During this activity, you will use some common food items to make a model of a coral polyp.

Activity Steps

1. Pick up the section of banana or marshmallow. This is your coral polyp.
2. Use the toothpick to make a hole in the top of the banana or marshmallow to represent the polyp’s mouth.
3. Make six smaller holes around the outside of the banana or marshmallow. This is where the tentacles will go.
4. Cut the gummy straws into six equal sections and stick them in the holes you have just made.
5. Add the sugar sprinkles to the surface of the polyp to represent the algae (zooxanthellae).
6. Place your polyp on the cracker or biscuit, using the jam as ‘glue’. This represents the polyp sticking to the seafloor.
7. Stick pieces of the cracker or biscuit to the outside of banana or marshmallow with jam, to represent the corallite.
8. You can make a coral colony by building several polyps and putting them together on the same plate.
9. Once you have made your single polyp or colony, you can learn about parrotfish feeding habits, so that you can copy them.
10. Parrotfish have no hands and so as a true coral predator, you will now have to try to eat the coral polyp without using your hands! This is much easier than copying another coral predator, the crown-of-thorns starfish, which ejects its guts over the surface of the coral to dissolve the polyps and coral structure, and then absorbs this gloop.

More ideas

Try this with a group of friends and see how many incredible edible polyps you can make to create a coral colony or reef. What else could you add to your incredible edible polyp to make it more realistic?

• Scissors
• Toothpick
• Section of banana (approx. 3cm thick) or large marshmallow
• Gummy straws / Twizzlers (approx. 30cm in total)
• 2 round hard biscuits or crackers (approx. 4cm – 5cm across)
• Sugar sprinkles (preferably green)
• Jam (or jelly)

Coral polyp anatomy

Compare your incredible edible polyp with some of the anatomical information below.

1. Polyp – the coral polyp is the animal that builds the coral reef. It is related to jellyfish and sea anemones.
2. Mouth – the polyp has a mouth in the center of its body.
3. Zooxanthellae – coral polyps receive 70 to 90 per cent of its energy from tiny algae, zooxanthellae, that live inside their tissue.
4. Tentacle – the polyp uses its tentacles to catch prey such as copepods, a small shrimp-like animal. Hard coral polyps have multiples of six tentacles.
5. Nematocyst – the stinging cells inside the tentacles used to catch prey.
6. Corallite – the calcium carbonate ‘cup’ and part of the coral structure that makes up the coral reef. The corallite helps to protect the polyp from predators.