Ecosystem Energy Flow
Energy flows through ecosystems from producers to consumers via food chains and webs. Understanding energy transfer helps explain the structure and limits of ecosystems and why there are fewer organisms at the top of food chains.
What You Need to Know
Key Concept Diagram
Producers (plants) capture solar energy through photosynthesis
Primary consumers (herbivores) eat plants; secondary consumers (carnivores) eat herbivores
Only about 10% of energy is transferred at each trophic level; the rest is lost as heat
Food webs show the interconnected feeding relationships in an ecosystem
Key Vocabulary
Producer
An organism (usually a plant) that makes its own food through photosynthesis
Consumer
An organism that obtains energy by eating other organisms
Trophic level
A step in a food chain; each level represents a different stage in energy transfer
Biomass
The total mass of living organisms at a particular trophic level
Knowledge Check
Select the correct answer for each question. Click "Check Answer" to see if you are right.
Question 1
Why are there usually fewer organisms at the top of a food chain than at the bottom?
Question 2
In the food chain: Grass -> Grasshopper -> Frog -> Snake, the frog is a:
Question 3
A food web differs from a food chain because it:
Key Concepts Summary
- ●Producers (plants) capture solar energy through photosynthesis
- ●Primary consumers (herbivores) eat plants; secondary consumers (carnivores) eat herbivores
- ●Only about 10% of energy is transferred at each trophic level; the rest is lost as heat
- ●Food webs show the interconnected feeding relationships in an ecosystem