1. INTRODUCTION TO EVOLUTION Honors Biology

2. INTRODUCTION TO EVOLTUION Brainstorm – What is Evolution?

3. OVERVIEW OF EVOLUTION Evolution is a change in species over time Many misconceptions Evolution is a theory Not one or another Overlying theme in Biology Earth is old!

4. HOW DO WE KNOW EVOLUTION EXISTS? Fossils Homologous Structure Vestigial Structures Embryology Similarities in Macromolecules

5. FOSSILS Fossil evidence shows a long history of life on Earth Organisms live, last for awhile and disappeared; new forms live, last and disappear

6. FOSSILS A trace of a long dead organism Many found in sedimentary rock – Sediment deposited by wind or water – Develop from hard elements of body – Minerals replace tissue  fossil

7. FOSSIL Mold: – Imprint in rock that is shape of organism – Cast is a mold filled with hard material Many different types of fossils – Tracks of animals – Mosquito trapped in amber

8. FOSSILS Distribution of fossils – Law of superposition: Layers of strata Lower levels are older; upper levels are newer Relative age of higher up is younger Can also figure absolute age – http://www.pbs.org/wgbh/evolution/library/04/3 /quicktime/l_043_01.html http://www.pbs.org/wgbh/evolution/library/04/3 /quicktime/l_043_01.html

9. FOSSILS Distribution of fossils – Succession of Forms Fossils live and then become extinct Mass extinctions

10. FOSSILS Biogeography – Study of geographical distribution of fossils and living organisms – Fossils in same area as ancestors – Giant fossil kangaroos are found in ________?

11. HOMOLOGOUS AND ANALOGOUS STRUCTURES Homologous Structures: – Similar features – Common ancestor – Forelimbs of vertebrates – Thumbs in primates Analogous Structures: – Similar features – No common ancestor – Dolphins and shark

12. VESTIGIAL STRUCTURES Structures that were once needed and not needed anymore Conserved Examples – Human appendix – Hind limbs in whales – Human tail bone

13. EMBRYOLOGY Similarities in vertebrate embryos Ontogeny recapitulates phylogeny Human embryos have: – Tails – Webbed fingers and toes – Gill slits

14. SIMILARITIES IN MACROMOLECULES Compare DNA, RNA, Amino Acids More recent common ancestor; more in common Hemoglobin of humans and gorillas differ by 1 amino acid; humans and frogs by 67 amino acids DNA of chimps and humans 99% similar (more similar than chimps and gorillas)

15. WHAT DO I KNOW? What is evolution? What are 5 ways we know that evolution exists? Be able to explain/give examples for each form of evolution. What is the difference between a homologous and an analogous trait