Aim: How did Earth evolve to support life? How did life evolve? Do Now: Do you think that organisms are more complex now, or were more complex in the past? - What has happened to most organisms on our planet?

I. Evolving Atmosphere - Earliest gasses came from the outgassing of volcanoes. - Consist of water vapor (H2O), carbon dioxide (CO2) and nitrogen (N) - Oxygen we breathe was produced by plants during Photosynthesis. How do you think scientists know about the gasses in our early atmosphere. Where can it be trapped?

II. Evolving Lithosphere - Rocks are the oldest things that are on our planet. (The oldest rocks are found in Canada date to 4.28 Billion years old ( Faux-Amphibolites )) Why are there not more of these rocks found around the planet? What happens to most rock?

III. Evolving Biosphere - Evolution is the gradual change seen in organisms over time - these changes are called variations. - more favorable variations are kept through breeding, and less favorable traits are lost. Darwin’s Theory of Natural Selection

-The fossils record shows us that many of the organisms that lived on Earth are now extinct. - Fossils help show how organisms have changed over time. IV. Evolution and Fossils

“Lucy” Walking completely upright “handy-man” Closest extinct human relative (Neanderthals). We have DNA from this ancestor You and Me