14.1: Response to Stimuli

Question 1

What is a stimuli

Answer 1

A detectable change in the internal or external environment off an organism that leads to a response

Question 2

What is the importance of responding to stimuli

Answer 2

It is characteristic of life and increases the chances of survival

Animals are able to move away from predators

Organisms are able to pass on their alleles

Question 3

What is a response

Answer 3

The process that follows the detection of a stimuli

Question 4

What detect stimuli

Answer 4

Receptors

Question 5

What are receptors specific to

Answer 5

One type of stimulus

Question 6

What is the role of a coordinator

Answer 6

Coordinators formulate a suitable response to a stimulus

Question 7

What formulates a response

Answer 7

An Effector

Question 8

Where can the response be

Answer 8

At a molecular level

Involve the behaviour of an entire organism

Question 9

What are the sequence of events regarding chemical control

Answer 9

1. Stimulus
2. Receptor
3. Coordinator
4. Effector
5. Response

Question 10

What is a taxis

Answer 10

A simple response which changes the direction of an organism

Question 11

Types of taxes

Answer 11

Positive taxis = Towards the stimulus

Negative taxis = Away from the stimulus

Question 12

Example of a taxis response

Answer 12

Algae moving towards the light (Phototaxis)

Uses flagellum

Question 13

What is a kineses

Answer 13

Type of response in which the organism changes the speed at which it moves and the rate at which it changes direction

Question 14

Importance of a taxis response

Answer 14

Moving towards an important resource, for example sunlight

Aids survival

Question 15

Importance of a kinesis

Answer 15

Moving away faster from a predator

Aids survival so favourable alleles can be passed on

Question 16

Example of kinesis

Answer 16

Woodlice lose water in dry conditions, they move rapidly from a dry area to a damp area

Question 17

What is a tropism

Answer 17

A tropism is the growth of part of a plant in response to a directional stimulus

Question 18

Types of tropisms

Answer 18

Positive tropism = towards the stimulus

Negative tropism = away from the stimulus

Question 19

Examples of tropisms in plant shoots

Answer 19

Positive phototropism (toward the light)

Negative gravitropism (away from gravity)

Question 20

Example of tropisms in plant roots

Answer 20

Negative phototropism (away from the light)

Positive gravitropism (towards gravity)