1. Fossils

2. What is a fossil? A fossil is the preserved remains of a once-living organism.

3. A fossil may be: an original skeleton or shell; a mold or cast; material that has replaced the once living thing; traces such as footprints or worm tubes

4. What are the fossil types? Body fossils – actual parts of an organism, unaltered or altered bones, shells, leaf imprints Trace fossils – evidence of life that is not a body fossil tracks, burrows, casts

5. Body fossils

6. Trace Fossils

7. More on trace fossils Tracks – impressions of passage of living things

8. Fossil records document the course of life through time Fossil Evidence of Evolution

9. 9 Fossils document evolutionary transition The oldest known bird fossil is the Archaeopteryx It is intermediate between bird and dinosaur Possesses some ancestral traits and some traits of present day birds Archaeopteryx was first found in 1859 Fossil Evidence of Evolution

10. 10 Fossil of Archaeopteryx Fossil Evidence of Evolution

11. 11 Recent discoveries –Four-legged aquatic mammal Important link in the evolution of whales and dolphins from land-dwelling, hoofed ancestors –Fossil snake with legs –Tiktaalik: a species that bridged the gap between fish and the first amphibian Fossil Evidence of Evolution

12. 12 Whale “missing links” Fossil Evidence of Evolution

13. 13 Homology of the bones of the forelimb of mammals Anatomical Evidence for Evolution