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Organisms and Populations — BIOLOGY STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceBIOLOGYOrganisms and Populations3 Marks
Question
Explain by taking three different examples, how certain organisms pull through the adverse conditions, when unable to migrate under stressful period.
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Answer

Organisms overcome the stressful conditions that are of short duration in the following ways:
  1. The animals migrate, i.e. they move away from the stressful habitat to a more hospitable area and return to their habitat when the stressful period is over, e.g. Birds from Siberia and other cold countries migrate to Bharatpur Sanctuary in Rajasthan.
  2. Animals which cannot migrate, suspend/ reduce their metabolic activity and avoid stress by escaping in time.
  • They show hiberation, i.e., escaping in time during winters, e.g. bears and frogs.
  • They may go into aestivation, i.e. escaping in time to avoid summer-related problems, e.g. snails and fish.
  • Zooplanktons enter diapause, a state of suspended development.
  1. In bacteria, fungi and lower groups of plants, various types of thick-walled spores are formed; they germinate under suitable conditions.

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