6a: Stimuli And Responses

Question 1

responding to changes in environment

Answer 1

by responding to changes in their environment, organisms increase their chance of survival .Those organisms that survive have a greater chance of raising offspring + of passing their alleles to the next generation. There is always , therefore , a selection pressure favouring organisms with more appropriate responses.

Question 2

stimulus

Answer 2

detectable CHANGE in the internal/ external environment of an organism that leads to a response

Question 3

receptor

Answer 3

detects stimulus , SPECIFIC to one type of stimulus

Question 4

coordinator

Answer 4

FORMULATES a suitable response to a stimulus e.g. nervous system / hormonal system

Question 5

effector

Answer 5

PRODUCES response to a stimulus e.g. muscles/ glands

Question 6

Response

Answer 6

This response may be at the molecular level or involve the behaviour of a whole organism