Unit 26 Amniotes


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Unit 26 Amniotes

  1. 1. KEY CONCEPT Reptiles, birds, and mammals are amniotes.
  2. 2. <ul><li>Amniote embryos develop in a fluid-filled sac. </li></ul><ul><li>The amniotic sac contains everything an embryo needs to grow. </li></ul><ul><ul><li>some develop inside mother’s body </li></ul></ul><ul><ul><li>some develop inside a tough, semipermeable shell </li></ul></ul>
  3. 3. <ul><li>The amniotic egg allowed vertebrates to reproduce on land. </li></ul>Embryo Allantois Holds waste materials as the embryo grows Yolk sac Contains the nutrient supply for the growing embryo Amnion Protects and surrounds the embryo Chorion Allows gas exchange with outside environment
  4. 4. <ul><li>Anatomy and circulation differ among amniotes. </li></ul><ul><li>Other amniotes, including dinosaurs, evolved a more upright stance. </li></ul><ul><li>The first animals walked in a sprawl. </li></ul>
  5. 5. <ul><li>All amniotes have two circuits of blood vessels. </li></ul><ul><ul><li>pulmonary circuit moves blood from the heart to the lungs </li></ul></ul><ul><ul><li>systemic circuit moves blood from the heart to the rest of the body </li></ul></ul>
  6. 6. <ul><li>Amniotes have a three- or four-chambered heart. </li></ul><ul><ul><li>reptiles hearts have three chambers </li></ul></ul><ul><ul><li>birds and mammals hearts have four chambers </li></ul></ul>THREE-CHAMBERED HEART FOUR-CHAMBERED HEART
  7. 7. <ul><li>Amniotes can be ectothermic or endothermic. </li></ul><ul><li>Amniotes manage body heat in different ways. </li></ul><ul><ul><li>Ectotherms have body temperatures determined by the surrounding environment. </li></ul></ul><ul><ul><li>Endotherms use metabolic heat to keep tissues warm. </li></ul></ul><ul><li>Endotherms can live in a wider range of climates than ectotherms. </li></ul>
  8. 8. KEY CONCEPT Reptiles were the first amniotes.
  9. 9. <ul><li>Reptiles are a diverse group of amniotes. </li></ul><ul><li>Reptiles share several characteristics. </li></ul><ul><ul><li>ectotherms </li></ul></ul><ul><ul><li>covered with dry scales </li></ul></ul><ul><ul><li>reproduce by laying or retaining amniotic eggs </li></ul></ul><ul><ul><li>three-chambered heart </li></ul></ul><ul><ul><li>cloaca </li></ul></ul>
  10. 10. <ul><li>Reptiles have two reproductive strategies. </li></ul><ul><ul><li>Oviparous reptiles deposit eggs into an external nest. </li></ul></ul><ul><ul><li>Viviparous reptiles retain eggs and give birth to live offspring. </li></ul></ul>
  11. 11. <ul><li>Reptiles have been evolving for millions of years. </li></ul><ul><li>Over time, amniotes evolved into three different groups. </li></ul><ul><ul><li>synapsids </li></ul></ul><ul><ul><li>anapsids </li></ul></ul><ul><ul><li>diapsids </li></ul></ul>
  12. 12. <ul><li>The diversity of ancient reptiles led to the evolution of modern reptiles, birds, and mammals. </li></ul>
  13. 13. <ul><li>There are four modern groups of reptiles. </li></ul><ul><li>Turtles, tortoises, and terrapins are the remaining anapsids. </li></ul><ul><ul><li>bony shell encases body </li></ul></ul><ul><ul><li>200 species </li></ul></ul>
  14. 14. <ul><li>Sphenodonts are closely related to lizards. </li></ul><ul><ul><li>diapsids </li></ul></ul><ul><ul><li>primitive characteristics </li></ul></ul><ul><ul><li>two species </li></ul></ul>
  15. 15. <ul><li>Snakes and lizards are very closely related and share a number of features. </li></ul><ul><ul><li>diapsids </li></ul></ul><ul><ul><li>shed skin at regular intervals </li></ul></ul><ul><ul><li>flexible skull </li></ul></ul><ul><ul><li>Jacobson’s organ </li></ul></ul>brain tongue Jacobson’s organ
  16. 16. <ul><li>Crocodilians are more closely related to birds than other diapsids. </li></ul><ul><ul><li>diapsids </li></ul></ul><ul><ul><li>semi-aquatic predators </li></ul></ul><ul><ul><li>23 species </li></ul></ul>
  17. 17. KEY CONCEPT Birds have many adaptations for flight.
  18. 18. <ul><li>Birds evolved from theropod dinosaurs. </li></ul><ul><li>Birds and many theropods share anatomical features. </li></ul><ul><ul><li>hollow bones </li></ul></ul><ul><ul><li>fused collarbones that form V-shaped wishbone </li></ul></ul><ul><ul><li>rearranged muscles in the hips and legs </li></ul></ul><ul><ul><li>“ hands” that have lost their fourth and fifth fingers </li></ul></ul><ul><ul><li>feathers </li></ul></ul>
  19. 19. <ul><li>The oldest undisputed fossilized bird is Archaeopteryx . </li></ul>
  20. 20. <ul><li>A bird’s body is specialized for flight. </li></ul><ul><li>Birds have several unique features that allow them to fly. </li></ul><ul><ul><li>wings to produce flight </li></ul></ul><ul><ul><li>strong flight muscles to move the wings </li></ul></ul><ul><ul><li>active metabolism that provides energy to the muscles </li></ul></ul><ul><ul><li>hollow bone structure to minimize weight </li></ul></ul><ul><ul><li>gonads active during only part of year </li></ul></ul>small intestine large intestine lung gizzard kidney cloaca crop sternum (keel) heart liver pectoral muscle
  21. 21. <ul><li>Wings are structures that enable birds to fly. </li></ul><ul><ul><li>airfoil shape </li></ul></ul><ul><ul><li>covered with feathers </li></ul></ul>
  22. 22. <ul><li>Air sacs help a bird meet its oxygen demand during flight. </li></ul>
  23. 23. <ul><li>Birds have spread to many ecological niches. </li></ul><ul><li>The shape of a bird’s wing reflects the way it flies. </li></ul><ul><ul><li>short and broad </li></ul></ul><ul><ul><li>long and narrow </li></ul></ul>
  24. 24. <ul><ul><li>wide and broad </li></ul></ul><ul><li>The shape of a bird’s wing reflects the way it flies. </li></ul><ul><ul><li>stout and tapered </li></ul></ul>small intestine large intestine lung gizzard kidney cloaca crop sternum (keel) heart liver pectoral muscle
  25. 25. <ul><li>Differences in the shape of a bird’s beak reflects how it eats. </li></ul><ul><ul><li>spearlike </li></ul></ul><ul><ul><li>hooked </li></ul></ul><ul><ul><li>chisel-shaped </li></ul></ul>blue-footed booby green woodpecker Bald eagle
  26. 26. <ul><li>Birds show great diversity in their foot shape. </li></ul><ul><ul><li>webbed </li></ul></ul><ul><ul><li>heavy claws </li></ul></ul><ul><ul><li>different toe location </li></ul></ul>blue-footed booby bald eagle green woodpecker
  27. 27. KEY CONCEPT Evolutionary adaptations allowed mammals to succeed dinosaurs as a dominant terrestrial vertebrate.
  28. 28. <ul><li>All mammals share several common characteristics. </li></ul><ul><li>Mammals are active, large-brained, endotherms with complex social, feeding, and reproductive behaviors. </li></ul>
  29. 29. <ul><li>All mammals share four anatomical characteristics. </li></ul><ul><ul><li>hair to retain heat </li></ul></ul><ul><ul><li>mammary glands to produce milk </li></ul></ul>
  30. 30. <ul><ul><li>a middle ear with three bones to hear higher-pitched sounds </li></ul></ul><ul><ul><li>chewing jaw to break up food quicker </li></ul></ul><ul><li>All mammals share four anatomical characteristics. </li></ul>
  31. 31. <ul><li>A set of adaptations in the mammalian jaw makes chewing possible. </li></ul><ul><ul><li>secondary palate closes off air passages </li></ul></ul><ul><ul><li>muscles move jaw side-to-side </li></ul></ul>
  32. 32. <ul><li>Modern mammals are divided into three main groups. </li></ul><ul><li>Monotremes lay eggs. </li></ul><ul><ul><li>duck-billed platypus </li></ul></ul><ul><ul><li>echidna </li></ul></ul>
  33. 33. <ul><li>Marsupials give birth to live young that grow to maturity inside a pouch. </li></ul><ul><ul><li>opossum </li></ul></ul><ul><ul><li>kangaroo </li></ul></ul><ul><ul><li>wombat </li></ul></ul><ul><ul><li>koala </li></ul></ul>
  34. 34. <ul><li>Eutherians give birth to live young that have completed fetal development. </li></ul><ul><ul><li>most familiar mammals </li></ul></ul><ul><ul><li>humans </li></ul></ul><ul><li>Eutherians filled many niches after the extinction of the dinosaurs. </li></ul>