Stimulus and response Flashcards
Define a stimulus
A stimulus (plural: stimuli) is anything that causes a reaction in an organism or in any of its parts
Define a response
A response is the activity of a cell or organism as a result of a stimulus.
Examples of animal stimuli
Animal stimuli include hearing a loud noise, seeing a pleasant sight, smelling nice perfume or feeling pain or hunger.
Examples of animal responses
Animal responses include movement, production of enzymes or hormones and feeding.
Give examples of structures required by organisms in order to allow response (4). Indicate whether these are present or absent in plants or animals.
The structures needed by organisms in order to allow them to respond include:
1. A chemical or hormonal system (present in plants and animals)
- A nerve and sense organ system (only found in animals)
- A method of movement, which includes growth along with muscular and skeletal systems (a muscular and skeletal system is only found in animals)
- A defence or immune system.
What system do plants not possess that animals do?
Plants do not possess nervous systems.
What do plants depend on for their responses?
they depend on chemical coordination for their responses
What is different about chemical coordination and nervous coordination?
Chemical coordination is much slower than nervous coordination.
What do plant responses often involve?
Plant responses often involve growth and changes in growth.
What do growth and changes in growth responses cause?
These responses cause plants to move, but their movement is much slower than that of animals.
Give examples of plant stimuli
Plant stimuli include light, gravity, water and chemicals.
Give some examples of plant responses
Plant responses include growth, flowering, fruit formation and production of plant enzymes.
