1. Evidence For Evolution
Fossil Record
Biogeography
Homologous Structures
Vestigial Structures
Comparative Embryology
Molecular Evidence
Imperfections of Adaptations

2. Deposited last, newest fossils deposited first, oldest fossils
Rocks formed by layers (sediments) settling on top are called sedimentary.
Newest Layers
Deposited last, newest fossils
Oldest Layers
deposited first, oldest fossils

3. Geologists can determine just how old each layer is
Most of these layers are sedimentary rock.
Geologists can determine just how old each layer is
Fossils are within that time period

4. The Fossil Record of Horses
Record shows size and shape progression
Used to be as small as dogs!

5. Some fossils are simply older versions of insects much like those found on Earth today

6. The Fossil Record A story we piece together as we find new fossils
Clearly, the fossil record tells us of times when life on Earth was very different than it is today
The story tells us life has gradually become more complex.
Fossil of cells that resemble modern cyanobacteria (3.5 billion years old)
a very scary salamander

7. Biogeography
The distribution of different organisms around the planet Biogeography Video (7:03)

8. What is similar between these different animals?
These 3 organisms live in similar environments around the world
(the US, Australia, and Argentina)
What is similar between these different animals?
jack rabbit (a lagamorph) kangaroo (a marsupial) patagonian hare (a rodent)

9. Homologous Structures
Structures used for different purposes that indicate a common ancestry Why would appendages used for different purposes have the same underlying bone structure?

10. Vestigial Structures Structures that have no function in the organism
The only explanation is that they are remnants of evolution
Human Appendix
Human Tail Bone
Snake Spurs
Whale Hips

11. Comparative Embryology
Turtle
Mouse
Human
Chick
Pig
Can you tell which is which?
mouse, turtle, chick, pig, and human
Why would all these very different organisms need to develop the same way?

12. Molecular Evidence
Compare DNA sequences of different organisms to see how similar they are!
% Similarity Between Species

13. Human DNA? 96% similar to chimpanzee 85% mouse 50% fruit flies
Just as DNA shows you descended from your parents it also shows you descended from the grandparent of them all ~3.8 billion yrs ago

14. Imperfections of Adaptations
The Panda’s Thumb
Eats bamboo, not meat
Developed thumb grasp bamboo
Not a perfect solution, but it works!

15. Important Points To Remember About The Process of Evolution

16. Evolution acts on populations not individuals
Individual organisms do not improve themselves
Nature selects the best of the members of a population to survive and produce the next generation

17. Mutations may produce such unique features but selection enhances them
Evolution does not produce new adaptations!
It amplifies (increases) or diminishes (decreases) variations that are already present
Mutations may produce such unique features but selection enhances them