Aims of this Episode

  • Define producer, primary and secondary consumer, predator and prey;
  • Describe the cause and effect of bio-accumulation,
  • Describe the structure of a food chain or food web,
  • Explain to role of different animals in a food chain or food web.

Food chains and food webs are simply ways of seeing what animals eat and how energy is transferred from the sun to the very top predator. The producers are often the plants at the very bottom and predators are the animals towards the top. Click here for a great video explaining food chains and food webs.

Key definitions

Producer the organism at the very bottom of the food chain. On land they are usually plants, whilst in the sea they are plankton. Either way, they get their energy from the sun and store it in a chemical form.

Consumer – these are animals that eat plants or other animals (basically anything that’s not a producer). You can find primary consumers that eat the producers and secondary consumers that eat plants and/or other animals (also known as Carnivores and Omnivores).

Predator – animals that eat other animals; these can also be classed as secondary consumers.

Prey – animals that get eaten by other animals. Most of the time predators are also prey to another animal. Both primary and secondary consumers can be prey.

If an animal is not prey to anything else then it is called an Apex Predator.


When toxins are released into the environment they might be spread out, so animals aren’t initially harmed by them. Producers will absorb some of the toxins and when they are eaten by primary consumers they pass the toxins on. Since the primary consumers eat many producers they will have a lot more of the toxin in their body than the producers did. As predators eat these primary consumers the concentration of the toxin will increase. Eventually, usually near the top of the food chain, the toxin levels are so high that it can kill the predators or seriously harm their babies. This effect is call bio-accumulation because the toxin is accumulating as it goes up the food chain.

Click here for a video helping to explain it.

Finally, here’s the pictures of the Baboons on the front of the car…

S@S 024: Food Chains and Habitats (GCSE Biology)
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