From Fins to Fists

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  2. Class Sarcopterygii
    • The lobe-fins have muscular pelvic and pectoral fins
    • Three lineages survive and include coelacanths, lungfishes, and tetrapods
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    tetrapod origin
  4. changes made in class Sarcopterygii
    • Old lineages
    • Transitional fossils
    • Fins shifting to legs
    • Gills to lungs
    • Coelacanth fossils found in more than 350 MYA
  5. Tetrapods (4 feet)
    • Derived Characters of Tetrapods
    • –Tetrapods have some specific adaptations:
    • Four limbs, and feet with digits
    • Ears for detecting airborne sounds
    • In one lineage of lobe-fins, the fins became progressively more limb-like while the rest of the body retained adaptations for aquatic life
  6. Amphibia
    • Amphibians are represented by about 6,150 species of organisms in three orders
    • Amphibian means “both ways of life,” referring to the metamorphosis of an aquatic larva into a terrestrial adult
    • Most amphibians have moist skin that complements the lungs in gas exchange
    • Fertilization is external in most species, and the eggs require a moist environment
  7. Amphibian Orders
    • Order Urodela includes salamanders, which have tails
    • Order Anura includes frogs and toads, which lack tails
    • Order Apoda includes caecilians, which are legless and resemble worms
  8. Reasons for amphibian decline around the world
    • Chrytid fungus
    • Habitat loss
    • Climate change
    • Trematodes (cause deformities)
    • Pollution and chemicals
  9. Amniotes
    • Amniotes are a group of tetrapods whose living members are the reptiles, including birds, and mammals
    • Derived Characters:
    • –amniotic egg, which contains membranes that protect the embryo–relatively impermeable skin
    • –ability to use the rib cage to ventilate the lungs
    • The extra-embryonic membranes are the amnion, chorion, yolk sac, and allantois
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    amniotic egg
  11. Reptilia
    • The reptile clade includes the tuataras, lizards, snakes, turtles, crocodilians, birds, and the extinct dinosaurs
    • Derived Characters:
    • –Reptiles have scales that create a waterproof barrier
    • –They lay shelled eggs on land
    • Most reptiles are ectothermic
    • Birds are endothermic
  12. ectothermic
    absorbing external heat as the main source of body heat
  13. endothermic
    capable of keeping the body warm through metabolism
  14. Lepidosaurs
    The lepidosaurs include tuataras, lizards, and snakes
  15. archosaurs
    lineage produced the crocodilians, pterosaurs, and dinosaurs
  16. Turtles
    • All turtles have a boxlike shell made of upper and lower shields that are fused to the vertebrae, clavicles, and ribs
    • Some turtles have adapted to deserts and others live entirely in oceans or ponds and rivers
  17. crocadilians
    (alligators and crocodiles) belong to an archosaur lineage that dates back to the late Triassic
  18. birds
    Birds are archosaurs, but almost every feature of their reptilian anatomy has undergone modification in their adaptation to flight
  19. bird characteristics
    • The major adaptation is wings with keratin feathers
    • Lack of a urinary bladder
    • Females with only one ovary
    • Small gonads
    • Loss of teeth
  20. Class mammalia
    • Mammals are represented by more than 5,300 species
    • By the early Cretaceous, the three living lineages of mammals emerged: monotremes, marsupials, and eutherians
    • Mammals did not undergo a significant adaptive radiation until after the Cretaceous
  21. Derived characters of Mammalia
    • Mammary glands, which produce milk
    • Hair
    • A larger brain than other vertebrates of equivalent size
    • Differentiated teeth
  22. Monotremes
    are a small group of egg-laying mammals consisting of echidnas and the platypus
  23. Marsupials
    • include opossums, kangaroos, and koalas
    • –The embryo develops within a placenta in the mother’s uterus
    • –A marsupial is born very early in its development
    • –It completes its embryonic development while nursing in a maternal pouch called a marsupium
  24. Eutherians
    • Compared with marsupials, eutherians have a longer period of pregnancy
    • Young eutherians complete their embryonic development within a uterus, joined to the mother by the placenta
    • Molecular and morphological data give conflicting dates on the diversification of eutherians
  25. Primates
    • The mammalian order Primates includes lemurs, tarsiers, monkeys, and apes
    • are members of the ape group
    • Most primates have hands and feet adapted for grasping
  26. Hominids
    • The study of human origins is known as paleoanthropology
    • Hominids are more closely related to humans than to chimpanzees
    • Paleoanthropologists have discovered fossils of about 20 species of extinct hominids
    • Hominids originated in Africa about 6–7 million years ago
    • Early hominids had a small brain but probably walked upright
  27. humans
    A number of characters distinguish humans from other apes:
    • –Upright posture and bipedal locomotion
    • –Larger brains
    • –Language capabilities and symbolic thought
    • –The manufacture and use ofcomplex tools
    • –Shortened
    • –Shorter digestive tract
Card Set
From Fins to Fists
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