IGCSE Geography – Coral Reefs Quiz (Year 11)

Coral reefs are made mainly from?

• Sand and shells

• Volcanic rock

• Calcium carbonate from coral skeletons

• Dead seaweed

Coral polyps live in a symbiotic relationship with?

• Plankton

• Zooxanthellae (algae)

• Crustaceans

• Sea urchins

Why do coral reefs only grow in shallow water?

• Less wave energy

• More nutrients

• Sunlight is available for photosynthesis

• Less competition

Which temperature range is best for coral growth?

• 10–15°C

• 15–20°C

• 23–29°C

• Above 35°C

Which reef type forms directly along the coastline?

• Atoll

• Barrier reef

• Fringing reef

• Patch reef

Coral bleaching happens when?

• Coral dies completely

• Coral loses its zooxanthellae

• Coral is covered by sediment

• Coral is eaten by fish

Which statements correctly describe the symbiotic relationship between coral polyps and zooxanthellae?

• Polyps provide shelter and waste products (nutrients)

• Zooxanthellae photosynthesise

• Zooxanthellae provide food/energy to coral

• Neither organism benefits

• Zooxanthellae remove coral skeletons

Which conditions are needed for coral reef growth?

• Warm water (about 23–29°C)

• Deep water

• Clear water

• Low sediment levels

• Low nutrients

Which reasons explain why coral reefs are described as ‘highly biodiverse’?

• Many different species

• Few habitats/niches

• Supports fish, invertebrates, algae, predators

• Low species variability

Match each reef type to its description.

• Ring-shaped reef around a lagoon, formed from submerged volcano

• Atoll

• Offshore, lagoon between reef and land

• Fringing reef

• Close to coast, shallow, no lagoon

• Barrier reef