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The Macroevolutionary Puzzle

The Macroevolutionary Puzzle. Chapter 19. Macroevolution. The large-scale patterns, trends, and rates of change among families and other more inclusive groups of species. Fossils. Recognizable evidence of ancient life What do fossils tell us?

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The Macroevolutionary Puzzle

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  1. The Macroevolutionary Puzzle Chapter 19

  2. Macroevolution The large-scale patterns, trends, and rates of change among families and other more inclusive groups of species

  3. Fossils • Recognizable evidence of ancient life • What do fossils tell us? • Each species is a mosaic of ancestral and novel traits • All species that ever evolved are related to one another by way of descent

  4. Stratification • Fossils are found in sedimentary rock • This type of rock is formed in layers • In general, layers closest to the top were formed most recently

  5. Fossilization • Organism becomes buried in ash or sediments • Organic remains become infused with metal and mineral ions • Carbon 14 dating Figure 19.6Page 309

  6. Radiometric Dating parent isotope in newly formed rock after one half-lives after two half-lives Figure 19.5Page 309

  7. Geologic Time Scale Quaternary period Phanerozoic eon Cenozoic era 1 Tertiary period • Boundaries based on transitions in fossil record 65 Mesozoic era Cretaceous period 138 Jurassic period 205 Triassic period 210 Paleozoic era Permian period 290 Carboniferous period 370 Devonian period 410 Silurian period 435 Ordovician period 505 Cambrian period Cambrian period 570 Proterozoic eon 2,500 mya Figure 19.4 (2)Page 308 Archean eon and earlier

  8. Record Is Incomplete • Fossils have been found for about 250,000 species • Most species weren’t preserved • Record is biased toward the most accessible regions

  9. Continental Drift • Idea that the continents were once joined and have since “drifted” apart • Initially based on the shapes • Wegener refined the hypothesis and named the theoretical supercontinent Pangea

  10. Changing Land Masses 420 mya 260 mya 65 mya 10 mya Figure 19.8cPage 311

  11. Evidence of Movement • Wegener cited evidence from glacial deposits and fossils • Magnetic orientations in ancient rocks do not align with the magnetic poles • Discovery of seafloor spreading provided a possible mechanism

  12. Plate Tectonics • Earth’s crust is fractured into plates • Movement of plates driven by upwelling of molten rock Eurasian plate North American plate Pacific plate Pacific plate African plate South American plate Somali plate Nazca plate Indo-Australian plate Antarctic plate Figure 19.8bPage 311

  13. Comparative Morphology • Comparing body forms and structures of major lineages • Guiding principle: • When it comes to introducing change in morphology, evolution tends to follow the path of least resistance

  14. 1 Morphological Divergence early reptile 2 3 4 5 1 2 3 pterosaur • Change from body form of a common ancestor • Produces homologous structures 4 1 chicken 2 3 1 2 bat 1 3 4 5 porpoise 2 4 5 3 penguin 2 3 1 2 human 3 4 Figure 19.10Page 312 5

  15. Morphological Convergence • Individuals of different lineages evolve in similar ways under similar environmental pressures • Produces analogous structures that serve similar functions

  16. Comparative Development • Each animal or plant proceeds through a series of changes in form • Similarities in these stages may be clues to evolutionary relationships • Mutations that disrupt a key stage of development are selected against

  17. Altering Developmental Programs • Some mutations shift a step in a way that natural selection favors • Small changes at key steps may bring about major differences • gene mutations

  18. Similar Vertebrate Embryos • Alterations that disrupted early development have been selected against FISH REPTILE BIRD MAMMAL Figure 19.13aPage 315

  19. Similar Vertebrate Embryos Aortic arches Adult shark Early human embryo Two-chambered heart Certain veins Figure 19.13bPage 315

  20. Comparative Biochemistry • Kinds and numbers of biochemical traits that species share is a clue to how closely they are related • Can compare DNA, RNA, or proteins • More similarity means species are more closely related

  21. Comparing Proteins • Compare amino acid sequence of proteins produced by the same gene • Human cytochrome c (a protein) • Identical amino acids in chimpanzee protein • Chicken protein differs by 18 amino acids • Yeast protein differs by 56

  22. Nucleic Acid Comparison • Use single-stranded DNA or RNA • Hybrid molecules are created, then heated • The more heat required to break hybrid, the more closely related the species

  23. Molecular Clock • Assumption: “Ticks” (neutral mutations) occur at a constant rate • Count the number of differences to estimate time of divergence

  24. Taxonomy • Field of biology concerned with identifying, naming, and classifying species • Somewhat subjective • Information about species can be interpreted differently

  25. Binomial System • Devised by Carl von Linne • Each species has a two-part Latin name • First part is generic • Second part is specific name

  26. Higher Taxa • Kingdom • Phylum • Class • Order • Family • Inclusive groupings meant to reflect relationships among species

  27. Phylogeny • The scientific study of evolutionary relationships among species

  28. Kingdom Plantae Animalia Animalia Phylum Anthophyta Anthropoda Chordata Class Monocotyledonae Insecta Mammalia Order Poales Diptera Primates Family Poaceae Muscidae Hominidae Genus Zea Musca Homo Species Z. mays M. domestica H. sapiens Examples of Classification corn vanilla orchid housefly human Plantae Anthophyta Monocotyledonae Asparagales Orchidaceae Vanilla V. planifolia Figure 19.17Page 318

  29. Five-Kingdom Scheme • Proposed in 1969 by Robert Whittaker Monera Protista Fungi Plantae Animalia

  30. Three-Domain Classification • Favored by microbiologists EUBACTERIA ARCHAEBACTERIA EUKARYOTES

  31. Six-Kingdom Scheme EUBACTERIA ARCHAEBACTERIA PROTISTA FUNGI PLANTAE ANIMALIA

  32. Evolutionary Tree ANIMALS PLANTS arthropods chordates FUNGI conifers flowering plants annelids round-worms ginkgos sac club echino-derms mollusks fungi fungi cycads horsetails rotifers zygospore- ferns forming flatworms fungi cnidarians lycophytes bryophytes sponges chlorophytes chytrids green algae amoeboid PROTISTANS protozoans (stramenopiles) red brown algae ciliates (alveolates) algae chrysophytes sporozoans oomycotes ? dinoflagellates crown of eukaryotes euglenoids (rapid divergences) slime molds kinetoplastids parabasalids (e.g., Trichomonas) EUBACTERIA spirochetes diplomonads ARCHAEBACTERIA (e.g., Giardia) extreme Gram-positive bacteria chlamydias halophiles methanogens cyanobacteria proteobacteria extreme thermophiles Figure 19.21Page 321 molecular origin of life

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