Compare plants and animals regarding their response to stimuli
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Answer:
The ability of an organism to detect changes and make appropriate responses is called sensitivity. Anything to which an organism responds and reacts is called a stimulus. In animals the responses are quicker and more obvious. Unicellular animals respond to stimuli either by moving towards them or away from them.
In multicellular animals, the process of responding to stimuli is different. The responses occur within seconds, but through a complex network of communication which involves several life processes like movement, locomotion, transport, respiration, etc. For example, when you step out in bright sunlight, you partly close your eyes to keep out the bright light. You may start sweating as the temperature rises. These are coordinated responses to stimuli.
Response and coordination in animals involve the sense organs, nervous system and chemical messengers called hormones.
Plants also react to specific environmental conditions. However, they have no nervous system and their responses are in the form of slow modified growth or movements called turgor movements, caused due to the distension (swelling) of cells. Let us first examine the phenomena of response and coordination in plants.