Page 39 - Science Coursebook

2.8 Habitat destruction

This palm oil plantation is
growing where there was
once tropical rainforest.
Coral reefs

Coral reefs are sometimes called ‘the rainforests of the
sea’. This is because they have a very high biodiversity.

Coral reefs are built by tiny animals similar to sea
anemones. They live together in big colonies, and make
hard coverings around themselves. These coverings are
made from calcium carbonate.
The coral animals have tiny algae growing inside them.
The algae make carbohydrates by photosynthesis. The
coral animals use the carbohydrates for food.

Many different species of invertebrate animals and fish

live their whole lives in coral reefs. Other animals, such
as turtles and sharks, visit coral reefs to feed.
One of the biggest threats to coral reefs is acidification of

sea water. Carbon dioxide in the air dissolves in sea water
to produce a weak acid. The acidic sea water makes it

difficult for the coral animals to build their skeletons. Coral reefs have a huge biodiversity.

Questions
1 Explain each of these statements:
a The growing human population on Earth is causing habitat destruction.
b Habitat destruction can cause species to become extinct.
A+I 2 What are the producers in a coral reef?
3 Think about what you learnt about air pollution in Stage 7. Explain what is
happening to the amount of carbon dioxide in the air.

A+I 4 Think about what you learnt about the reactions between carbonates and
acids in Stage 8. Explain what might happen to the calcium carbonate in
coral reefs, if the sea water becomes more acidic.

Summary
• Humans destroy the habitats of animals and plants.
• Each species is adapted to live in a particular habitat. If that habitat is
destroyed, the species may become extinct.

2 Living things in their environment 37