1. Arrival: What did baby Earth look like?

2. History of the Earth
The Earth has existed for 4.6 billion years. The geologic time scale divides all those years into sections. The history of the Earth can be broken down into 4 time periods: Precambrian Era, Paleozoic Era, Mesozoic Era & Cenozoic Era

3. How is time divided?
Major changes in Earth’s history mark the boundaries between the sections.
Most sections have been divided because a major organism developed or went extinct.

4. Extinction Extinction = the death of every member of a species
It can happen because of competition between the species, so some organisms ran out of food or space
It can happen because the environment changed, and some organisms could not survive in the new environment.

5. Mass Extinction
Mass extinction = the extinction of many species at the same time
Can you think of an example of a mass extinction?
It can be caused by gradual changes in climate or ocean currents (Uniformitarianism)
Or by catastrophic events, like an asteroid hitting the earth and blocking out the sun (Catastrophism)

7. Precambrian Era Put these statements in order in your notes.
The creation of the oceans
The creation of life
The creation of the earth
The creation of the atmosphere through volcanic outgassing
The formation of the Sun and light
- video on precambrian era (4mins)

8. Precambrian Time
Time from the formation of the Earth (4.6 billion years ago) to 542 million years ago
The Earth was very different then
At first, there was no oxygen or living things
Then the first organisms appeared in the oceans billion years ago
They were called Prokaryotes

9. Paleozoic Era
Began 542 million years ago and ended 251 million years ago
Divided into 6 periods
Many new life forms appeared during the 1st period, the Cambrian Period = “Cambrian Explosion”
For the first time on Earth, organisms had hard parts (shells, exoskeletons)
Some organisms that were alive during this period still exist today

10. Fill in the following table in your notes for both the Precambrian & Paleozoic Era
Life Forms Present at Start
Life Forms Present at End
Any extinctions?
Any opportunities for Fossils?

11. Assignment Comic Strip
Produce a comic strip that shows the timeline of the Precambrian Era. Use the criteria on the back of your template as a guide.

12. Plenary Quiz