Biology / Unit 3 Bio 0612 short lesson, about 20 seconds
Energy Flows and Degrades; Matter Cycles
Captions available
The idea
Matter cycles between organisms as carbon passes from carbon dioxide to sugar and back; energy flows one way instead, degrading to heat.
In practice
A carbon atom fixed into sugar is respired and fixed again many times, but its light energy is gone for good.
Where people slip
Students often expect energy to cycle back to producers like carbon does, instead of dissipating as heat each transfer.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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