Unveiling Earth's History: Geologic Time Scale Exploration

1. Chapter 21 Fossils and the Fossil Record

2. As you travel down the a canyon, you travel back in time. Each layer of rock records climate at the time that the rock was laid down. S 21.1 The Geologic Time Scale

3. The Grand Canyon is made of a number of layers

5. The Geologic Time Scale – a record that uses fossils in the rock to establish the age of the rock Divided into 1. Eons – 10 9 (Archaen, Proterozoic and Phanerozoic) 2. Eras – 108 – 10 9 years Paleozoic Era = old life, Mesozoic Era = Middle life Cenozoic Era = new life

6. 3. Periods – 107 – 108 years - named for geographic regions which contain rocks of that age. ex Jurassic period = Jura Mnts, Mississippian Period = cliffs on the Mississippi 4. Epochs – 106 – 107 years

7. History of the Earth Oldest: Precambrian time a. Archean Eon – only bacteria and stromatolites. b. Proterozoic Eon – only soft bodied marine animals Newer: c. Pharnerozoic Eon – hard-shelled life forms evolve and larger plants and animals NOTE: There is a major extinction at the end of each ERA

8. Using the chart on page 554, you are now going to construct Geologic Time Scale Directions: 1. Choose a Period or Epoch 2. Write its name and time on a sheet of paper. Use Marker and be neat • Arrange Names in the correct order and in the correct proportionate location. Yes this takes math. • Write what geological event happened during it. • Find drawings or photographs of organisms that is an indicator species (plant and animal) of this period of time and attach it to your Epoch or period