1. Time For Change The Geologic Time Scale

2. Do Now 4/29/13 Key Question: How long do you think organisms have been living on Earth? Initial Thoughts:

3. Evidence: Notes & Timeline Watch the power point and jot down the major events. This will help you arrange periods of time in the correct order. With a partner, read the information on the 6 time cards and arrange them with the oldest on the left and the most recent on the right. Record the order you placed the card on your table.

4. Evidence: Check Yourself Card E 1.6 mya = Cenozoic Era, end of Tertiary Period A65 mya = end of Mesozoic Era C251 mya = end of Paleozoic D543 mya = beginning of Paleozoic F543 mya = End of Pre-Cambrian Era B 4.6 Bya = beginning of Pre-Cambrian Era (4.6 Bya = 4,600 Mya)

5. Time Line Instructions 100 cm strip of paper and the Major Divisions in Geologic Time sheet Construct a time line of the last 4.5 billion years. Draw a 90 cm horizontal line. Convert and fill in the table. 1 cm = 50 million years. (Million years divided by 50) Draw a vertical line at the left end of the paper and label it The Origin of Earth. Remember: 4.6 billion years = 4,600 million years.

6. Time Line Instructions Label each time span with it’s name and each boundary with its defining event. Fill in along the time line the notable fossils found during that Era Add single-celled bacteria at 3.5 bya Add multi-celled organisms at 1.4 bya Add color and embellishments, and don’t forget your name and period.

7. Time Line Instructions Fill in along the time line the notable fossils found during that Era Add single-celled bacteria at 3.5 bya Add multi-celled organisms at 1.4 bya Add color and embellishments, and don’t forget your name and period.

8. Analysis Questions 1.How do you think scientists decide to divide geologic time into its periods? 2. What fraction of the 90 cm time line does the Pre-Cambrian time take up? 3.What fraction of Earth’s History have a)Single celled organisms lived on our planet? b)Mammals lived on our planet

9. Summary What did you think about how long species have been living on this earth before this lesson? What did you learn about how long species have been living on this earth from this lesson? (Minimum of 3 sentences!!!) What are some further thoughts or questions you have about how long species have been living on this earth?

10. Reflection Put the following in a time line: I started 4 th grade I ate or drank something I learned to walk I woke up I was born I took a breath I started kindergarten I learned to read My parents were born  Write number of years ago  Place it on a time line  Think of a major event in your life that is important to you.  Use this event to divide your time scale into 2 periods by drawing a horizontal line.  Name the 2 periods you just created