Survival Stratagies

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Survival Stratagies
2012-10-01 12:44:15

Advanced Higher Biology - Unit Two - Survival Stratagies
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  1. What is a regulator?
    A regulator is an organism that uses homeostatic control to maintain a constant internal environment despite changes in the environment
  2. Give an advantage and disadvantage of being a regulator
    • Advantage - can occupy a wide range of habitats
    • Disadvantage - energy costs are much greater for warmth and active transport of ions to maintain osmotic conditions
  3. What subcategories can regulators be split into?
    • Homeotherms
    • Osmoregulators
  4. What is a homeotherm?
    Organisms which maintain a constant body core temperature by both behavioural and physiological means eg humans, dogs
  5. What is an osmoregulator?
    An organism which maintains body fluids at a constant concentration of water and salts.  They must either accumulate or excrete salts depending on their environment eg humans, salmon, eels
  6. What is a conformer?
    A conformer is an organism which adopts internal conditions which fluctuate directly with the surroundings
  7. What is an advantage and disadvantage of being a conformer?
    • Advantage - energy costs are much lower.  A crocodile only requires a sixth of a similar sized human being.
    • Disadvantage - have smaller tolerance limits so have restricted habitat range.  Must stay in environment with conditions which suit life eg not many reptiles in Scotland compared to South Europe.
  8. What are the subcategories can conformers be split into?
    • Poikilotherms
    • Osmoconformers
  9. What is a poikilotherm?
    Animals whose body temperature varies with the surrounding environment.  Most are ectotherms (absorb heat from their surroundings) eg spider, crocodile, snake
  10. What is an osmoconformer?
    An organism whose body fluids are isotonic to the surrounding medium.  No osmotic gain or loss eg jellyfish and most other marine invertebrates
  11. What is the difference between predictive and consequential dormancy?
    Predictive dormancy occurs before the adverse conditions whereas consequential dormancy occurs immediately as a direct result of changing environmental conditions
  12. Name and describe the different types of dormancy?
    • Resting spores - dormancy in spores of fungi and bacteria.  Occurs because of drought or low temperature
    • Diapause - suspended developmental stage due to low temperatures.  Occurs in insects in temperate regions eg butterflies
    • Hibernation - animals are inactive and turn off thermoregulation in response to food shortage or cold temperatures to save energy.  Occurs in hedgehogs and doormice
    • Aestivation - torpor or inactivity due to hot and/or dry conditions.  Occurs in snails, african lungfish and desert frogs