Page 38 - Science Coursebook

2.8 Habitat destruction

All living organisms have adaptations that help them to live in their habitat. If
humans destroy their habitat, then they may not be able to survive. Some species
may become extinct. This means that all the members of that species will be dead.
Once a species is extinct, it cannot ever exist again.
As the human population increases, we are destroying more and more habitats.
The main reasons for this are:
• using more land to grow crops and farm animals, to provide food for more people
• building more homes and roads

• cutting down forests to provide firewood and timber for building
• mining, to obtain more minerals from the ground.

Many different kinds of habitats are being destroyed. The ones that contain the
most species are wetlands, rainforests and coral reefs.

Wetlands
A wetland is a place such as a swamp,
marsh or bog. Some wetlands are
inland, and some are next to the sea.
Some wetlands stay wet all year round,
while others dry out at some times of
the year. Many plants and animals are
adapted to live in wetlands.

The most important threat to wetlands
is that people drain the land. They do These wetlands are in Sri This used to be a wetland.
Water has been taken away
Lanka. What can you see in the
this so that they can use it to grow crops, photograph that suggests that from it to use to irrigate
or to build on. Sometimes, wetlands they are not wet all the agricultural land. The plants
near the sea are dug away to make deep year round? are dying, because they
water harbours. This has happened to are adapted to live in wet
huge areas of wetlands all over places, not dry ones.
the world.

Rainforests
Rainforests grow in the tropics, and also
in cooler, temperate regions. They are

the habitats for many different species
of plants and animals. We say that they
have a very high biodiversity.
Humans have cut down vast areas of
rainforest. Many species of plants and
animals that are adapted to live in This rainforest in the Amazon Orangutans need large areas
rainforest habitats have already become in Peru may look undamaged of rainforest to live and breed.
extinct. Many others are endangered. but it has no large trees Deforestation in Borneo
This means that there are so few left because they have been threatens them with extinction.
that they may soon become extinct. logged (cut down).

36 2 Living things in their environment