.1 Stimuli

• Kinesis:

  Non-directional movement in response to a stimuli
• Taxis:

  WL demonstrate negative phototaxis ( moving away from a light source ) More favourable as they are less likely to be eaten or dry out They stay in dark and damp conditions
• Simple organisms such as woodlice and maggots have simple responses to keep them in favourable conditions

  Small more mobile organisms are vulnerable to being eaten (predation) and drying out (dessication)
• Choice Chamber Experiment: Areas with different conditions so organisms can chose favoured area
• Reflex

  rapid reaction under one second

  automatic and involuntary

  cannot stop it

  short-lived

  don’t require conscious thought
• Controlled by a simple neurone pathway, localised in the part of the body where the reflex occurs

  Starts with the receptor, detects the stimuli/change in stimuli to respond to, turns a physical change into an electrical signal

  Passed onto the sensory neurone Carries the signal into the spinal cord where it reaches a co-ordinator

  A co-ordinator is an intermediate neurone that carries a signal to a motor neurone Brings signal to effector e.g muscle