Trophic level
A feeding level in a food chain: producers (plants and algae), primary consumers (herbivores), secondary consumers (carnivores that eat herbivores), and so on. Decomposers break down dead matter.
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Analogy
Floors in a building, each living off the floor below.
In practice
A grass, grasshopper, frog, snake, hawk chain has five levels.
Practice
Flashcards
- What are decomposers?Organisms such as fungi and bacteria that break down dead matter and return nutrients to the soil.
- Why do food chains have few levels?Only about 10 percent of energy passes to each next level, so little is left.
Interview questions
- Explain why energy transfer limits the length of food chains and the number of top predators.
- About 10 percent passes on
- Losses as heat and uneaten parts
- Little energy left at top
- Fewer, larger predators
Questions people ask
What is the difference between a food chain and a food web?
A food chain is a single line of who eats whom. A food web joins many chains, showing that most animals eat several foods and are eaten by several predators. Webs are more realistic and show how losing one species can affect many others.
What do decomposers do in an ecosystem?
Decomposers, mainly fungi and bacteria, break down dead plants, animals and waste. They release nutrients such as nitrogen and phosphorus back into the soil, where plants can take them up again. Without them, nutrients would stay locked in dead matter and life would run out of materials.