1. Monday, January 4th, 2016
Materials:
Pencil
Notebook
Computer
Agenda:
Pre- Cambrian Era Notes
DO: Today we will Learn about Earth history starting with the pre-Cambrian era.
DQ: What do you think Earth was like during the Pre-Cambrian Era? How long ago do you think this was?

2. Earth History Review Pangea – Connecting time eras in Earth’s history.

3. Go to X Students7th Grade  7C- Merritt Class period Earth History
COPY the “Earth History Notes” document to your H drive.
Open & Start Editing
** You will be typing notes with this document for the next two weeks!

5. Precambrian Age 4.6bya-500mya
Eon: a unit of time equal to a billion years.
Subdivided into eras
Era: a long and distinct period of history with a particular feature or characteristic. Subdivided into periods.
Period: Identified by distinct features/characteristics. May also be subdivided into epochs and ages.
The Hadean Eon billion years ago (bya)
The Archean Eon bya
The Proterozoic Eon 2.5 bya-542 mya

6. (Hadean)Formation of the Earth
Planets form
Gaseous Jupiter forms first
Collisions form inner metallic planets
Icy asteroids deliver water

7. The Hadean Eon Solar System forms
Solar nebula collapses due to gravity
Proto-sun forms from hydrogen gas and begins hydrogen fusion
Dust particles condense, and clump

8. Formation of Earth’s Crust
The Moon was formed between Earth and a smaller planet occupying the same orbit
Dense iron magma sinks to core
Lighter silica magma rises to
form magma ocean
Magma cools and forms
crust
Oldest surviving continental crust
3.8 bya Acasta Gneiss, Canada

9. Late Heavy Bombardment from Space
Asteroid belt is disrupted by migration of the outer icy planets
Zircon grains found that are 4.3bya in metamorphic and sedimentary rock, confirming a modern rock cycle was in operation
Formation of oceans and atmosphere
Video – Formation of Pre-Cambrian Era

11. The Archaen Eon Crust cools & Plate tectonics is established
Atmosphere composed of nitrogen, hydrogen, carbon, but very little oxygen
The first life appears and forming the earliest fossils
Complex chemical reactions change carbon molecules into earliest life forms
First photosynthetic organisms produce oxygen

12. Proterozoic Eon Protero= first Zoon= life in Greek
First multicellular animals by end of interval
Larger land masses form from the accretion of smaller ones
4 major mountain-building episodes Continents begin to erode into oceans creating marine environments where life could diversify
Increasing oxygen in the atmosphere caused some life forms to go extinct, while allowing others to flourish
Oldest known glaciers