Communication: detecting stimuli

Question 1

explain that the response to a stimulus involves: 
stimulus
receptor
messenger
response

Answer 1

In order that a stimulus may produce a response, a receptor must detect the stimulus. A message must then be passed to a messenger, which may be a nerve or a hormone. The messenger then passes information to an effector, which may be a gland or a muscle, which responds to the information.

Question 2

identify data sources, gather and process information from secondary sources to identify the range of senses involved in communication

Answer 2

Identify the data sources and determine the appropriate ways in which each aspect may be researched.
Try to gather information from a range of resources, including popular scientific journals, digital technologies and the Internet. Focus on collecting simple descriptions of the senses involved in communication. Then choose a range of senses that are used as a form of communication in humans and other animals.
Once you have collected it, summarise the information. The table below is a model for you to follow.
Senses
Human examples
Other animal examples
sight (visual)
facial expression signal emotions including aggression
bioluminescence in fireflies to attract mates, female chimpanzees have a coloured rump to show when they are ready for mating, Blue-ringed octopus signal an intention to attack by glowing blue rings on their bodies.
smell (olfactory)
not so important in humans, human females may change their menstrual cycle because of olfactory information
animals release pheromones to make their presence known; male mice will mate immediately they smell a receptive female.
hearing (auditory)
language used extensively to convey information, used as a warning signal.
crickets use sound as a warning and to attract mates, some moths can hear the ultrasonic calls of bats and can avoid being eaten, frogs use sound for mating calls, dolphins use echolocation.
touch (tactile)
used in group bonding and in mating. Also used aggressively
seagull chicks get their mothers to release food by pecking on their beaks. Bees dance to communicate the location of food.
taste

some butterflies such as the Monarch butterfly have a bitter taste to communicate that they are poisonous

Question 3

identify the role of receptors in detecting stimuli

Answer 3

A stimulus is a change in the environment. Examples of stimuli include light, sound, temperature, pressure, pain and certain chemicals.
A receptor is a specialised cell that detects a stimulus. As a result a nerve impulse may be generated or a hormone produced. There is a range of receptor cells adapted to detecting specific stimuli, e.g. rods and cones in the eye. Sometimes receptors are distributed all over the body, such as touch receptors in the skin. In other cases, particular receptors are concentrated in an organ, such as the eye, or an endocrine gland such as the adrenal gland.