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Responses To Abiotic Factors - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #NEET

Quick Facts

  • Responses to Abiotic Factors: Regulate & Conform, Responses to Abiotic Factors: Migrate & Suspend is considered one of the most asked concept.

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Responses to Abiotic Factors: Regulate & Conform

What is hemostasis:

  • Homeostasis is any self-regulating process by which an organism tends to maintain stability while adjusting to conditions that are best for its survival.
  • Body temperature control in humans is one of the examples of homeostasis.

Regulate:

  • Some organisms are able to maintain homeostasis by physiological (sometimes behavioural also) means which ensures constant body temperature, constant osmotic concentration, etc.
  • All birds and mammals, and a very few lower vertebrate and invertebrate species are indeed capable of such regulation (thermoregulation and osmoregulation).
  • The mechanisms used by most mammals to regulate their body temperature are similar to the ones that we humans use. 
  • We maintain a constant body temperature of  37oC. 
  • In summer, when outside temperature is more than our body temperature, we sweat profusely.
  • The resulting evaporative cooling, similar to what happens with a desert cooler in operation, brings down the body temperature. 
  • In winter when the temperature is much lower than 37oC, we start to shiver, a kind of exercise which produces heat and raises the body temperature. 
  • Plants, on the other hand, do not have such mechanisms to maintain internal temperatures.

Conform:

  • 99 percent of animals and nearly all plants cannot maintain a constant internal environment.
  • Their body temperature changes with the ambient temperature. 
  • In aquatic animals, the osmotic concentration of the body fluids change with that of the ambient water osmotic concentration. 
  • These animals and plants are simply conformers. 
  • These conformers had not evolved to become regulators because thermoregulation is energetically expensive for many organisms. 
  • This is particularly true for small animals like shrews and hummingbirds. 
  • Heat loss or heat gain is a function of surface area. 
  • Since small animals have a larger surface area relative to their volume, they tend to lose body heat very fast when it is cold outside; then they have to expend much energy to generate body heat through metabolism. 
  • This is the main reason why very small animals are rarely found in polar regions. 
     
Responses to Abiotic Factors: Migrate & Suspend

Migrate:

  • The organism can move away temporarily from the stressful habitat to a more hospitable area and return when the stressful period is over.  
  • Many animals, particularly birds, during winter undertake long-distance migrations to more hospitable areas. 
  • Every winter the famous Keoladeo National Park (Bharatpur) in Rajasthan hosts thousands of migratory birds coming from Siberia and other extremely cold northern regions.

Suspend:

  • In bacteria, fungi and lower plants, various kinds of thick walled spores are formed which help them to survive unfavourable conditions – these germinate on availability of suitable environment.
  • In higher plants, seeds and some other vegetative reproductive structures serve as means to tide over periods of stress besides helping in dispersal – they germinate to form new plants under favourable moisture and temperature conditions. 
  • They do so by reducing their metabolic activity and going into a date of ‘dormancy’.
  • In animals, the organism, if unable to migrate, might avoid the stress by escaping in time. 
  • The familiar case of bears going into hibernation during winter is an example of escape in time. 
  • Some snails and fish go into aestivation to avoid summer–related problems-heat and desiccation. 
  • Under unfavourable conditions many zooplankton species in lakes and ponds are known to enter diapause, a stage of suspended development.
     

 

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