III. FOSSIL AND BIOCHEMICAL EVIDENCE

2. III. FOSSIL AND BIOCHEMICAL EVIDENCE

3. TYPES 0F FOSSILS PETRIFIED WOOD MOLD CAST BONES AMBER IMPRINTS

4. PALEONTOLOGY -the study of fossils

5. Sedimentary rock

6. Figure 22.18 The Fossil Record • The succession of forms observed in the fossil record is consistent with other inferences about the major branches of descent in the tree of life. • The Darwinian view of life • Predicts that evolutionary transitions should leave signs in the fossil record • Paleontologists • Have discovered fossils of many such transitional forms

7. A. Fossils-relative and absolute dating methods

8. How Rocks and Fossils Are Dated • Sedimentary strata • Reveal the relative ages of fossils Relative Dating Methods

9. Index fossils • Are similar fossils found in the same strata in different locations • Allow strata at one location to be correlated with strata at another location Figure 26.6

10. Accumulating “daughter” isotope 1 2 Ratio of parent isotope to daughter isotope 1 4 Remaining “parent” isotope 1 8 1 16 1 2 3 4 Time (half-lives) Absolute Dating Methods • The absolute ages of fossils • Can be determined by radiometric dating Figure 26.7

11. Another Absolute Dating Method Magnetism Dating • Magnetic reversals of the north and south magnetic poles: • Have occurred repeatedly in the past • Leave their record on rocks throughout the world • These marks are used for dating

12. The GeologicRecord • By studying rocks and fossils at many different sites • Geologists have established a geologic record of Earth’s history

13. B. A Discussion of what can be inferred from patterns in the fossil record • The fossil evidence Is consistent with the idea that today’s organisms evolved from a common ancestor. • There have been catastrophic events that have affected the creation of new species.

14. Geological events that alter environments • Change the course of biological evolution • Conversely, life changes the planet that it inhabits Figure 26.1

15. 3.14 2.4 5.18 7.15 1 6 19 XX 9.12 10.16 13.17 8.11 1 2.19 3.8 4.16 5.14 6.7 13.17 XX 11.12 15.18 9.10 Figure 23.10 Biochemical SimilaritiesBetween Current & Past Species • Biologists also observe homologies among organisms at the molecular level • Such as genes that are shared among organisms inherited from a common ancestor Molecular Homologies

16. Percent of Amino Acids That Are Identical to the Amino Acids in a Human Hemoglobin Polypeptide Species 100% Human Rhesus monkey 95% Mouse 87% Chicken 69% Frog 54% 14% Figure 22.16 Lamprey • Anatomical resemblances among species • Are generally reflected in their molecules, their genes, and their gene products

17. D. Shared Anatomical Structures • Homology • Is similarity resulting from common ancestry • Homologous structures between organisms • Are anatomical resemblances that represent variations on a structural theme that was present in a common ancestor

18. Similar Embryonic Development All VETEBRATES TAIL GILL SLITS

19. Pharyngeal pouches Post-anal tail Chick embryo Human embryo Figure 22.15 • Comparative embryology • Reveals additional anatomical homologies not visible in adult organisms

20. VESTIGIAL STRUCTURES Appendix • Are remnants of structures that served important functions in the organism’s ancestors