1
How people change habitats
Discover P2 Term 1: Axis 2, Chapter 2
GoalExplain how people change habitats, using the Aswan High Dam as an example, and tell helpful changes from harmful ones.
New words
dam · a strong wall across a river that holds water backchange · making something differentharm · to hurt or damage something
Explanation
People change habitats when they build houses, make farms or cut down trees. A dam is a strong wall across a river that holds water back. The Aswan High Dam is built across the Nile. It keeps water in a big lake, and it helps make electricity. Before the dam, the Nile flooded every year. Now the water is kept for the dry months. The change helps people, but it also changes the river habitat for plants and animals. Some changes help. Some can harm. A good thinker looks at both.
| What the dam does | How it helps people | What changes for nature |
|---|---|---|
| keeps water in a lake | water for farms in dry months | the river habitat changes |
| the yearly flood stops | fields and homes are safer from floods | the flood no longer covers the land |
| makes electricity | light for homes | — |
Worked examples
People build houses on land that was a field. People get homes, but the plants and birds of the field lose their place.
A class plants a tree in the schoolyard. A tree gives shade and a home for birds. This is a helpful change.
A plastic bag left on the beach can harm a sea turtle. This is a harmful change, and we can stop it.
Class activity
Change walk with a grown-up. Walk around your street or park and look for a change that people made: a new building, a road, a planted tree. Draw it. Say who it helps. Then say if any plants or animals might lose something.
Practice
1
What is a dam?
A strong wall across a river that holds water back.
2
Name one thing that the Aswan High Dam does.
Any one of: it keeps water in a lake; it keeps water for the dry months; it helps make electricity.
3
Which of these can harm sea animals if it is left on the beach? Say the letter.
B, the plastic bag.
4
Why should we think about plants and animals before we change a place?
They live there and they need it as their home.