1/6
Looks like no tags are added yet.
Name | Mastery | Learn | Test | Matching | Spaced | Call with Kai |
|---|
No analytics yet
Send a link to your students to track their progress
stimulus
detectable change in environment
Why is it important that organisms can respond to stimuli?
Organisms increase their chance of survival by responding to stimuli. (i.e. through different response mechanisms: taxes, kinesis)
taxes
directional response
organism moves towards / away from directional stimulus (towards → positive taxis) (away → negative taxis)
benefits of negative phototaxis
avoids predators
in soil e.g. avoids dehydration, locate food
kinesis
non directional response
speed of movement or rate of direction changes in response to a non directional stimulus
depends on intensity of stimulus
protective effect of a simple reflex
rapid: only 3 neurones and few synapses
autonomic: doesn’t involve brain, doesn’t need to be learnt
protects from stimuli e.g. escape predators, prevent damage to tissues
kinesis example
area with beneficial stimuli → area of harmful stimuli: kinesis response increases
organism increases rate it changes direction (turning) in order to find favourable environment
if surrounded by negative stimuli: rate of turning decreases to keep it moving in a straight line to increase the chances of it finding a new location with favourable conditions.