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  • Figure 14.1 Two patterns of evolution
  • Figure 14.2a Similarity between different species
  • Figure 14.2b Diversity within one specie
  • Figure 14.3 Reproductive barriers between closely related species
  • Figure 14.4a Temporal isolation
  • Figure 14.4b Habitat isolation
  • Figure 14.4c Behavioral isolation
  • Figure 14.4d Mechanical isolation
  • Figure 14.4e Gametic isolation
  • Figure 14.3 Reproductive barriers between closely related species
  • Figure 14.5a Reduced hybrid viability
  • Figure 14.5b Reduced hybrid fertility
  • Figure 14.5c Hybrid breakdown
  • Figure 14.7 Allopatric speciation of antelope squirrels on opposite rims of the Grand Canyon
  • Figure 14.10 Two models for the tempo of evolution
  • Figure 14.14a Petrified wood
  • Figure 14.14b Insect fossil in amber
  • Figure 14.14c Dinosaur bone
  • Figure 14.14d Dinosaur footprints
  • Table 14.1 The Geologic Time Scale
  • Figure 14.15 Radiometric dating
  • Figure 14.16 California's San Andreas fault
  • Figure 14.17 The history of plate tectonics
  • Figure 14.19a Leopard (Panthera pardus)
  • Figure 14.19b Tiger (Panthera tigris)
  • Figure 14.19c Lion (Panthera leo)
  • Figure 14.19d Jaguar (Panthera onca)
  • Figure 14.20 Hierarchical classification
  • Figure 14.21 The relationship of classification and phylogeny for some members of the order Carnivora
  • Figure 14.23 A simplified example of cladistics
  • Figure 14.25 The three-domain classification system
  • Figure 14.26 The increase in mammalian diversity after the extinction of dinosaurs
  • 14 lecture presentation0

    1. 1. © 2010 Pearson Education, Inc. MACROEVOLUTION AND THE DIVERSITY OF LIFE • Macroevolution: – Encompasses the major biological changes evident in the fossil record – Includes the formation of new species
    2. 2. © 2010 Pearson Education, Inc. • Speciation: – Is the focal point of macroevolution – May occur based on two contrasting patterns
    3. 3. © 2010 Pearson Education, Inc. • In nonbranching evolution: – A population transforms but – Does not create a new species Video: Galápagos Islands Overview
    4. 4. © 2010 Pearson Education, Inc. • In branching evolution, one or more new species branch from a parent species that may: – Continue to exist in much the same form or – Change considerably
    5. 5. Branching Evolution (results in speciation) Nonbranching Evolution (no new species) PATTERNS OF EVOLUTION Figure 14.1
    6. 6. © 2010 Pearson Education, Inc. THE ORIGIN OF SPECIES • Species is a Latin word meaning: – “Kind” or – “Appearance.”
    7. 7. © 2010 Pearson Education, Inc. What Is a Species? • The biological species concept defines a species as – “A group of populations whose members have the potential to interbreed and produce fertile offspring”
    8. 8. Similarity between different species Figure 14.2a
    9. 9. Diversity within one species Figure 14.2b
    10. 10. © 2010 Pearson Education, Inc. Reproductive Barriers between Species • Prezygotic barriers prevent mating or fertilization between species. Video: Blue-footed Boobies Courtship Ritual Video: Albatross Courtship Ritual Video: Giraffe Courtship Ritual
    11. 11. VIABLE, FERTILE OFFSPRING Hybrid breakdown FERTILIZATION (ZYGOTE FORMS) INDIVIDUALS OF DIFFERENT SPECIES MATING ATTEMPT Reduced hybrid fertility Reduced hybrid viability Temporal isolation Habitat isolation Behavioral isolation Mechanical isolation Gametic isolation Prezygotic Barriers Postzygotic Barriers Figure 14.3
    12. 12. © 2010 Pearson Education, Inc. • Prezygotic barriers include: – Temporal isolation – Habitat isolation – Behavioral isolation – Mechanical isolation – Gametic isolation
    13. 13. Temporal Isolation Skunk species that mate at different times Figure 14.4a
    14. 14. Habitat Isolation Garter snake species from different habitats Figure 14.4b
    15. 15. Mating ritual of blue-footed boobies Behavioral Isolation Figure 14.4c
    16. 16. Mechanical Isolation Snail species whose genital openings cannot align Figure 14.4d
    17. 17. Sea urchin species whose gametes cannot fuse Gametic Isolation Figure 14.4e
    18. 18. © 2010 Pearson Education, Inc. • Postzygotic barriers operate if: – Interspecies mating occurs and – Hybrid zygotes form
    19. 19. © 2010 Pearson Education, Inc. VIABLE, FERTILE OFFSPRING Hybrid breakdown FERTILIZATION (ZYGOTE FORMS) INDIVIDUALS OF DIFFERENT SPECIES MATING ATTEMPT Reduced hybrid fertility Reduced hybrid viability Temporal isolation Habitat isolation Behavioral isolation Mechanical isolation Gametic isolation Prezygotic Barriers Postzygotic Barriers Figure 14.3
    20. 20. © 2010 Pearson Education, Inc. • Postzygotic barriers include: – Reduced hybrid viability – Reduced hybrid fertility – Hybrid breakdown
    21. 21. Frail hybrid salamander offspring Reduced Hybrid Viability Figure 14.5a
    22. 22. Reduced Hybrid Fertility Mule (sterile hybrid of horse and donkey) Donkey Mule Horse Figure 14.5b
    23. 23. Hybrid Breakdown Sterile next-generation rice hybrid Figure 14.5c
    24. 24. © 2010 Pearson Education, Inc. Mechanisms of Speciation • A key event in the potential origin of a species occurs when a population is severed from other populations of the parent species.
    25. 25. © 2010 Pearson Education, Inc. • Species can form by: – Allopatric speciation, due to geographic isolation
    26. 26. © 2010 Pearson Education, Inc. Video: Grand Canyon Allopatric Speciation • Geologic processes can: – Fragment a population into two or more isolated populations – Contribute to allopatric speciation Video: Volcanic Eruption Video: Lava Flow
    27. 27. Ammospermophilus harrisii Ammospermophilus leucurus Figure 14.7
    28. 28. © 2010 Pearson Education, Inc. • Speciation occurs only with the evolution of reproductive barriers between the isolated population and its parent population.
    29. 29. © 2010 Pearson Education, Inc. What Is the Tempo of Speciation? • There are two contrasting models of the pace of evolution: – The gradual model, in which big changes (speciations) occur by the steady accumulation of many small changes – The punctuated equilibria model, in which there are – Long periods of little change, equilibrium, punctuated by – Abrupt episodes of speciation
    30. 30. Punctuated model Graduated model Time Figure 14.10
    31. 31. © 2010 Pearson Education, Inc. EARTH HISTORY AND MACROEVOLUTION • Macroevolution is closely tied to the history of the Earth.
    32. 32. © 2010 Pearson Education, Inc. Geologic Time and the Fossil Record • The fossil record is: – The sequence in which fossils appear in rock strata – An archive of macroevolution
    33. 33. Figure 14.14a
    34. 34. Figure 14.14b
    35. 35. Figure 14.14c
    36. 36. Figure 14.14d
    37. 37. © 2010 Pearson Education, Inc. • Geologists have established a geologic time scale reflecting a consistent sequence of geologic periods. Animation: Macroevolution Animation: The Geologic Record
    38. 38. Table 14.1
    39. 39. © 2010 Pearson Education, Inc. • Fossils are reliable chronological records only if we can determine their ages, using: – The relative age of fossils, revealing the sequence in which groups of species evolved, or – The absolute age of fossils, requiring other methods such as radiometric dating
    40. 40. © 2010 Pearson Education, Inc. • Radiometric dating: – Is the most common method for dating fossils – Is based on the decay of radioactive isotopes – Helped establish the geologic time scale
    41. 41. Carbon-14 in shell Time (thousands of years) Radioactive decay of carbon-14 How carbon-14 dating is used to determine the vintage of a fossilized clam shell Carbon-14radioactivity (as%oflivingorganism’s C-14toC-12ratio) 100 75 0 50 25 0 5.6 50.411.2 16.8 22.4 28.0 33.6 39.2 44.8 Figure 14.15
    42. 42. © 2010 Pearson Education, Inc. Plate Tectonics and Macroevolution • The continents are not locked in place. Continents drift about the Earth’s surface on plates of crust floating on a flexible layer called the mantle. • The San Andreas fault is: – In California – At a border where two plates slide past each other
    43. 43. Figure 14.16
    44. 44. © 2010 Pearson Education, Inc. • About 250 million years ago: – Plate movements formed the supercontinent Pangaea – The total amount of shoreline was reduced – Sea levels dropped – The dry continental interior increased in size – Many extinctions occurred
    45. 45. Pangaea Present PaleozoicCenozoicMesozoic 251millionyearsago13565 Laurasia Gondwana Eurasia India Madagascar North America Africa South America Antarctica Australia Figure 14.17
    46. 46. © 2010 Pearson Education, Inc. • About 180 million years ago: – Pangaea began to break up – Large continents drifted increasingly apart – Climates changed – The organisms of the different biogeographic realms diverged
    47. 47. © 2010 Pearson Education, Inc. • Plate tectonics explains: – Why Mesozoic reptiles in Ghana (West Africa) and Brazil look so similar – How marsupials were free to evolve in isolation in Australia
    48. 48. Mass Extinctions and Explosive Diversifications of Life • The fossil record reveals that five mass extinctions have occurred over the last 600 million years. • The Permian mass extinction: – Occurred at about 250 million years ago – Claimed about 96% of marine species © 2010 Pearson Education, Inc.
    49. 49. © 2010 Pearson Education, Inc. • The Cretaceous extinction: – Occurred at the end of the Cretaceous period, about 65 million years ago – Included the extinction of all the dinosaurs except birds – Permitted the rise of mammals
    50. 50. © 2010 Pearson Education, Inc. CLASSIFYING THE DIVERSITY OF LIFE • Systematics focuses on: – Classifying organisms – Determining their evolutionary relationships • Taxonomy is the: – Identification of species – Naming of species – Classification of species
    51. 51. © 2010 Pearson Education, Inc. Some Basics of Taxonomy • Scientific names ease communication by: – Unambiguously identifying organisms – Making it easier to recognize the discovery of a new species • Carolus Linnaeus (1707–1778) proposed the current taxonomic system based upon: – A two-part name for each species – A hierarchical classification of species into broader groups of organisms
    52. 52. © 2010 Pearson Education, Inc. Naming Species • Each species is assigned a two-part name or binomial, consisting of: – The genus – A name unique for each species • The scientific name for humans is Homo sapiens, a two part name, italicized and latinized, and with the first letter of the genus capitalized.
    53. 53. © 2010 Pearson Education, Inc. Hierarchical Classification • Species that are closely related are placed into the same genus.
    54. 54. Leopard (Panthera pardus) Figure 14.19a
    55. 55. Tiger (Panthera tigris) Figure 14.19b
    56. 56. Lion (Panthera leo) Figure 14.19c
    57. 57. Jaguar (Panthera onca) Figure 14.19d
    58. 58. © 2010 Pearson Education, Inc. • The taxonomic hierarchy extends to progressively broader categories of classification, from genus to: – Family – Order – Class – Phylum – Kingdom – Domain
    59. 59. Leopard (Panthera pardus) Species Panthera pardus Genus Panthera Family Felidae Order Carnivora Class Mammalia Phylum Chordata Kingdom Animalia Domain Eukarya Figure 14.20
    60. 60. © 2010 Pearson Education, Inc. Classification and Phylogeny • The goal of systematics is to reflect evolutionary relationships. • Biologists use phylogenetic trees to: – Depict hypotheses about the evolutionary history of species – Reflect the hierarchical classification of groups nested within more inclusive groups
    61. 61. Panthera pardus (leopard) SpeciesGenus Felidae Order Carnivora Family Canis Lutra Panthera Mephitis Canidae Mustelidae Canis lupus (wolf) Canis latrans (coyote) Lutra lutra (European otter) Mephitis mephitis (striped skunk) Figure 14.21
    62. 62. © 2010 Pearson Education, Inc. Cladistics • Cladistics is the scientific search for clades. • A clade: – Consists of an ancestral species and all its descendants – Forms a distinct branch in the tree of life
    63. 63. Hair, mammary glands Long gestation Gestation Duck-billed platypus Iguana Outgroup (reptile) Ingroup (mammals) Beaver Kangaroo Figure 14.23
    64. 64. © 2010 Pearson Education, Inc. Classification: A Work in Progress • Linnaeus: – Divided all known forms of life between the plant and animal kingdoms – Prevailed with his two-kingdom system for over 200 years • In the mid-1900s, the two-kingdom system was replaced by a five-kingdom system that: – Placed all prokaryotes in one kingdom – Divided the eukaryotes among four other kingdoms
    65. 65. © 2010 Pearson Education, Inc. • In the late 20th century, molecular studies and cladistics led to the development of a three-domain system, recognizing: – Two domains of prokaryotes (Bacteria and Archaea) – One domain of eukaryotes (Eukarya) Animation: Classification Schemes
    66. 66. Kingdom Animalia Domain ArchaeaEarliest organisms Domain Bacteria Domain Eukarya Kingdom Fungi Kingdom Plantae The protists (multiple kingdoms) Figure 14.25
    67. 67. Evolution Connection: Rise of the Mammals • Mass extinctions: – Have repeatedly occurred throughout Earth’s history – Were followed by a period of great evolutionary change © 2010 Pearson Education, Inc.
    68. 68. © 2010 Pearson Education, Inc. • Fossil evidence indicates that: – Mammals first appeared about 180 million years ago – The number of mammalian species – Remained steady and low in number until about 65 million years ago and then – Greatly increased after most of the dinosaurs became extinct
    69. 69. American black bear Eutherians (5,010 species) Millions of years ago Monotremes (5 species) Marsupials (324 species) Ancestral mammal Reptilian ancestor Extinction of dinosaurs 250 200 150 100 5065 0 Figure 14.26

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