1. Also Geologic Time Scale and the Origin of Life
Making A Fossil
Also Geologic Time Scale and the Origin of Life

2. Big Bang Approximately 15 bya

6. Relative dating allows paleontologists to estimate a fossil’s age compared with that of other fossils.

7. Basic divisions of the geologic time scale are eras and periods.
Earth’s early atmosphere was made up of hydrogen cyanide, carbon dioxide, carbon monoxide,
nitrogen, hydrogen sulfide, and water.

10. This and other experiments suggested
how simple compounds found on the early Earth
could have combined to form the organic compounds
needed for life.

12. Ancient photosynthetic organisms produced a rise in oxygen in Earth’s atmosphere
Drove some life forms to extinction
Other life forms evolved new, more efficient metabolic pathways that used oxygen for respiration