Lesson 6 of 6
Toxins in food chains
Goal: Explain how toxic materials build up along a food chain.
Some toxic materials build up inside living things. This is bioaccumulation. The amount gets bigger at each step of a food chain.
- Some toxins stay in the body. Certain pesticides, and metals such as mercury, are taken in faster than the body can break them down or pass them out.
- Each animal eats many of the living things below it in the chain, and takes in the toxin from every one of them.
- The top predator ends up with the highest level, so it is the most likely to be harmed. In the 1950s and 1960s a pesticide called DDT built up in birds of prey. Their eggshells became thin and broke, and their numbers fell.
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Key words in this lesson
Food chain Shows what eats what, in one line that starts with a producer
Predator An animal that hunts and eats other animals
Prey An animal that is hunted and eaten
Bioaccumulation The build-up of a toxin inside living things