taxes and kinesis

Question 1

what is a stimulus ?

Answer 1

• a detectable change in the environment

Question 2

what can changes in the environment be detected by ?

Answer 2

• receptors

Question 3

how do organisms increase their chance of survival ?

Answer 3

• by responding to stimuli via different response mechanisms

Question 4

what kind of responses are taxis and kinesis and what do they help with ?

Answer 4

• simple responses
• keep organisms in their favourable environment/ conditions (light, moisture, chemicals)

Question 5

what is a taxes ?

Answer 5

• a simple response
• in which an organism will move their entire body towards a favourable stimulus away from an unfavourable stimulus
  (directional stimulus)

Question 6

what is it called when organisms move towards a stimulus ?

Answer 6

positive ___taxis

Question 7

what is it called when an organisms moves away from a directional stimulus ?

Answer 7

negative ____taxis

Question 8

what kind of taxis do earthworms show and how does this increase their chance of survival ?

Answer 8

• negative phototaxis
• move away from light
• move towards darker environments
• helps avoid dehydration, predators and locate food

Question 9

what kind of taxis do bacteria show and how does that increase their chance of survival ?

Answer 9

• positive chemotaxis
• move towards certain chemicals to aid survival

Question 10

what is meant by kinesis ?

Answer 10

• when an organism changes the speed of movement and the rate it changes direction
• results in an increase in random movements

Question 11

what will happen to the movement in a favourable environment ?

Answer 11

• slow movements
• keep the organism in the favourable environment for as long as possible

Question 12

what will happen to the movement in a hostile environment ?

Answer 12

• fast, random movements
• increases the chance that the organism will return to the favourable environment quickly

Question 13

if an organism moves from a favourable environment to an area where there are harmful stimuli, what will be its kinesis response ?

Answer 13

• increase the rate it changes direction
• to return to the favourable environment quickly

Question 14

if an organism is surrounded by negative stimuli, what will be the kinesis response ?

Answer 14

• rate of turning decreases to keep it moving in a relatively straight line
• increases chance of finding a new location with favourable environments

Question 15

example of an organism that shows kinesis ?

Answer 15

• woodlice
• dont have a waterproof exoskeleton
• rate of evaporation is high
• favourable environment = damp areas
  -hostile environement = dry area