Science Checkpoint Revision: Ecosystem

In a food chain a producer is ​ (a)  

• an organism that makes its own food, like plants.
• where people make something.
• an organism that eats other animals.

'Toxic' means ​ (a)  

• an animal.
• edible.
• poisonous.

This food chain is incorrect. State what is wrong with it and then write the correct food chain.

In a food chain, a consumer is ​​ (a)  

• someone who buys things to eat.
• an organism that does not make its own food.
• a tree.

Reorder the following to explain how a toxic substance like mercury is passed along the food chain.

• Those fish are eaten by humans, people could be poisoned.

• Then, small organisms are eaten by small insects in the water.

• Mercury in the water is taken in by small organisms.

• Then, insects are eaten by bigger fish.

1. Why are top predators most at risk from pollutants in an ecosystem?

2. The top predators are most at risk because, to stay alive, they ​ (a)   which might have ​ (b)   . The small animals have ​ (c)   in them but because top predators eat ​ (d)   , they ​ (e)   from all the fish they eat in their bodies.

• must eat a lot of other animals
• poison in them
• a little poison
• so many of them
• accumulate the poison