Orientation Responses

1. Orientation Responses Animal

2. General • Orientation repsonses are ones where the animal positions itself or carried out specific behaviours when an environmental factor changes direction, duration or intensity • They can range from simple ones (taxes, kinesis) to changes in factors such as light, humidity or touch, to complex behaviours such as migration or homing • These responses help organisms avoid adverse conditions

3. Stimulus negative taxis positive taxis away from the stimulus towards the stimulus Taxis • Movement of the whole animal towards or away from a stimulus that is uni-directional • Movement towards the stimulus is positive • Movement away from the stimulus is negative • Tactic responses are named according to the kind of stimulus

4. Kinesis • Random movement response • Activity rate it determined by intensity of stimulus rather than direction • Neither positive nor negative • If the organisms speed is effected it is termed orthokinesis • If the organisms rate of turning is effected it is termed klinokinesis • These responses may be modified by the animals internal state

5. Migration • Regular, annual mass movements • Move from breeding area to another area where they do not breed and eventually back again • It is carefully planned • Behaviour must be inherited, and maintained by natural selection

6. Advantages • Animals remain in a favourable temperature • They grow larger • They leave more offspring • They have a constant supply of food • It may lead to the colonisation of a new area • Reduces predation/parasitism disease • Greater genetic mixing • Better breeding conditions

7. Disadvantages • They may get lost or caught in a storm • They may get eaten by a predator • They may use up too much energy in the migration, leading to exhaustion • They may starve • It’s a huge investment in energy

8. Triggers • The behavioural trigger that sets off migratory behaviour varies • Maturation – as sex organs mature and there is a need or desire to reproduce • Environmental clues – such as a drop in temperature and shortening of day length • Genetic drive – some behaviour is genetic and some learned, star patterns are learned but how to learn them is innate

9. Homing • The ability of an individual to return to the home site • This may be a hive, nest, mound, burrow etc • The home provides food, warmth shelter and protection for young • Animals have to leave the home for food and to find mates but need to be able to find it again

10. Methods of homing and Migration • Methods used to find home and for migration are often the same • Some animals use more than one method • There is a certain amount of learning involved

11. Piloting • An animal moves from one familiar landmark to another until it reaches its destination • This is used over short distances • It uses visual cues

12. Compassing • An animal can detect a compass direction and travels in a straight-line path until it reaches its destination • It can use: • Magnetic field lines • Chemical clues • Sound

13. Navigation • Involves determining one’s position relative to other locations • Two things are required for both solar and stellar navigation: • Map sense – the ability to be aware of lattitude and longitude of an area • Sense of timing – an internal clock