A food chain shows how energy passes from one living thing to the next as they eat each other. It always starts with a producer (like grass) and moves through consumers (animals) to decomposers. A food web is many food chains linked together into one bigger picture of an ecosystem. On this page you will find clear diagrams, food chain examples, the roles of producers, consumers, and decomposers, and an interactive quiz to test yourself.
What is a food chain?
A food chain is a simple model that shows who eats whom in an ecosystem, and how energy moves along the way. Every food chain begins with a producer — usually a green plant that makes its own food from sunlight through photosynthesis. Next come consumers: animals that get their energy by eating plants or other animals. Finally, decomposers break down whatever is left when plants and animals die.
The most important thing about a food chain is the direction of the arrows. An arrow always points from the food to the organism that eats it, because that is the direction the energy travels. So we write grass → grasshopper, not grasshopper → grass. If you can read the arrows correctly, you understand the food chain.
Producers, consumers, and decomposers
Every living thing in a food chain has a role. Knowing the role tells you where an organism fits and what it eats. The table below sums up the main roles with an example of each.
| Role | What it does | Examples |
|---|---|---|
| Producer | Makes its own food from sunlight (photosynthesis) | grass, algae, trees, phytoplankton |
| Primary consumer | Herbivore — eats producers (plants) | grasshopper, rabbit, deer, caterpillar |
| Secondary consumer | Eats primary consumers | frog, spider, small fish |
| Tertiary consumer | Eats secondary consumers (often a top predator) | snake, owl, hawk |
| Decomposer | Breaks down dead matter and returns nutrients to the soil | bacteria, fungi, earthworm |
Trophic levels and energy flow
Each feeding step in a food chain is called a trophic level. Producers are the first level, primary consumers the second, secondary consumers the third, and so on.
Energy enters the chain from the Sun. Producers capture a little of that sunlight and store it as food. When one organism eats another, only about 10% of the energy is passed on — the rest is used up for moving, growing, and staying warm, or is lost as heat. Because so much energy is lost at every step, food chains are usually short (three to five links) and there are always far fewer top predators than producers.
Decomposers are the recyclers. They do not sit at the top of the chain — instead they feed on dead plants and animals at every level and release the nutrients back into the soil, where producers can use them again.
Food chain example: grass to hawk
Here is a classic land food chain. Read it from left to right and follow the arrows — each arrow points from the food to the animal that eats it, showing the direction energy flows.
Food chain vs food web: what is the difference?
In nature, most animals eat more than one kind of food, and most plants and animals are eaten by more than one predator. A single food chain cannot show all of that. A food web joins many overlapping food chains into one diagram, giving a much more realistic picture of an ecosystem.
The key difference: a food chain is a single straight path, while a food web is many chains linked together. The table below compares them.
| Aspect | Food chain | Food web |
|---|---|---|
| Structure | One straight path | Many chains linked together |
| Arrows | A single line of arrows | Many crossing arrows |
| How real | Simplified model | Realistic view of an ecosystem |
| If one species disappears | The whole chain breaks | Other paths can still feed the animals |
Worked examples: building and reading a food chain
Example 1. Build a food chain
Organisms: oak leaves, caterpillar, blue tit (a small bird), sparrowhawk.
Step 1 — Find the producer. The oak leaves make their own food from sunlight, so they come first.
Step 2 — Add the herbivore (primary consumer). The caterpillar eats the leaves.
Step 3 — Add the next consumers in order. The blue tit eats the caterpillar (secondary consumer); the sparrowhawk eats the blue tit (tertiary consumer / top predator).
Step 4 — Draw the arrows from food to feeder:
oak leaves → caterpillar → blue tit → sparrowhawk
Each arrow shows energy moving to the next organism.
Example 2. Read a food chain correctly
Food chain: algae → shrimp → small fish → seal.
- algae — producer (makes food from sunlight in the water);
- shrimp — primary consumer (eats algae);
- small fish — secondary consumer (eats shrimp);
- seal — tertiary consumer / top predator (eats the fish).
The arrows point toward the seal, so energy flows algae → shrimp → small fish → seal. The seal is not the start of the chain — it is the end, where the least energy is left.
Example 3. Turn chains into a food web
In a meadow, a grasshopper is eaten by both a frog and a bird, and the grass is also eaten by a rabbit. That is more than one chain:
- grass → grasshopper → frog
- grass → grasshopper → bird
- grass → rabbit → fox
When you draw all of these together and let the arrows cross, you get a food web. It shows that if the grasshopper disappeared, the frog and bird could still survive by eating other prey — something a single food chain can never show.
Common mistakes with food chains
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Drawing the arrows the wrong way — pointing from the predator to its food (hawk → snake).
Arrows always point from the food to the eater, because they show the direction energy flows. Grass gives energy to the grasshopper, so it is grass → grasshopper, never the other way around.
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Mixing up a food chain and a food web, or thinking they are the same thing.
A food chain is one single path. A food web is many food chains joined together. If your diagram has crossing arrows and animals that eat several kinds of food, it is a web, not a chain.
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Leaving decomposers out, or putting them at the very end after the top predator.
Decomposers such as fungi and bacteria feed on dead matter from every level, not just the last one. They recycle nutrients back to the producers, so they belong to the whole ecosystem rather than sitting at the top.
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Thinking the top predator has the most energy because it is the biggest or strongest.
Only about 10% of the energy passes to each next level, so the top predator actually receives the least energy. Producers hold the most energy, which is why there are always far more plants than top predators.
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Calling every meat-eater a secondary consumer.
The level depends on what the animal eats, not on whether it eats meat. An animal that eats a primary consumer is secondary; one that eats a secondary consumer is tertiary. Trace the chain to find the right level.
Frequently asked questions
What is a food chain in simple words?
A food chain is a diagram that shows how energy passes from one living thing to another as they eat each other. It starts with a producer (a plant), moves through consumers (animals), and the arrows show the direction the energy flows — always from the food to the animal that eats it.
What is the difference between a food chain and a food web?
A food chain shows a single straight path of who eats whom, such as grass → grasshopper → frog. A food web joins many food chains together, so it shows that most animals eat several kinds of food and are eaten by several predators. A food web is a more realistic picture of a whole ecosystem.
What are producers, consumers, and decomposers?
Producers make their own food from sunlight (for example grass and trees). Consumers get energy by eating other living things — primary consumers eat plants, secondary and tertiary consumers eat other animals. Decomposers, such as fungi and bacteria, break down dead plants and animals and return the nutrients to the soil.
Which way do the arrows point in a food chain?
Arrows always point from the food to the organism that eats it, because that is the direction energy travels. For example, grass → rabbit means the rabbit eats the grass and gains its energy. Drawing the arrow the other way is one of the most common mistakes.
Can you give a simple food chain example?
A classic land food chain is grass → grasshopper → frog → snake → hawk. Grass is the producer, the grasshopper is a primary consumer, the frog is a secondary consumer, the snake is a tertiary consumer, and the hawk is the top predator. An ocean example is algae → shrimp → small fish → seal.
Why are food chains usually short?
Only about 10% of the energy is passed on at each step — the rest is used for moving, growing, and keeping warm, or lost as heat. After four or five links there is not enough energy left to support another level, so food chains are usually only three to five organisms long.
