All food chains begin with energy from the Sun. Plants capture this energy through photosynthesis and store it in their leaves, stems, and roots. This makes plants the start of almost every food chain.
Check: Why are plants called producers?
Flowchart
Use the pathway to build a clear mental model. Open each node and answer the check question.
1) Energy starts with the Sun
2) Energy flows through consumers
Animals that eat plants are primary consumers (herbivores). Animals that eat other animals are secondary consumers (carnivores). The arrows in a food chain show the direction energy flows: from eaten → to eater.
Check: Which way does the arrow point - towards the food or towards the eater?
3) Food webs show connected food chains
Most organisms eat more than one type of food and are eaten by more than one predator. A food web shows all the connected food chains in an ecosystem - it's more realistic than a single chain.
Check: Why is a food web more realistic than a single food chain?
4) Changes affect the whole web
If one organism in a food web increases or decreases, it affects all the others connected to it. If rabbits decrease, foxes might go hungry; if foxes decrease, rabbit numbers might explode.
Check: What might happen if a disease killed all the grass in an ecosystem?
Explanation
What is a food chain?
A food chain shows how energy passes from one organism to another through feeding. Each step is called a trophic level:
- Producer (plants) - makes food using sunlight
- Primary consumer (herbivore) - eats plants
- Secondary consumer (carnivore) - eats herbivores
- Tertiary consumer (top predator) - eats other carnivores
Reading Food Chain Arrows
The arrow means "is eaten by" or "energy flows to". It points FROM the food TO the eater:
Grass → Rabbit → Fox
This reads: "Grass is eaten by rabbit, rabbit is eaten by fox" OR "Energy flows from grass to rabbit to fox".
What is a food web?
A food web is many food chains connected together. It shows that:
- Most animals eat more than one type of food
- Most organisms are eaten by more than one predator
- Energy flows through multiple pathways
Key Vocabulary
- Producer: an organism that makes its own food (plants).
- Consumer: an organism that eats other organisms.
- Herbivore: an animal that only eats plants.
- Carnivore: an animal that eats other animals.
- Predator: an animal that hunts and eats other animals.
- Prey: an animal that is hunted and eaten.
Examples
Example 1: A British woodland food chain
Oak tree → Caterpillar → Blue tit → Sparrowhawk. The oak produces leaves, caterpillars eat the leaves, blue tits eat caterpillars, and sparrowhawks eat blue tits. Energy flows through each level.
Example 2: A pond food chain
Algae → Water flea → Stickleback → Heron. Tiny algae are eaten by water fleas, which are eaten by small fish (sticklebacks), which are eaten by herons. The heron is the top predator.
Example 3: A garden food web
Lettuce is eaten by slugs AND caterpillars. Slugs are eaten by hedgehogs AND thrushes. Caterpillars are eaten by thrushes AND blue tits. All these chains connect to form a food web showing multiple pathways for energy flow.
Example 4: What happens when a link breaks
In the 1950s, myxomatosis killed most British rabbits. Foxes had to find other food. Grass grew taller without rabbits eating it. Rabbit burrows disappeared, so fewer ground-nesting birds could nest. One change affected the whole ecosystem.
Practice
Answer all questions, then check your answers. Your quiz result is saved on this device.
Common Mistakes
Mistake 1: Drawing arrows the wrong way
Wrong: Fox → Rabbit (this says "fox is eaten by rabbit"). Correct: Rabbit → Fox (rabbit is eaten by fox). Remember: arrows show where energy GOES, from food to eater.
Mistake 2: Starting a food chain with an animal
Wrong: Rabbit → Fox → Wolf. Correct: Grass → Rabbit → Fox. Food chains (almost) always start with a plant/producer because that's where energy first enters the ecosystem from the Sun.
Mistake 3: Thinking animals only eat one thing
Wrong thinking: "A fox only eats rabbits." Correct: Foxes eat rabbits, voles, birds, berries, and even worms. That's why food webs are more realistic than food chains - they show multiple food sources.
Mistake 4: Forgetting decomposers
Wrong thinking: "Energy just disappears when organisms die." Correct: Decomposers (bacteria, fungi) break down dead organisms and return nutrients to the soil, where plants use them. The cycle continues!
Summary
- Food chains show how energy flows from producers through consumers.
- Arrows point from the food to the eater (showing energy flow direction).
- Food chains start with producers (plants) that capture energy from the Sun.
- Food webs show connected food chains - more realistic because most organisms have multiple food sources.
- Changes to one part of a food web affect all connected organisms.
Skills Checklist
- I can construct a food chain with arrows pointing the correct way.
- I can identify producers, consumers, herbivores, and carnivores.
- I can explain why food webs are more realistic than food chains.
- I can predict what might happen if one organism in a web changes.