1. Evolution WHAT IS THE THEORY OF EVOLUTION &
WHAT EVIDENCE SUPPORTS THE THEORY EVOLUTION?

2. THE THEORY OF EVOLUTION
Evolution: The process of gradual (slow) change over time
All species on earth evolved from a common ancestor
Simple life forms evolve into more complex ones

3. 4 WAYS TO STUDY EVOLUTION:
Geologic Record (Fossils)
Comparative Anatomy
Comparative Embryology
Comparative Biochemistry (DNA)

4. 1) Geologic Record Earth’s “Timeline” Earth is 4-5 Billion years old!
Fossils: preserved remains of an organism that indicate how long ago it existed
Carbon Dating tells the age of a fossil
Layer of rock indicates age of fossil (lower in rock layers = older fossils)
Age of Earth

6. 2) Comparative Anatomy Anatomy = body structure of an organism
Homologous Structures: similar in structure; different in function.
Example: Arm of Human & Flipper of Seal
Analogous Structures: similar in function; different in structure.
Example: Wing of Bird & Wing of Bee

10. Q: Which limbs represent homologous structures?
Q: Which limbs represent analogous structures?

11. 3) Comparative Embryology
Embryology = study of embryos (developing babies)
Similarities between embryos proves a common ancestor
The later in development the embryos are similar = the more closely related the organisms are

12. Q: What evidence suggests that all 4 organisms have a common ancestor?
Q: Which organism is the Turtle MOST CLOSELY RELATED to? How do you know?

13. 4) Comparative Biochemistry (DNA)
Comparing the chemicals that make up an organism, especially their DNA.
More similarities in DNA = more closely related
Human DNA A-G-G-C-A-T-A-A-A-C-C-A-A-C-C-G-A-T-T-A
Chimpanzee DNA A-G-G-C-C-C-C-T-T-C-C-A-A-C-C-G-A-T-T-A
Gorilla DNA A-G-G-C-C-C-C-T-T-C-C-A-A-C-C-A-G-G-T-A

14. Which do you think is the most important/most accurate?
Geologic Record (Fossils)
Comparative Anatomy
Comparative Embryology
Comparative Biochemistry (DNA)

15. COMPARING THE DNA IS THE MOST ACCURATE WAY TO SHOW EVOLUTIONARY RELATIONSHIPS