Taxes and Kinesis

Question 1

Simple Responses to stimuli – animals.
Organisms increase their chance of ________by responding to changes in their ________ environment.
Simple mobile organisms eg woodlice, have simple responses to keep them in a ___________environment. Their response can be either ______(a _____) or ______(a ______).

Answer 1

Organisms increase their chance of survival by responding to changes in their external environment.
Simple mobile organisms eg woodlice, have simple responses to keep them in a favourable environment. Their response can be either tactic (a taxis) or Kinetic (a kinesis).

Question 2

Tactic response (taxis)

This is the ________movement of the entire organism in response to a directional stimulus. The direction of the stimulus and/or the _______in stimulus intensity affects the movement. Such simple behaviours are _______(genetically programmed

Answer 2

This is the directional movement of the entire organism in response to a directional stimulus. The direction of the stimulus and/or the gradient in stimulus intensity affects the movement. Such simple behaviours are innate (genetically programmed

Question 3

Examples of taxes
Single celled algae- as algae are _____________they move towards the light (__________phototactic)

Answer 3

Single celled algae- as algae are photosynthetic they move towards the light (positively phototactic)

Question 4

Example of taxes
Earthworms move away from the light (________ phototaxis).
This helps them ________as they then move into the soil, which helps them conserve _____, find ____and avoid ___________

Answer 4

Earthworms move away from the light (negative phototaxis).
This helps them survive as they then move into the soil, which helps them conserve water, find food and avoid predators

Question 5

Examples of taxes
Some bacteria move towards areas where _______ is more _____________( positive chemotaxis)

Answer 5

Some bacteria move towards areas where glucose is more concentrated ( positive chemotaxis)

Question 6

Kinetic response (kinesis)
This is a ___ ____________(random) movement in response to a stimulus. The size of the stimulus affects the ______of movement and the rate of _________.
When the organism finds its __________environment it ___________it’s speed of movement and ________its rate of turning – this ensures that the organism remains in the favourable environment, so __________its chances of __________.

Answer 6

This is a non directional(random) movement in response to a stimulus. The size of the stimulus affects the speed of movement and the rate of turning.
When the organism finds its favourable environment it decreases it’s speed of movement and increases its rate of turning – this ensures that the organism remains in the favourable environment, so increasing its chances of survival.

Question 7

So where do we go from here? Context is important – are they plonked in unfavorable conditions or have they just crossed into them?

Answer 7

Exam key words – In Kinesis the direction is random, the speed can increases/decrease. Often times just ‘movement’ increases/decreases is sufficient

Taxis – when direction matters and is either towards or away from the stimuli. Kinesis directions are always random with an element of luck

Question 8

Examples of kineses

Woodlice move ____rapidly and change direction ____often in dry conditions. This increases their chance of _______by reducing their______ ____ and helps to keep them __________from predators

Answer 8

Woodlice move more rapidly and change direction less often in dry conditions. This increases their chance of survival by reducing their water loss and helps to keep them concealed from predators