Prehistoric Life

1. Prehistoric Life What was our planet like a long time ago?

2. Prehistory vs. HistoryWhat is the difference? • Most of the time that people have lived on Earth has been during what we call prehistory. • Today we live during the time period known as history. • When did one end and the other begin? • In one word, WRITING.

3. Prehistory is the time before writing was invented. Prehistory History 4000 BC 2000 BC 1 AD 2000 AD 3500 BC Writing is invented in Mesopotamia

4. How do we know what things were like during prehistoric times? • Fossils • Artifacts

5. What is a fossil? • Physical evidence of former life from a time before recorded human history.

6. How do fossils form? • In order to form, fossils need to have very specific conditions. • Most things do not become fossilized when they die.

7. A fish returns to the place of its birth to spawn (make baby fish).

8. After spawning, the fish dies, becomes waterlogged, and sinks to the bottom.

9. The fish partially decomposes on the sea floor.

10. Unstable rocks below the fish slip and cause sediment (sand, dirt, rotting plants) to quickly cover the fish. Under the sediment, bacteria break down the rest of the fish, leaving just the skeleton.

11. Over time more sediment piles on top, putting weight on the sediment below and turning it to stone.

12. As time goes by the minerals in the skeleton dissolve and are replaced by minerals from the surrounding sediment.

13. Millions of years later, geological forces push the rock towards the surface.

14. Eventually it rises above sea level and the rock begins to erode, exposing the fish’s head.

15. A paleontologist carefully excavates the fossil.

16. What they end up with would look like this.

17. How do we know what things were like during prehistoric times? • Fossils • Artifacts

18. What are prehistoric artifacts?

19. What are prehistoric artifacts?

20. What can artifacts tell us about the past? • The size of spear tips can tell what types of animals people hunted. • Large spear tips were used to hunt large animals like mammoths or deer. • Small spear tips were used to hunt small animals like birds and rabbits.

21. What are the downsides to just using fossils and artifacts to try to determine what prehistoric life was like? • Because there were no written records, archaeologists can only take their best guess when studying fossils and artifacts. • Much of what we know about prehistoric times is just the best guesses of archaeologists. • Some things that people thought 50 years ago have been proven false.

22. How do we know about what happened in the world in the time period we know as history? • Fossils take so long to form that none exist from the time writing was invented. • However, archaeologists still study artifacts. • But now they study them together with oral traditions and written records.

23. What are oral traditions? • Oral traditions are stories about the past that are told and passed from one generation to the next. • In Africa, the storytellers are called griots. • Oral traditions are not always accurate. Sometimes they change as they are told and contain exaggerations.

24. WRITTEN RECORDS • What are written records? • Basically anything can be considered a written record and can be valuable to archaeologists. • For example… • Governmental documents • Tomb walls • Business contracts • Religious documents • Copies of speeches made by leaders • Work done by a student in school

25. Imagine, 5,000 years from now someone could be studying your homework to get an idea of what your life is like.