Coral. What is coral (a family of living creatures - anthozoa - related to the sea anemone)? Where are they found (live in colonies in shallow, warm seas)? What is a coral reef (some corals - madreporaria - secrete a hard calcium carbonate - lime - external skeleton; the accumulated skeletons of dead coral build up beautiful, delicate, stone-like tentacle formations)? If there are large reefs, why are they endangered (recently starfish have destroyed 30 per cent of the 15,000-year-old Great Barrier Reef off north-east Queensland, Australia - find it on a map - which is about 1,000 miles long, though many are smaller; pollution, such as oil spills, dumping of waste, and soil erosion, can wear away or kill the coral)?

Jewellery. Why do people wear jewellery (to adorn themselves, show allegiance, for example, wedding or engagement ring, draw attention to or cover up certain features)? What materials are used (metals such as silver and gold; precious and semi-precious stones such as diamonds, rubies, garnets; naturally occurring substances such as amber, coral, ivory)? Do you or your friends and family wear jewellery; if so, what, and who bought it? Is it symbolic (marking an event, a special gift)? Should jewellery be worn only by women, or is it suitable for men? Should people pierce their bodies (earrings) or is this unnatural? Why are certain adornments seen as anti-authority?

Symbiosis. What is a symbiotic relationship (two species living in harmony, each benefiting from the other, unlike a parasitic relationship, where one feeds off the other)? Can you think of examples (symbiotic - insects and plants in pollination; parasitic - mistletoe, fleas)? How do corals live in symbiosis (with algae, which offer nutrition in exchange for carbon dioxide; with fish, gaining nutrients from excretions in exchange for protection from predators)? Are relationships between children and parents symbiotic or parasitic?

Writing. Imagine that you have the ability to swim underwater and inspect the reef in the picture. Describe, as vividly as you can, your experiences.

Ted Wragg is professor of education at Exeter University

TALKING POINTS

SHOULD THE SALE OF JEWELLERY MADE OF CORAL BE BANNED?

For The high price of coral jewellery offers an incentive to destroy delicate reefs that have taken years to form. There are plenty of other suitable materials, including man-made materials that look like coral. Many people do not realise the threat to coral, and a ban would bring home the dangers.

Against The coral reefs are vast and many remain undetected. In some poor countries it is an important source of income. Plastic jewellery looks cheap compared with real coral, which is beautiful and natural. Unscrupulous dealers will ignore a ban, which would simply push up prices and lead to an uncontrolled black market.