1. GENETIC CHANGE IN A POPULATION OVER TIME

2. Types of evidence of evolution  Fossils  Homologies  Anatomical  Molecular  Developmental  Biogeography  Observable Events

3. Fossil Record Helps scientists understand pathway of evolution  Paleontology  Fossil Remains: ex. bone, tooth, or shell Traces: ex. burrow, footprint, or imprint

4. Fossil Record  Most fossils are found in layered sedimentary rock  Oldest fossils are in the lowest layer  Newest fossils are in the top layer

5. Fossil Record  Comparing fossils from different layers shows:  Life on Earth has changes  Increased number of life forms

6. Fossil evidence Reduction of toes over time

7. Anatomical Homologies  Homologous Structures: Similar structure but different function  Shows: Similar genes Common ancestor Turtle Alligator Bird Mammal

8. Anatomical Homologies  Vestigial Structure: Body part reduced in function in a living organism but may have been used in an ancestor  Shows: Organisms evolutionary past Whale pelvis & tailbone humans

9. Developmental Homologies  Shows: Similar genes Common ancestor

10. Fish, reptiles, birds, & mammals (yes, even us!) all have a tail, limb buds & pharyngeal pouches in the early stages of development Developmental Homologies

11. Molecular Homologies  DNA & the genetic code DNA codes for amino acids proteins “Universal” Genetic code The similarity in DNA shows:  A probable common ancestor for all life on Earth

12. Molecular Homologies  The amino acid sequence in a particular protein is compared between organisms. Number of differences from human hemoglobin 45167 8 27 125

13.  Comparing amino acid sequence shows:  Closeness of relationship  A probable common ancestor Molecular Homologies

14.  Amino Acid Sequencing is probably the STRONGEST evidence for relationships among organisms. Amino Acid Difference in Hemoglobin Compared with Human Human hemoglobin has 146 amino acids SpeciesDifferenc e Gorilla 1 Rhesus Monkey 8 Mouse 27 Chicken 45 Frog 67 Lamprey 125

15. What organism belongs at each branch?  CLADOGRAM: diagram that shows the evolutionary relationship among a group of organisms. Number of Amino Acid Differences 150 100 50 0 40 20 30 10 G F E D C B A Common ancestor Where would the common ancestor be? Molecular Homologies

16. Biogeography  Geographic distribution  organisms living far apart may be similar because they share a common ancestor

17. Observable Events  Some changes in species have been observed and studied  Shows: Evolution is an ongoing process Peter & Rosemary Grant’s Study of Beak Size Shift in Darwin’s Finches H. Kettlewell’s Study of Peppered Moth Color Shifts