1. EVIDENCE SUPPORTING EVOLUTION
Fossil Evidence & Biogeography
Homologous & Analogous Structures
Vestigial Structures
Embryology
Molecular Comparisons
Microevolution in Action

2. Paleontological Evidence (The Fossil Record)
A record of all fossils ever discovered which demonstrates the changes in organisms’ structures over time
Transitional forms (missing links) have been found to show relationships between ancient forms and modern ones
Fossils can be dated radioactively to determine their age accurately

5. Biogeographical Evidence: Convergent Evolution
Unrelated species living in different regions of the world with similar environmental features happen to look alike (analagous)
Supports natural selection concept: adaptation to environmental factors

6. Biogeographical Evidence
Example: Unrelated anteaters around the world share common features because of their common selective pressures (food, climate, etc…)

7. Comparative Anatomy
Homologous Structures
Structures on different species which are similar in form, but different in function
Structures indicate a shared common ancestor
Example:
The arm bones of various vertebrate organisms

8. Homologous Structures

9. Comparative Anatomy cont…
Analogous Structures
Features that share identical functions and look similar in build due to natural selection
Internal anatomy is very different; organisms are not closely related
Examples: bird and insect wings (i.e. hummingbird & hummingbird moth)

10. Vestigial Structures
Structures that remain on an organism which have no purpose, or are not used for their original purpose anymore
Examples:
Whale/snake hip bones
Ostrich wings
Human tailbone,wisdom teeth, appendix

11. Whales have a pelvis (hip bone) and a femur (upper leg bone) but they have no need for them in the water

12. Flightless birds, like this Cassowary and Ostrich have vestigial wings

13. The human tailbone or coccyx doesn’t do much for us – except hurt if you land on it. These are left-overs from ancestors who used tails for balance or communication like many mammals do today. Some children are born with a full tail (since we have the genes for it). Those who have had to have it surgically removed don’t suffer any negative health effects without it.

14. Human wisdom teeth: the rear molars that most (but not all) people must have removed when they grow in right around age 18. Left-overs from a larger mouth or a byproduct of better modern hygiene?

15. The human appendix: a vestigial organ that is still used by other, mostly herbivorous mammals to help them digest plants in their diet. It is thought to be a leftover from ancestors with a more herbivorous diet. Now it is more a nuisance than anything.
They commonly become infected causing appendicitis and must be surgically removed.

16. Embryological Evidence
Embryos of a different organisms look extremely similar at early stages of development -similarities begin to fade with further development

18. Molecular Evidence
Organisms share a great deal of the same DNA or proteins
The closer an organism is to it’s ancestor, the more molecular similarities exist
Humans/Chimps = 98% the same DNA
Blood proteins in humans & gorillas differ by only one amino acid!
Some genes are almost identical in most of the animal kingdom
One organism’s molecular sequences can work in another organism
Human DNA can make yeast work!

19. Evolution in Action
Kettlewell’s Moths: England’s industrial revolution killed tree lichen and added soot to trees, allowing the population of peppered moths to shift in favor of the black variety (previously rare mutation)

20. Evolution in Action: Speciation

21. Divergent Evolution
Darwin’s Galapagos Finches