Taxis vs Kinesis Animal Behavior Kinesis nondirectional response
Taxis vs. Kinesis Animal Behavior
Kinesis § non-directional response – doesn’t cause the animal to go in a specific direction §a change in the speed of movement
Kinesis examples § In times of increased humidity, the animal moves slower § Pill bugs move around when you lift up their rock § In dry environments, wood lice will move around until they find a damp environment (though in random directions until they find it) § When light is shone on cockroaches, they move about in random scattering movements
Taxis § movement directly toward (positive) or away from (negative) a stimulus
Taxis examples § phototaxis=light; geotaxis=gravity; thigmotaxis=contact with other objects § Fruit flies are attracted to bright light and food (rotting and fermenting so they can lay their eggs)
The Pill Bug Experiment § Setup: 5 pill bugs in dry petri dish, 5 pill bugs in wet petri with a little door or bridge between them. Observe their movements and where they are after 10 minutes.
Results § When the pill bugs are on the dry side, they are moving about very quickly and randomly, because they are unhappy and don’t like that environment § The pill bugs on the wet side move very slowly and not as much § The pill bug from the dry side may encounter the wet side during its random movements, and it may slow down and stay there.
Taxis or Kinesis!? !
Kinesis They are not moving TOWARDS the wet environment, they are RANDOMLY moving about The state of the environment (dry) is influencing the way in which the pill bugs move
- Slides: 10