1. Evolution
Evidences of Change

2. Evidence #1: Fossil Records
Fossils have been found of organisms that no longer exist but they have a striking resemblance to organisms that exist today
Fossils are the remains or traces of organisms that are preserved in sedimentary rocks

3. YOUR TURN!
Look at the rock cycle and create your own definition of sedimentary rock?

4. Evidence #1: Fossil Records
Dating Fossils
Relative dating
does not give an exact age, but a relative age based on its location within the rock record
Law of Superposition = sedimentary layers are deposited with the oldest on the bottom and youngest on top

5. Evidence #1: Fossil Records
Dating Fossils
Carbon-14 dating
age is determined by the amount of radioactive carbon that is in the sample

6. Your Turn!
Look at the rock column, which layer contains the oldest fossils? Explain.
STOP TO COMPLETE THE HORSE FOSSIL ACTIVITY.

7. Evidence #2: Comparative Anatomy
Homologous structures:
Structures may vary in function and appear different, but they all have common skeletal structures
Indicates that the species share a common ancestor

8. Your Turn Which two organisms have a closer common ancestor? Explain.

9. Evidence #2: Comparative Anatomy
Homologous vs. Analogous structures
Analogous Structures have identical function due to similar environmental pressures
DO NOT necessarily have a common ancestor
Ex: Wings in birds and insects

10. Your Turn
Do the organisms below share a common ancestor? Explain why or why not.
STOP AND COMPLETE THE “COMPARATIVE ANATOMY WORKSHEET”

11. Evidence #3: Vestigial Structures
Indicates that the structures were functional in some ancestor of the organism.
Probably shares a common ancestor with an organism that has a functional version of the same feature
Human appendix
Leg bones in whales

12. Vestigial Structure Challenge
Identify each of the following structures as being vestigial or not vestigial in the modern day organism.
If the structure is vestigial, what function did this structure have in the ancient organism.
Appendix
Liver
Coccyx (tail bone)
Skull
Wisdom teeth
Ear muscles
Pectoral muscles
Hair muscles (goose bumps)
Wings in penguins
Pelvic bones in whales
Tiny leg bones in snakes
A third eyelid (nictating membrane)

13. Vestigial Structure Challenge
Appendix – vestigial
Liver – not vestigial
Coccyx (tail bone) – vestigial
Skull – not vestigial
Wisdom teeth – vestigial
Ear muscles – vestigial
Pectoral muscles – not vestigial
Hair muscles (goose bumps) – vestigial
Wings in penguins – not vestigial
Pelvic bones in whales – vestigial
Tiny leg bones in snakes – vestigial
A third eyelid (nictating membrane) – vestigial

14. Evidence #4: Embryology
The early stages of embryonic development of different vertebrates look similar
Similarities fade as development progresses
Indicates that the organisms share a common ancestor

15. Embryo Challenge Stage I: label each embryo Human Hog Calf Fish
Tortoise
Salamander
Rabbit
Chick

16. Embryo Challenge Stage II: label each embryo Human Hog Calf Fish
Tortoise
Salamander
Rabbit
Chick

17. Embryo Challenge Stage III: label each embryo Human Hog Calf Fish
Tortoise
Salamander
Rabbit
Chick

18. Embryo Challenge
Answers:

19. Example Using Embryos of the Following:
Chicken, Cow, Fish, Human, Pig, Rabbit, Salamander, Tortoise

20. Evidence #5: Biochemistry
Compares DNA and protein structure of different organisms
Similarities indicate a common ancestor:
the more they have in common the more closely they are related
STOP AND COMPLETE THE BIOCHEMISTRY ACTIVITY