Geologic Time Scale

Testing Your Prior Knowledge

See what you know ALREADY!! 1. How old are you? 2. How old is the Earth? 3. When did the dinosaurs become extinct? 4. When did the greatest extinction occur on Earth? 5. Did dinosaurs exist at the same time as humans?

What do you know ALREADY??? 6. In what era do we live? 7. Put these letter on the time line in the best order T = Today B = Beginning of time D = Dinosaurs Became Extinct R = The Oldest Known Rocks H = First Humans D R B T

Now let’s figure out how we did??? Draw a line under what we just did…the next pages are NOTES!

What is the geologic time scale? Time-line of Earth’s history Breaks down Earth’s history into units of time

Eras are the largest unit of time. Ex: Precambrian Paleozoic Mesozoic Cenozoic Eras are divided into smaller parts called periods. Periods are then divided into even smaller parts called epochs.

Era Period Epoch

Precambrian Earliest span of time in Earth’s history. No life for a long time and then very simple life appears. Early life influenced by volcanoes and mountain building

Paleozoic Era Took place after Precambrian. Early invertebrates and amphibians, “Age of Fishes”. Tropical climates allowed growth of new species Mass extinction at end most marine invertebrates disappeared.

Mesozoic Era Took place after Paleozoic Era. Reptiles, small mammals, and small birds. “Age of Reptiles” -dinosaurs, etc Late mass extinction by asteroid or climate change that caused dinosaurs to go extinct.

Cenozoic Era The Era we are currently in!!! Mammals, flowering plants, humans. “Age of Mammals” We still have much diversity but could there be a mass extinction to come???