2. Earth Systems and Resources (10%–15%)
Soil & Geology
Earth Systems and Resources (10%–15%)
Earth Science Concepts (Geologic time scale; plate tectonics, earthquakes, volcanism; seasons; solar intensity and latitude)
Soil and Soil Dynamics (Rock cycle; formation; composition; physical and chemical properties; main soil types; erosion and other soil problems; soil conservation)

3. Identify Each

4. Tells us the order of events, not how long ago they happened.
Relative Dating
Tells us the order of events, not how long ago they happened.
Natural processes that take place today also took place the same way in the Earth’s past.

5. Law of Superposition
- oldest layers are at the bottom and the younger layers on top

6. Principal of Cross Cutting Relationships
- Layers that cut across other layers of sedimentary
rocks are younger than the layers they cut across

7. A
Glacial Lake B C
Fault
Igneous Dike D E

8. Fossils are the preserved remains or traces of prehistoric life.
Normally bones, teeth and other hard parts of organisms
Fossils can also include indirect evidence of organisms: Preserved footprints Preserved burrows Gastroliths *

9. Principle of Fossil Succession
- Fossils succeed one another in a specific order. Any time period can be identified by the fossils found in the rocks.
Ex. We know that dinosaur
bones are found before
mammoth bones.
These are called Index Fossils. *

10. Absolute dating provides very accurate ages of rocks by measuring the breakdown of radioactive atoms.
Each type of radioactive atom breaks down at known rates called a half-life.
The half-life of an atom is the amount of time it takes for half of the material to break down. *

11. 1/2
1/4
1/8
1/16
Kilogramsof Material *

12. Uranium 235 ------------------> Lead 207
Example:
Uranium > Lead 207
The half life for U-235 is about 700 Million years
If we start with 100g how much will be left after 3 half lives have passed?
We have 25g and started with 400g. How old is this sample?
Practice Handout: Homework! *

13. From Largest to Smallest…
Geologic Time Scale
- Earth’s History is broken up into parts based on changes in geology and the life of the planet.
From Largest to Smallest…
Eon > Era > Period > Epoch *

14. The Five Mass Extinctions
- Five times in Earth’s history there has been periods where a large percentage of species on the earth went extinct.
It is widely agreed that humans are currently causing the sixth mass extinction event in Earth’s History *

15. Video Notes: Causes of 5 mass extinctions
Name
Suggested Causes
Who died?