1. Fossils
Bell Ringer: Welcome to a new semester! Write down a personal goal for yourself in this class for the new semester.

2. Fossils are remains of organisms preserved in the Earth
What are fossils?
Fossils are remains of organisms preserved in the Earth

3. Fossil Examples

4. How Do Things Become Fossils?
Bill Bryson excerpt “Goes On” introduction
While I am reading, write down 3 interesting facts you did not know before

5. How Do Things Become Fossils?
An organism must die and be preserved very quickly
This means that all the soft tissue parts must be preserved before anything eats it or bacteria decomposes it
It is very difficult for an organism to become a fossil

6. Types of Fossils Mineralization Carbonization Molds and Casts
Trace Fossils (ex: footprints)
Original organism (ex: insects in amber)

7. Fossil Record
The fossil record is all the fossils ever discovered on Earth
Together this fossil record shows us thousands of species that once existed
Though we have many fossils, there are more that have not been discovered and even more that never made it into the fossil record
Question: What does it mean when something “didn’t make it into the fossil record?”

8. How Do We Date Fossils?

9. How Do We Date Fossils?
Relative Dating – scientists estimate the age of a fossil based on how old the surrounding rocks are. The deeper down the fossil was found, the older it is.
Absolute Dating – scientists use isotopes (unstable elements) to date a fossil. Carbon-14 dating is one kind.

10. Bell Ringer: What are two ways we date fossils?
Geologic Time
Bell Ringer: What are two ways we date fossils?
Also, take out your bathroom passes if you would like extra credit for them.

11. Putting Things in Order: Life on Earth
Everyone will work with their shoulder partner to place the events in order
Be prepared to defend your decisions!

12. Putting Things in Order
What is the general trend?
How did you determine the order?

13. The Correct Order The first life on Earth appears
Seaweed and aquatic invertebrates appear
First plants move onto land
The first amphibians appear
The first reptiles appear
The dinosaurs appear
The dinosaurs go extinct
Birds and mammals flourish
The first human appear
The earliest written record of humans

14. All of Life in One Day
With the same shoulder partner, imagine all those events happened in one day
If the first organism appeared at midnight (12:00 am) when would every other event have happened?
Make your best estimates on your own paper for each event

15. The Correct Times The first life on Earth appears- midnight
Seaweed and aquatic invertebrates appear- 4:30 PM
First plants move onto land- 6:45 PM
The first amphibians appear- 7:50 PM
The first reptiles appear- 9:00 PM
The dinosaurs appear- 9:30 PM
The dinosaurs go extinct- 11:00 PM
Birds and mammals flourish- 11:01 PM
The first human appear- 11:59:58 PM
The earliest written record of humans- 11:59:59:75 PM

16. Life on Earth Life has been on Earth for a really long time!
The fossil record shows us there were some really strange organisms that aren’t around anymore

17. Extinction
Bell Ringer: In the past two days we have been learning about fossils and geologic time. Tell me the most interesting thing you learned.

18. Deinotherium
Dunkleosteus
Hallucigenia
Archeopteryx

19. Where Did They Go? 99.9% of organisms that ever existed are extinct
Some were killed off by humans or human activities
Others died in large disasters (like the dinosaurs)
But how do we account for all the other species that went extinct?

20. Cell Phone “Extinction”
Let’s look at cell phones that are no longer used- thus are “extinct”
Consider the reasons these cell phones aren’t used anymore

21. 1989
1983
1994
1996
2004
2008
1999
2006

22. Cell Phone “Extinction”
Why are we not using the same clunky cell phones from 1983?
What trends do you see in cell phones development?
What kinds of things might you expect to see in the future? Why?
What is the driving pressure behind these changes in cell phones?

23. Extinction
Things go extinct because their environment changes and they cannot compete
For example, now that we can access the internet from our phones, our environment is one that expects getting on the internet from the phones. So big clunky phones cannot compete.

24. Quick Write
Take 2 minutes to talk to your shoulder partner and finish this statement:
“Fossils are like _____________________________”
(There is not right or wrong answer to this question. Example: Fossils are like books of history scientists can read.)