Responses to Stimuli: Survival & Response Flashcards
what is a stimulus?
a stimulus is a detectable change in the internal or external environment of an organism that leads to a response in the organism
what are stimuli detected by?
receptors (specific to one type of stimulus)
what is a co-ordinator?
formulates a suitable response to a stimulus
what produces a response?
an effector
what are the chemicals used for communications/responses in large, multicellular organisms?
hormones
as well as hormonal communications, what more rapid means of communication do animals have?
the nervous system
in an animals nervous system, what is each different receptor and effector linked to?
a central co-ordinator
summarise the sequence of events involving either chemical control or nerve cells
Stimulus → Receptor → Co-ordinator → Effector → Response
what increases the chances of survival for an organism?
the ability to respond to a stimuli
what do the organisms that survive have a greater chance of doing?
raising offspring and passing on their alleles to the next generation
what is always favouring organisms with more appropriate responses?
a selection pressure
