Whale evolution
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    Whale evolution Whale evolution Presentation Transcript

    • Whale Evolution By Goua Vang Evolution
    • Outline
      • General Information
      • Father of whale evolution
      • Evidence
        • --Morphological evidence
        • -molecular biological evidence
        • -Geochemical evidence
        • -other evidence*
      • Step of evolution
      • Conclusion
    • General information
      • What is a whale?
        • -Mammal
        • -Warm-blooded vertebrate
          • Metabolism*
        • -Female
          • bear live young
          • Nurse from mammary glands
        • -Hair
          • Present as fetuses
    • General information
      • Unique characters
        • -Not even seen in other marine mammals (manatees, seals, sea lions and walruses)
        • Example:
        • 1.* Streamlined bodies that are thick and round
        • 2. Tales has horizontal flukes
        • 3. Dorsal fin is stiffened by connective tissue, but is fleshy and entirely without supporting bone
    • General information
      • Food source
        • Baleen whales (humpback, gray and blue whales)
        • -Krill (shrimp like)
        • -Phytoplankton
        • Toothed whales (killer whales, dolphins, sperm whales)
        • -fish
        • -squid
        • -other marine animals (seals, sea lions)
    • General information
      • Blowholes
        • Baleen whales
          • Two opening
        • Toothed whales
          • One opening
    • Father of whale evolution
      • John Ray (1693)
        • Based on whale similarity to terrestrial mammals, he recorded them as mammals
      • Darwin (1859)
        • Suggested that whales arose from bears
        • Embarrassed by criticism remove his drawing of swimming bears from the later editions of the Origin
    • Father of whale evolution
      • Flower (1883)
        • Recognized that whales have persistent rudimentary and vestigial features characteristic of terrestrial mammals
        • Confirming terrestrial to marine species
      • Van Valen (1966) and Szalay (1969)
        • Associated early whales with mesonychid condylarths (primitive carnivorous)
    • Evidence
      • Morphological
      • Tympanic bone
        • Right tympanic bone*
        • Its cross section in bottle-nosed dolphin (Tursiops truncatus)
      • m.e. –middle ear cavity
      • s.p. –sigmoid process
      • Inv -involucrum
    • Evidence
      • Dental morphology
      • - marker of evolution
      • -determine phylogeny, and they correlate well with diet
      • -reveal a series of evolutionary steps leading from the complex shape of the most ancient land mammals to simple one-prong morphology of modern odontocetes
      • -toward a reduction of crests and basins
      • -pronglike cusps are lined up in a single row
    • Evidence
      • Morphology (other)
        • Axis of foot symmetry
          • Falls between the 3 rd and 4 th digits, is rarely found in other groups
          • Still present of the pelvis and femur
    • Evidence
      • Molecular evidence
        • Whales are closely related to ungulates Order Artiodactyla (even-toed ungulates)
          • Examined myoglobin, lens alpha-crystallin A, cytochrome c
          • Protein, gene,
          • enzymes
    • Evidence
      • A. traditional hypothesis
      • of relationship with a monophyletic
      • Artiodactyla containing two major
      • clades and the extinct clade
      • Mesonychia is the sister taxon of
      • cetaceans, support by data
      • that fossilize
      • B. cladogram supported
      • by molecular data
    • Evidence
      • Geochemical evidence
        • Comparing the isotopic ratios
          • Oxygen
            • Freshwater: (high) light isotopic oxygen and (low) in heavy oxygen
            • Marine: (low) light isotopic oxygen and (high) in heavy oxygen
          • from enamel
            • The usefulness of enamel stems from its formation via
            • accretion over a limited interval during an animal’s life.
            • Once formed, enamel does not turn over and its stable-isotope composition remains fixed, providing a nearly continuous record that may cover a period of months to years and can be retained for millions of years after fossilization
    • Evidence
      • Marine should show very small different in heavy oxygen
        • - Graph-mean enamel heavy oxygen
        • -modern aquatic and terrestrial mammals
        • -black symbols –terrestrial
        • -open symbols –marine
        • -gray symbols –freshwater
    • Evidence
        • Campareing the isotopic
          • Carbon
            • -directly control by the carbon value of an animal’s diet
          • Before dietary reconstructions can be drawn from these analysis
            • Two factor must be consider
              • Magnitude off fractionation between diet and enamel must be know
              • Range in carbon values of dietary resources available to an animals must be gauged
    • Evidence*
    • Evidence*
    • Step of evolution
      • Sinonyx - wolf-sized mesonychid (a primitive ungulate)
      • characters linkages
        • elongated muzzle
        • enlarged jugular foramen
        • tooth count was the primitive mammalian number (44)
      • Pakicetus
        • oldest cetacean, and the first known archaeocete
      • Characters linkages
        • narrow braincase
        • a high, narrow sagittal crest, and prominent lambdoidal crests
    • Step of evolution
      • Ambulocetus
        • the walking whale that swims
      • Character
        • Amphibious, back legs are better adapted for swimming than walking on land
      • Rodhocetus
        • had a tail fluke
      • Character
        • must have been a very good tail-swimmer, and it is the earliest fossil whale committed to this manner of swimming.
      • Basilosaurus
        • next evolutionary grade in whale evolution
        • long, thin, serpentine animal
    •  
    • Step of evolution
    • Step of evolution
    • Conclusion
      • With so much evidences supporting the evolution of whales from terrestrial mammals
      • I conclude that this must be true
    • References
      • Lori Marino*, Richard C. Connor, R. Ewan Fordyce, Louis M. Herman, Patrick R. Ho,Louis Lefebvre, David Lusseau, Brenda McCowan, Esther A. Nimchinsky, Adam A. Pack, Luke Rendell, Joy S. Reidenberg, Diana Reiss, Mark D. Uhen, Estel Van der Gucht, Hal Whitehead “Cetaceans Have Complex Brains for Complex Cognition.” PLoS Biology , May 2007 | Volume 5 | Issue 5 | e139
      • JONATHAN H. GEISLER, “New Morphological Evidence for the Phylogeny of Artiodactyla, Cetacea, and Mesonychidae.” AMERICAN MUSEUM NOVITATES, Number 3344, 53 pp., 11 figures August 28, 2001
      • D. ANN PABST, “To Bend a Dolphin: Convergence of Force Transmission Designs in
      • Cetaceans and Scombrid Fishes.” AMER. ZOOL ., 40:146–155 (2000)
      • MAUREEN A. O’LEARY, “The Phylogenetic Position of Cetaceans: Further Combined Data Analyses, Comparisons with the Stratigraphic Record and a Discussion of
      • Character Optimization.” AMER. ZOOL ., 41:487–506 (2001)
      • J. G. M. THEWISSEN AND SUNIL BAJPAI, “Whale Origins as a Poster Child for Macroevolution.” BioScience • December 2001 / Vol. 51 No. 12
      • J. G. M. THEWISSEN AND S. BAJPAI, “DENTAL MORPHOLOGY OF REMINGTONOCETIDAE (CETACEA, MAMMALIA).” J. Paleont., 75(2), 2001, pp. 463–465
      • JESSICA M. THEODOR. MOLECULAR CLOCK DIVERGENCE ESTIMATES AND THE FOSSIL RECORD OF CETARTIODACTYLA.” J. Paleont ., 78(1), 2004, pp. 39–44
      • S. I. MADAR, “THE POSTCRANIAL SKELETON OF EARLY EOCENE
      • PAKICETID CETACEANS.” J. Paleont ., 81(1), 2007, pp. 176–200
      • S. I. MADAR1, J. G. M. THEWISSEN2, and S. T. HUSSAIN. “ADDITIONAL HOLOTYPE REMAINS OF AMBULOCETUS NATANS (CETACEA,
      • AMBULOCETIDAE), AND THEIR IMPLICATIONS FOR LOCOMOTION IN EARLY WHALES.” Journal of Vertebrate Paleontology 22(2):405–422, June 2002
      • MARK T. CLEMENTZ1, ANJALI GOSWAMI2, PHILIP D. GINGERICH3, and PAUL L. KOCH4, “ISOTOPIC RECORDS FROM EARLY WHALES AND SEA COWS: CONTRASTING PATTERNS OF ECOLOGICAL TRANSITION.” Journal of Vertebrate Paleontology 26(2):355–370, June 2006
      • Erich M. G. Fitzgerald, “A bizarre new toothed mysticete (Cetacea) from Australia and the early evolution of baleen whales.” Proc. R. Soc. B (2006) 273, 2955–2963