    - Use and disuse of body parts
  • For example, the long neck of giraffe is explained by Lamarck on the same principle. Giraffe, which lived in the dry and arid deserts of Africa, tried to reach the foliage high up on the trees to eat them as there was no vegetation on the ground. In the process, its neck and forelegs got stretched a bit and this was inherited by the next generation. Then, in the next generation, the same efforts continued. Gradually, through many successive generations, we got a giraffe having a long neck and long forelegs.

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