1. Earth’s History Section 4.1

2. Observe Look at the Picture on page 74:
What does this photograph show?
What features make you think it is a bird?
How do you know it’s a fossil?
How do you think this fossil was formed?
What does the picture have to do with the subject of this chapter? (Earth’s History)

3. Time to change Look around your classroom and look outside.
Make a list of ten objects or conditions inside and outside your classroom that don’t seem to change from day to day.
Write down one way that each item could change and how long it would take.

4. change What do you think of when you hear the word change?
How will you change in the next 10 years?
How will the Earth change in the next 10 years?
Does the way you change differ from the way the Earth changes? How?

5. Age of the earth The Earth is 4,600,000,000 years old.
Earth’s history is very long
It’s longer than human experience.
Geologic Time- special name for the time scale of the history of the earth and its life.

6. Origin of the Earth
5,000 million years ago there was a cloud of matter spinning in space.
It began to collapse and drew in matter from the surrounding area to the center from a gravitational pull.
As this happened the center became hot and dense and through the process light and heat were released creating our sun.
Surrounding matter began to clump and then planets and eventually Earth was born.

7. Earth’s Early History During the first billion years
No oceans
No continents
No atmosphere
Only volcanoes constantly erupting and spewing gases
Then an atmosphere started to form and some gases condensed creating water.
~3,800 million years ago:
First land masses had formed from volcanic eruptions.
First living things came into being in oceans
Some producing Oxygen

8. Earth’s Early History ~ 2,000 million years ago:
Earth similar to today
No organisms on land yet
Mountains and Rivers existed
Atmosphere contained Oxygen
Energy from the sun created weather patterns.

9. Changes on the surface Over the last 2,000 million years:
Change has continued but changes have followed regular patterns.
4 types of surface changes:
Weather and Erosion
Deposition
Formation of Sedimentary Rock
Uplift

10. Weather and erosion
Weathering- rocks are broken up into smaller particles by the action of water, atmosphere, and organisms.
Earth’s surface can be shaped by weathering and erosion, where weathering happens first, then erosion happens second.
Erosion- smaller particles of rock are displaced by moving water, wind, or ice.
Sediment- particles carried away by erosion.
Weathering and erosion work slowly, but over time can cause major changes.

11. deposition
Particles of erosion travel to low places because of gravity.
Deposition- buildup of eroded particles or sediment.
Deposition is a building-up process.
Slow process that is happening all of the time.

12. Formation of Sedimentary Rock
Sediment builds up over long periods of time and it causes horizontal layers on the earth.
With newer layers on top of older ones.
With more layers on top pressure
is put on the lower layers
Pressure causes sediments to compact
together and become rock.
Sedimentary Rock- rock that forms from sediment.
The deeper the layer of sedimentary rock, the older it is.

13. Uplift Why do we have mountains and high places?
Why isn’t the world flat?
Uplift- process where parts of the crust are raised above others.

14. Questions What are the four ways that cause Earth’s surface to change?
Which comes first, weathering or erosion?
How are weathering and erosion different from deposition?
What would the world look like without uplift?
Where can we see examples of sedimentary rock?

15. Changes in Life Organisms have lived on Earth for millions of years.
We can see evidence of life through fossils.
Fossil- remains or traces of an organism, found in rocks of the crust, that lived in the past.
Most are formed when organisms were buried in the sediment.
A fossil is as old as the rock it’s found in.
Studying of fossils shows change in organisms over time.
Many no longer exist (extinct).

16. Change in climate
Climate has varied a lot throughout the history of the Earth
It was both dry and cold and wet and warm.
When dry and cold:
Polar ice caps increased in size
Ice sheets spread to middle latitudes
Ice Age- periods where ice caps and ice sheet increase.
Most changes in climate are slow
Humans and technology have changed climate on a local and global scale in a faster process.

17. On ice
When sheets of ice expand and advance from the poles, much of Earth’s water is frozen in ice.
What do you think might happen to the ocean levels?
How might this affect shoreline erosion?
State a hypothesis to explain your reasoning.

18. What have we learned? From what did the earth form?
What does erosion do to the earth’s surface?
How would a layer of sedimentary rock formed from mud be different from one formed from sand?
Using words and arrows, draw a diagram to show how weathering, erosion, deposition, sedimentary rock formation, and uplift are related?