Taxes and Kineses

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Taxes and Kineses
2014-03-02 14:47:16
Biology Taxes Kineses camturnbull

AQA BIOL5 Taxis and Kinesis
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  1. How can organisms increase their chances of survival?
    By responding to changes in their environment
  2. Define: Taxes
    The movement towards or away from a stimulus
  3. Give an advantage of taxes
    It may increase the chances of survival of an organism, driving it to move away from a source of danger or towards a food source
  4. Give an example of taxes
    • Earthworms move away from light 
    • This is known as negative phototaxis 
    • This movement increases their chances of survival as it takes them into the soil where they can conserve water and avoid predators
  5. Define: Kinesis
    An increased rate of movement or rate of turning in response to a stimulus
  6. What does Kinesis depend on?
    • The rate of kinesis depends on the stimulus intensity
    • The more unfavourable the stimulus, the greater the rate
    • This continues until favourable conditions are reached
  7. In which direction does an organism move during Kinesis?
    • Any direction
    • Kinesis is non directional
  8. Define: Tropism
    A growth response to a directional stimulus
  9. Give an example of a tropism
    • Plant shoots grow towards the light so they can photosynthesise (positive phototropism)
    • Plant roots grow away from the light (negative phototropism) and towards gravity (positive geotropism) and water (positive hydrotropism)