Darwin’s idea to explain evolution was natural selection. That: living things produce offspring which vary — they are not all the same, there is a shortage of resources (food, light, places to live, animals to mate with etc.), individuals that do best in this ‘competition for survival’ will tend to leave more offspring, passing on their successful features to the next generation. This is adaptation. Remember him? Charles Darwin.

The practical investigation we are going to carry out provides a simulation of natural selection, using birds to help in the process: it’s bird-powered evolution!

Aim: To investigate how the colour of worms evolved over time. Put two different-coloured spaghetti ‘worms’ on the bird table for birds to feed on. Each day the ‘worms’ that have not been eaten will be allowed to ‘breed’. Over time, the numbers of the two different types of ‘worms’ will change and this will show natural selection.

1) Put two different-coloured spaghetti ‘worms’ on the bird table for birds to feed on. 2) Take a photograph of the area to record the positions and numbers of the ‘worms’. 3) The next day Collect the ‘worms’ of each of the two types, putting them into separate containers. 4. Count how many of each sort of ‘worm’ is present, then calculate the number of ‘worms’ that must have been eaten by the birds. 5) Calculate how many new ‘worms’ now need to be placed on the feeding area. Method

Safety Birds carry parasites and bacteria such as Salmonella. Therefore it is important that you wear disposable plastic gloves when handling food that birds and other animals might have been in contact with and that you wash your hands after doing so.

Fair Test What will you change (Independent variable)? What factors will you keep the same (Controlled variables)?

Girl: I think the reds will have disappeared the most because I think that’s the most natural colour to a worm, rather than the vibrant green. Boy: I think the greens might have disappeared the most because birds are used to hunting worms in grass, which is the same colour as green, so I think a load of greens are going to have gone. Prediction What do you think will happen and why?