1. Physical Processes P

2. Earth has been changing for million of years.
Most of the changes are slow, but some happen quickly. The changes, whether they are fast or slow, affect all living things on Earth

3. Life in an Ecosystem
Plants and animals and the environment in which they live make up an ecosystem
The members of an ecosystem affect one another in many ways.

4. Life in an Ecosystem
In a forest, for example, the trees provide shelter and food to birds, insects and other animals.
They also provide shade for other plants.
The birds and animals help spread the trees’ seeds, and the insects help break down fallen logs.
The environment provides the soil and the weather the trees need to grow.

5. Life in an Ecosystem
If a forest is cut down, the environment changes. Without the trees, plants that need shade die.
Birds and animals must move on to find new homes. With no roots to hold the soil in place, it washes and blows away.
When one part of an ecosystem disappears, all the other parts are affected

7. What can happen to an ecosystem when a forest is cut down?

8. What can happen to an ecosystem when a forest is cut down?
The environment changes, and birds and animals must find new homes

9. Slow Changes to the Earth
Some physical processes that affect Earth are slow and take millions of years to change things.
For example, scientists know that at one time there was just one huge continent.
Over time it broke into several smaller ones, which are still slowly drifting apart.
Humans living on the continents today are hardly aware that this movement is happening

10. Slow Changes to the Earth
Another very slow physical process is erosion.
Erosion is the wearing away of Earth’s surface.

11. What are two natural processes that are slowly changing Earth?

12. What are two natural processes that are slowly changing Earth?
The moving of continents
Erosion

13. https://www.youtube.com/watch?v=G5Rp 9MJJGCU
Erosion video

14. Sudden Changes to the Earth
Some physical processes that affect Earth happen very quickly.
Activity taking place beneath Earth’s surface can cause earthquakes and the eruption of volcanoes.
Floods, powerful storms, forest fires, and other disasters can change an area in a matter of days.
A disaster is an event that causes great harm or damage.

16. Sudden Changes to the Earth
Natural disasters can cause great harm to plants and animals.
When they happen where people live, they destroy property and make life difficult.
People need to learn how to prepare for natural disasters