REPRODUCTION

Egg Adaptation

You will need a raw egg and a sink.

Take an ordinary raw egg and try to break it by gently squeezing across its middle and along its length. Try other ways of breaking by using just your hands.

Eggs are very difficult to break by squeezing. They are a marvellous adaptation for survival.

Seed Germination

Safety rules:

Parent supervision

Take care with glass

Materials you need are:

some seeds (e.g. alfalfa seeds from the health food shop)

2 sheets of glass

paper towel

rubber bands or sticky tape

some water

supports

Place some seeds on moist paper towel between two sheets of glass secured with rubber bands or sticky tape. Stand this upright in a place that cannot be disturbed. As soon as they germinate, turn the whole apparatus vertically through 90 degrees and allow it to remain undisturbed for a two days. Repeat the procedure by turning the whole apparatus another 90 degrees vertically and again allow it to remain undisturbed for two days. At the end of this time, carefully pull the apparaus apart and observe which way the roots and shoots grew. Do all the shoots grow upwards and all the roots grow downwards?

Gravity affects the germination of seeds. Roots show a positive response to gravity (positive geotropism) and grow downwards towards the centre of the earth. Shoots show a negative response to gravity (negative geotropism) and grow away from gravity.