4.2
energy flow
Essential Idea: Ecosystems require a continuous supply of energy to fuel life processes and to replace energy lost as heat.
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Nature of Science: Use theories to explain natural phenomena: the concept of energy flow explains the limited length of food chains.
UNDERSTANDINGS:
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Most ecosystems rely on a supply of energy from sunlight.
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Light energy is converted to chemical energy in carbon compounds by photosynthesis.
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Chemical energy in carbon compounds flows through food chains by means of feeding.
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Energy released from carbon compounds by respiration is used in living organisms and converted to heat.
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Living organisms cannot convert heat to other forms of energy.
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Heat is lost from ecosystems.
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Energy losses between trophic levels restrict the length of food chains and the biomass of higher trophic levels.
APPLICATIONS & SKILLS:
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Skill: Quantitative representations of energy flow using pyramids of energy.
RESOURCES: