Unit 2: Evolution Lesson # 3

12.1: The Fossil Record

Answer the journal question in your notebook

Group Discussion

•  Video Link

• Answer the questions in your lab notebook • What is a paleontologist?

• What do they study?

• What do we use this information for?

Objectives

• Describe the process of permineralization

• Explain the role of isotopes in dating fossils

Perminearlization Fossils

• Key concepts: Permineralization requires rapid burial in an area with water

• Over time, bones in the organism are replaced with minerals

• See page 361

Other Types of Fossils

Other Types of Fossils

What about this guy?

What about this guy?

Relative Dating

No, I don’t mean dating your cousin…

How is Age Determined?

Relative dating

• Estimates when an organism lived by comparing the location of fossils in layers of rock.

• Older organisms are in lower layers, younger organisms are in top layers.

Radiometric Dating

• Key Concept: Radiometric dating is a process that uses the half life of an isotope to calculate the age of a material.

Radiometric Dating

• Video •  Graphing of the half life of class

Com

mon

Iso

tope

s U

sed • Carbon – 14: 5,730 years

• Uranium – 238: 4,468,000,000 years

• Potassium – 40: 1,300,000,000 years

• Uranium – 234: 80,000 years

Radiometric Dating

•  How old is the Earth? •  Which element should we use to date

the Earth?

Time for a Refresher

• How old is the Earth?

• Was early Earth hot or cold? Would you want to live then? Why or why not?

• How are permineralization fossils formed?

• What is a half life?

How to Date a Fossil Activity

• Get into groups of two

• Listen carefully to the instructions

Due Dates

• Geologic Timeline Due TODAY

• How to Date a Fossil Activity is due next class