1. Starter; Write down as many food chains as you can from this food web.
sparrowhawk
owl
robin
stoat
earthworm
mouse
rabbit
leaves and berries
dandelion

2. Starter; Write down as many food chains as you can from this food web.
sparrowhawk
owl
robin
stoat
earthworm
mouse
rabbit
leaves and berries
dandelion
(How many carnivores are in the food web? How many herbivores? Name them.)

3. Starter; Write down as many food chains as you can from this food web.
sparrowhawk
owl
robin
stoat
earthworm
mouse
rabbit
leaves and berries
dandelion

4. Starter; Write down as many food chains as you can from this food web.
sparrowhawk
robin
earthworm
leaves and berries

5. Today’s learning objectives!
Name a pesticide which will not break down in the environment.
Describe how pesticides can kill other organisms.
Explain advantages of using biological control over pesticides.

6. Toxic food chains What are pesticides used for?
DDT, a useful pesticide, was found to have lots of toxic effects on the environment, especially birds.
DDT is not easily broken down by the environment.

8. Bioaccumulation Each leaf receives one “dose” of DDT when sprayed.
Each worm eats 3 leaves, and receives 3 doses of DDT.
Each robin eats 2 worms.
Each sparrowhawk eats 2 robins.
How many doses of DDT does the sparrowhawk eat?
If they eat enough DDT, birds lay eggs with very thin shells, which break before they are ready to hatch. How might this effect the sparrowhawk population, and the other members of the food chain?

10. Today’s learning objectives!
Name a pesticide which will not break down in the environment.
Describe how pesticides can kill other organisms.
Explain advantages of using biological control over pesticides.

14. Today’s learning objectives!
Name a pesticide which will not break down in the environment.
Describe how pesticides can kill other organisms.
Explain advantages of using biological control over pesticides.

15. What do you think these people are doing?
Why?

16. Let’s play ...
true or false

17. Pesticides reduce crop yield.
False

18. Bioaccumulation is where the first organism to swallow pesticide is the most damaged.
False 18

19. Biological control agents are organisms released into a food web to control the amount of another species.
True 19

20. Aphids are an example of a biological control agent.
False 20

21. Poisons can be passed through food chains and get more concentrated at each step.
True 21

22. Are green plants important?
True 22

23. Do all living things die?
True 23