bio

• Innate behaviours


  Genetically determined, heritable, encoded in DNA, intrinsic, inflexible
• Learned behaviours


  Occur as a result of experience, non-inheritable, extrinsic, adaptable, progressive
• Orientation responses


  • Taxes - Directional movement towards/away from a stimulus
  • Kinesis - Non-directional movement in response to a stimulus
• Taxes


  Directional movement of an organism in a particular direction towards/away from an environmental stimulus
• Kinesis


  Undirectional movement of an organism in response to an external stimulus
• Taxes prefixes


  • +ve (towards)
  • -ve (away)
• Kinesis


  • Photokinesis
  • Thermokinesis
  • Geokinesis
  • Thigmokinesis
  • Hydrokinesis
  • Chemokinesis
• Klinokinesis


  Frequency of changing direction/turning is proportional to the intensity of the stimulus
• Orthokinesis


  The rate of speed of an organism is proportional to the intensity of the stimulus
• For any animal response to continue, the benefits must outweigh the disadvantages
• Taxes


  Directional movement towards/away from a stimulus
• Kinesis


  Non-directional movement in response to a stimulus
• Taxes allow the animal to avoid entering unfavourable conditions, saving energy for reproduction
• Kinesis increases the chance the animal moves into more favourable conditions
• Methods of navigation


  • Visual cues
  • Stellar
  • Solar
  • Magnetic fields
  • Chemical
  • Sonar
• Homing


  The ability of an animal to return 'home' across unfamiliar territory
• Migration


  Annual, seasonal mass movement of a population of species from one geographical region to another, to meet favourable conditions
• External migration cues


  • Photoperiod
  • Shifting seasons
  • Food/water availability
• Internal migration cues


  • Circadian rhythms
  • Internal clock
  • Fat reserves
  • Sexual maturity
• The benefits of migration must outweigh the costs to ensure survival is increased
• Favourable conditions during migration save energy, allowing more energy for reproduction
• Biological rhythms


  Rhythmic changes in activity linked to cyclical changes in the environment
• Types of biological rhythms

  • Circadian
  • Tidal
  • Annual
  • Lunar
  • Semilunar
• Biological clock


  Mechanism that allows an organism to keep track of time
• Entrainment


  Synchronisation of biological rhythms by external cues
• Endogenous rhythm


  Rhythms controlled by an internal clock and continues without any external cues
• Zeitgeber


  Environmental/external cues that entrain an organism's biological rhythms
• Exogenous rhythm


  Rhythms regulated by external environmental cues
• Free-running period


  Animals' activity pattern regulated only by their biological clock
• Phase shift


  Movement of the activity pattern backwards or forwards in free-running period
• Actogram


  Graphical representation of an organism's phases over time
• Biological clocks allow organisms to anticipate environmental changes
• The suprachiasmatic nucleus is the central clock of the brain that regulates circadian rhythms
• Light receptors in the retina transmit light information to the suprachiasmatic nucleus and pineal gland
• Melatonin secretion is inhibited by daylight and stimulated by darkness
• If the suprachiasmatic nucleus is destroyed, circadian rhythms disappear entirely
• The adaptive advantage of biological clocks is that they allow the animal to operate in synchronisation with their environment and fellow species, maximising their energy yield and reproduction