Transcript Movement - JLooby Biology

Coordination and Response
in Plants and Animals
Introduction
Response of Plants and Animals
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Syllabus Objectives
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Define ‘stimulus’ and ‘response’
Describe the response of:
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Green plants to unilateral stimuli of light and gravity
Invertebrates to variations in light intensities,
temperature and moisture
Explain why the response to stimuli is important
for the survival of organisms
Stimuli and response
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Plants and Animals receive information about
changes in conditions both inside and outside
their bodies
Any information to which an organism reacts
is known as a stimulus because it stimulates
the organism to make a response
Stimuli and Response
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A stimulus could be an external event
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Change in direction of light
Change in light intensity or
Change in temperature
Internal events include
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Arrival of food in the stomach
Changes in blood glucose level
Entry of foreign organisms in the body or change
in water content of cells
Stimuli and Response
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Some changes can be
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positive or advantageous,
unfavourable or harmful,
unimportant
Question
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Can you list 2 favourable stimuli, 2 unfavourable
stimuli and 2 that are unimportant
Stimuli and Response
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Response can be through
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the movement of the whole animal
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the movement of part of the animal
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E.g. earthworm moving away from light
E.g. closing of the pupil of the eye to bright light
Response in plants
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Movement through part of the organism
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E.g. tip of a plant grows in the direction of light
Response and Stimuli
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Can you list 3 examples of what a response
to an internal stimulus could be?
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Secretion of enzymes in response to food
Production of antibodies in response to foreign
organisms
Secretion of hormones in response to changes in
blood glucose levels
An increase in heart rate in response to an
increase in CO2 content of the blood
The Importance of response
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Response to stimuli is important for the
survival of organisms
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Shoots of green plants grow toward the light so
that they could make food
Roots grow in the direction of gravity. They grow
towards moisture and provides stability for the
plant
Animals avoid unsuitable conditions by moving to
suitable ones
The Importance of response
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Hunted animals avoid predators when they see,
hear or smell their approach
A male moth is attracted to a female moth by being
able to detect and respond to chemical signals
released by the female
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This response ensures that reproduction takes place and
the species survives
The Sensitive plant (Mimosa pudica) folds its leaves
quickly when touched. This makes it more difficult
for animals who eat them to see them.
Practice Investigative Questions
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How do the shoots of seedlings respond to receiving
light from one direction only?
Will roots grow downwards regardless of how the
rest of the seed or seedling is positioned?
How do millipedes, earthworms and/or woodlice
respond to variations in light intensities?
How do small invertebrates respond to temperature
changes?
How do small invertebrates respond to different
levels of moisture?