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The Macroevolutionary Puzzle

The Macroevolutionary Puzzle. Chapter 19. Asteroid Impacts. Many past catastrophic impacts altered the course of evolution K–T boundary 2.3 million years ago in southern Pacific Ocean. Macroevolution.

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The Macroevolutionary Puzzle

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  1. The Macroevolutionary Puzzle Chapter 19

  2. Asteroid Impacts • Many past catastrophic impacts altered the course of evolution • K–T boundary • 2.3 million years ago in southern Pacific Ocean

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

  4. 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

  5. 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

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

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

  8. Quaternary period Geologic Time Scale Phanerozoic eon Cenozoic era 1 Tertiary period 65 Mesozoic era Cretaceous period • Boundaries based on transitions in fossil record 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

  9. 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

  10. 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

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

  12. 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

  13. 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

  14. 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

  15. 1 early reptile 2 3 4 Morphological Divergence 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

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

  17. 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

  18. 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 • Insertion of transposons or gene mutations

  19. Development of Larkspurs • Two closely related species have different petal morphology • They attract different pollinators side view front view D. decorum flower side view front view D. nudicaule flower Figure 19.12Page 314

  20. Development of Larkspurs • Petal difference arises from a change in the rate of petal development 6 D. decorum 4 Petal length (millimeters) 2 D. nudicaule 0 0 10 20 40 Days (after onset of meiosis) Figure 19.12Page 314

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

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

  23. Developmental Changes • Changes in the onset, rate, or time of completion of development steps can cause allometric changes • Adult forms that retain juvenile features

  24. Proportional Changes in Skull Chimpanzee Human Figure 19.14bPage 315

  25. 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

  26. 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

  27. Sequence Conservation • Cytochrome c functions in electron transport • Deficits in this vital protein would be lethal • Long sequences are identical in wheat, yeast, and a primate

  28. Sequence Conservation Yeast Wheat Primate Figure 19.15Page 316-317

  29. 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

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

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

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

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

  34. Phylogeny • The scientific study of evolutionary relationships among species • Practical applications • Allows predictions about the needs or weaknesses of one species on the basis of its known relationship to another

  35. 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

  36. A Cladogram shark mammal crocodile bird feathers fur lungs heart

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

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

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

  40. Taxon Traits (Characters) Jaws Limbs Hair Lungs Tail Shell ConstructingA Cladogram Lamprey - - - - + - Turtle + + - + + + Cat + + + + + - + + + + - - Gorilla Lungfish + - - + + - Trout + - - - + - Human + + + + - - Taxon Traits (Characters) Jaws Limbs Hair Lungs Tail Shell Lamprey 0 0 0 0 0 0 Turtle 1 1 0 1 0 1 Cat 1 1 1 1 0 0 1 1 1 1 1 0 Gorilla Lungfish 1 0 0 1 0 0 Trout 1 0 0 0 0 0 In-text figurePage 320 Human 1 1 1 1 1 0

  41. Constructing a Cladogram trout lungfish turtle cat gorilla human lamprey tail loss hair limbs lungs jaws Figure 19.20ePage 320

  42. 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

  43. Transitional Forms Archaeopteryx Dromaeosaurus

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