Peter Douglas - The History of the Earth

Question 1

What is Uniformitarianism?

Answer 1

The same natural laws and processes that operate on the Earth now have always operated on the Earth. –“The present is the key to the past”

Question 2

What is Catastrophism?

Answer 2

The Earth has in the past been affected by sudden events with a world-wide impact

Question 3

What is the overview of the Earth’s history?

Answer 3

• Formation of the Earth
• The origin of life
• Beginning of plate tectonics
• Oxygenation of Atmosphere (BIF = Banded Iron Formation)
• Snowball Earth
• The Cambrian Explosion
• The Permian-Triassic Extinction-The Permo-Triassic Boundary (“The Great Dying”)
• Pangea
• The Cretaceous-Paleogene Extinction-The Cretaceous-Paleogene Boundary
• Descent Into the Icehouse
• The Anthropocene

Question 4

How was oxygen produced in the atmosphere?

Answer 4

• BIF = Banded Iron Formation

- Oxidation at a redoxcline with biologically produced oxygen

Question 5

What is the take home message from this lecture?

Answer 5

•The Earth is very old, and has gone through extreme changes in its environment over the course of its history •In many cases these changes can be thought of as events that happened fairly rapidly in the context of geologic

Question 6

Key types of change on Earth:

Answer 6

–Extra-terrestrial 
–Tectonics 
–Climate 
–Biology (Evolution)
Some of these changes are mostly random (asteroids), some are mostly cyclical (tectonics, climate), and some are mostly directional (evolution)