Orientation Responses Animal

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

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 Stimulus positive taxis towards the stimulus negative taxis away from the stimulus

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

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

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

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

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

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

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

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

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

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