1. Evolution
5.2

2. Life consisted of microscopic, single-celled organisms
Earth formed 4.6 BYA
Life came about 4 BYA
Life consisted of microscopic, single-celled organisms
Evolution-change over time-gradually produced the vast complexity and diversity of life today
Evolution

5. We have more evidence now! FOSSILS!
Learning from the past
Origin of Species- Darwin’s book that included evidence of evolution and arguments for natural selection.
We have more evidence now! FOSSILS!

6. The Fossil Record
Fossil- the preserved remains or traces of organisms that lived long ago
Evidence of evolution!
Fossil record- the record of life that unfolded over four billion years

7. How can fossils be preserved?
Petrified remains
Original remains
Molds and casts
Trace fossils
Carbonaceous films

8. Dating
Relative dating- determines which of two fossils is older or younger than the other

9. Dating
Absolute dating- uses the amount of carbon-14 or other radioactive element that remains in a fossil to determine about how long ago a fossilized organism lived

10. Geologic Time Scale
divides Earth’s history into divisions (such as eons, eras, and periods) that are based on major changes in geology, climate, and the evolution of life.