What is this Earth 4 billion years ago

What is this? Earth, 4 billion years ago!

The Changing Earth and Atmosphere Learning Objectives: 1. Describe the early Earth and how it was formed 2. Describe the early atmosphere and how it was formed 3. Describe how the Earth and atmosphere have changed over time

What is different about this Early Earth?

Video: Formation of Earth • We are going back to 4. 6 billion years ago. • Watch the video and answer the questions. • Imagine what it would be like to be on the early Earth.

Formation of the Earth 1. How long ago was the Earth formed? 4. 6 billion years ago 2. How did the Earth first form? Rocks collided from gravitational force with such force that they melted and stuck together 3. Describe the conditions of early Earth. Extremely hot, covered in lava, violently volcanic

Formation of the Atmosphere = the envelope of gases surrounding the earth or another planet. 4. How did the first atmosphere form? Volcanic eruptions released gases 5. What gases were in the first atmosphere? Mostly water vapour and carbon dioxide (methane, hydrogen, and ammonia present also) similar to Mars and Venus 6. What vital (to us) gas is missing? Oxygen

Changing Earth 7. What happened when the Earth cooled and the atmosphere became saturated? Water vapour condensed into liquid water (rain) and formed the oceans 8. Describe the conditions of the Earth at this point. Cooled to form thin crust, first oceans 9. Give a brief description of continental drift and plate tectonics.

Atmosphere Today What is the composition of the modern atmosphere? Gas Nitrogen Oxygen Argon Carbon Dioxide Other Percentage 78% 21% 0. 9% 0. 04% Trace

Early Atmosphere (estimate) Other Gases Carbon 10% Dioxide 10% Modern Atmosphere Where does this come from? Carbon Other Argon. Dioxide Gases 0. 09% 0. 03% (Trace) Oxygen 21% Water Vapour 80% Nitrogen 78%

Changing Atmosphere

Photosynthesis Produces Oxygen • The first photosynthetic organisms were able to use the energy from the sun to break down water molecules for energy. Carbon Dioxide + Water Glucose + Oxygen • The oxygen first built up in the oceans, then finally the atmosphere.

Theories About Life • Primordial soup theory states that chemicals in the atmosphere and oceans reacted in the presence of sunlight or lightning to make complex molecules that are the basis for life.

Miller-Urey Experiment • (1953) Tested if early atmosphere and lightning could form complex molecules needed for life • Many amino acids (basis for proteins) formed in the experiment • Supports the primordial soup theory