Chapter 15

1. Chapter 15 0 Tracing Evolutionary History

2. Are Birds Really Dinosaurs with Feathers? • Did birds evolve from dinosaurs? • Evolutionary biologists • Have been pondering this question for decades

3. Recent fossil finds • Support this notion

4. MACROEVOLUTION AND EARTH’S HISTORY • 15.1 The fossil record chronicles macroevolution • The fossil record • Documents the main events in the history of life

5. In the geologic record • Major transitions in life-forms separate eras • Smaller changes divide eras into periods

6. Table 15.1 • The geologic record

7. 15.2 The actual ages of rocks and fossils mark geologic time • Radiometric dating • Measures the decay of radioactive isotopes • Can gauge the actual ages of fossils and the rocks in which they are found

8. Eurasian Plate NorthAmericanPlate ArabianPlate IndianPlate PacificPlate AfricanPlate Splitdeveloping SouthAmericanPlate NazcaPlate AustralianPlate Antarctic Plate Edge of one plate being pushed over edge ofneighboring plate (zones of violent geologic events) Figure 15.3A • 15.3 Continental drift has played a major role in macroevolution • Continental drift • Is the slow, incessant movement of Earth’s crustal plates on the hot mantle

9. 0 Cenozoic Eurasia North America Africa 65 South America India Australia Antarctica Laurasia Millions of years ago 135 Gondwana Mesozoic 245 Pangaea Paleozoic Figure 15.3B • The formation of Pangaea • Altered habitats and triggered extinctions

10. North America Asia Europe Africa South America Australia = Living lungfishes = Fossilized lungfishes • The separation of the continents • Affected the distribution and diversification of organisms Figure 15.3C Figure 15.3D

11. San Andreas Fault North American Plate San Francisco Santa Cruz Pacific Plate Los Angeles California Figure 15.4A, B CONNECTION • 15.4 Tectonic trauma imperils local life • Volcanoes and earthquakes result from plate tectonics • The movements of Earth’s crustal plates

12. 15.5 Mass extinctions were followed by diversification of life-forms • Mass extinctions • Occurred at the end of the Permian and Cretaceous periods

13. NorthAmerica Chicxulubcrater YucatánPeninsula YucatánPeninsula Figure 15.5 • The Cretaceous extinction, which included the dinosaurs • May have been caused by an asteroid

14. A rebound in diversity • Follows mass extinctions

15. PHYLOGENY AND SYSTEMATICS • 15.6 Phylogenies are based on homologies in fossils and living organisms • Phylogeny, the evolutionary history of a group • Is based on identifying homologous and molecular sequences that provide evidence of common ancestry

16. Figure 15.6 • Analogous similarities • Result from convergent evolution in similar environments

17. Systematics • Involves the analytical study of diversity and phylogeny

18. 15.7 Systematics connects classification with evolutionary history • Taxonomists assign a binomial • Consisting of a genus and species name, to each species • A genus • May include a group of related species

19. Felis catus Species Felis Genus Felidae Family Carnivora Order Mammalia Class Chordata Phylum Animalia Kingdom Eukarya Domain • Genera are grouped into progressively larger categories • Family, order, class, phylum, kingdom, and domain Figure 15.7A

20. Felis catus (domestic cat) Lutra lutra (European otter) Canis familiaris (domestic dog) Mephitis mephitis (striped skunk) Canis lupus (wolf) Species Lutra Mephitis Canis Felis Genus Canidae Felidae Mustelidae Family Carnivora Order Figure 15.7B • A phylogenetic tree • Is a hypothesis of evolutionary relationships

21. Taxa Ingroup (Mammals) Outgroup (Reptiles) Duck-billed platypus Eastern box turtle Red kangaroo North American beaver Characters Long gestation Gestation Hair, mammary glands Vertebral column Long gestation 3 3 Gestation 2 2 Hair, mammary glands 1 1 Vertebral column Figure 15.8A • 15.8 Cladograms are diagrams based on shared characters among species • Cladistics uses shared derived characters • To define monophyletic taxa

22. Shared primitive characters • Are common to ancestral groups

23. Snakes Crocodiles Birds Lizards Common reptilian ancestor Figure 15.8B • The simplest (most parsimonious) hypothesis • Creates the most likely phylogenetic tree

24. Asiatic black bear Giant panda Polar bear American black bear Sun bear Sloth bear Spectacled bear Lesser panda Brown bear Raccoon Pleistocene Pliocene 10 Miocene 15 20 Millions of years ago Ursidae 25 Procyonidae 30 Oligocene 35 Common ancestral carnivorans 40 Figure 15.9A • 15.9 Molecular biology is a powerful tool in systematics • Molecular systematics • Develops phylogenetic hypotheses based on molecular comparisons

25. Student Mushroom Tulip Common ancestor Figure 15.9B • Studies of ribosomal RNA sequences • Have shown that humans are more closely related to fungi than to green plants

26. DNA Comparisons • Molecular comparisons of nucleic acids • Often pose technical challenges • Can reveal the most fundamental similarities or differences between species

27. Molecular Clocks • Some regions of DNA • Change at a rate consistent enough to serve as molecular clocks to date evolutionary events

28. Human Chimpanzee Gorilla Orangutan Common ancestor Figure 15.9C • Genome Evolution • Homologous genes • Are found in many species

29. Monera Protista Plantae Fungi Animalia Prokaryotes Earliest organisms Eukoryotes Figure 15.10A • 15.10 Arranging life into kingdoms is a work in progress • In the five-kingdom system • Prokaryotes are in the kingdom Monera • Eukaryotes (plants, animals, protists, and fungi) are grouped in separate kingdoms

30. Bacteria Archaea Eukarya Prokaryotes Earliest organisms Eukoryotes Figure 15.10B • The domain system • Recognizes the prokaryotic domains Bacteria and Archaea • Eukaryotes • Are placed in the domain Eukarya