Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
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? – Each species is a mosaic of ancestral and novel traits – All species that ever evolved are related to one another by way of descent 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 Fossilization • Organism becomes buried in ash or sediments • Organic remains become infused with metal and mineral ions • Carbon 14 dating Figure 19.6 Page 309 Radiometric Dating parent isotope in newly formed rock after one half-lives after two half-lives Figure 19.5 Page 309 Geologic Time Scale • Boundaries based on transitions in fossil record Phanerozoic eon Cenozoic era Mesozoic era Quaternary period 1 Tertiary period 65 Cretaceous period 138 Jurassic period Triassic period Paleozoic era 205 210 Permian period 290 Carboniferous period 370 Devonian period Silurian period Ordovician period Cambrian Cambrianperiod period 410 435 505 570 Proterozoic eon Figure 19.4 (2) Page 308 Archean eon and earlier 2,500 mya 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 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 Changing Land Masses 420 mya 260 mya 65 mya 10 mya Figure 19.8c Page 311 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 Plate Tectonics • Earth’s crust is fractured into plates • Movement of plates driven by upwelling of molten rock Eurasian plate North Pacific plate American plate Pacific plate African plate Nazca plate South American plate Somali plate IndoAustralian plate Antarctic plate Figure 19.8b Page 311 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 Morphological Divergence 4 5 21 3 • Change from body form of a common ancestor • Produces homologous structures 4 Page 312 pterosaur 1 chicken 2 3 1 2 bat 3 4 1 5 porpoise 2 4 3 5 penguin 2 1 Figure 19.10 3 early reptile 21 2 3 4 5 3 human Morphological Convergence • Individuals of different lineages evolve in similar ways under similar environmental pressures • Produces analogous structures that serve similar functions 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 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 Similar Vertebrate Embryos • Alterations that disrupted early development have been selected against FISH REPTILE BIRD MAMMAL Figure 19.13a Page 315 Similar Vertebrate Embryos Adult shark Aortic arches Two-chambered heart Certain veins Early human embryo Figure 19.13b Page 315 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 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 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 Molecular Clock • Assumption: “Ticks” (neutral mutations) occur at a constant rate • Count the number of differences to estimate time of divergence Taxonomy • Field of biology concerned with identifying, naming, and classifying species • Somewhat subjective • Information about species can be interpreted differently Binomial System • Devised by Carl von Linne • Each species has a two-part Latin name • First part is generic • Second part is specific name Higher Taxa • • • • • Kingdom Phylum Class Order Family • Inclusive groupings meant to reflect relationships among species Phylogeny • The scientific study of evolutionary relationships among species Examples of Classification corn Kingdom Phylum Class Order Family Genus Species Plantae Anthophyta Monocotyledonae Poales Poaceae Zea Z. mays vanilla orchid Plantae Anthophyta Monocotyledonae Asparagales Orchidaceae Vanilla V. planifolia housefly Animalia Anthropoda Insecta Diptera Muscidae Musca M. domestica human Animalia Chordata Mammalia Primates Hominidae Homo H. sapiens Figure 19.17 Page 318 Five-Kingdom Scheme • Proposed in 1969 by Robert Whittaker Monera Protista Fungi Plantae Animalia Three-Domain Classification • Favored by microbiologists EUBACTERIA ARCHAEBACTERIA EUKARYOTES Six-Kingdom Scheme EUBACTERIA ARCHAEBACTERIA PROTISTA FUNGI PLANTAE ANIMALIA Evolutionary Tree PLANTS flowering plants conifers ginkgos cycads horsetails ferns FUNGI sac club fungi fungi zygosporeforming fungi lycophytes ANIMALS arthropods chordates annelids roundechinomollusks worms derms rotifers flatworms cnidarians bryophytes chlorophytes (stramenopiles) brown algae chrysophytes oomycotes sponges chytrids green algae amoeboid protozoans red algae slime molds ? crown of eukaryotes (rapid divergences) PROTISTANS ciliates (alveolates) sporozoans dinoflagellates euglenoids kinetoplastids parabasalids (e.g., Trichomonas) ARCHAEBACTERIA diplomonads extreme (e.g., Giardia) Gram-positive bacteria halophiles methanogens cyanobacteria extreme thermophiles molecular origin of life EUBACTERIA spirochetes chlamydias proteobacteria Figure 19.21 Page 321