1 / 26

The Chordates

The Chordates. Chapters 30-32 Biology – Miller • Levine. Chordates. Phylum Chordata Includes two invertebrate subphyla: lancelets and tunicates Subphylum Vertebrata. Chordate Characteristics. Dorsal, hollow nerve cord – the brain and spinal cord

jesse-bush
Télécharger la présentation

The Chordates

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Chordates Chapters 30-32 Biology – Miller • Levine

  2. Chordates • Phylum Chordata • Includes two invertebrate subphyla: lancelets and tunicates • Subphylum Vertebrata

  3. Chordate Characteristics • Dorsal, hollow nerve cord – the brain and spinal cord • Notochord – flexible, longitudinal rod located between the digestive tract and the nerve cord • Pharyngeal pouches – gill structures in the pharynx • Post-anal tail – tail to the rear of the anus

  4. Chordate Characteristics • The characteristics are not always visible in the adult form, but are always present in the embryo

  5. Vertebrates • Subphylum that includes mammals, birds, reptiles, amphibians and the various classes of fishes • Unique features include cranium and backbone

  6. Fishes

  7. Agnathans • Jawless fish • Class Myxini (hagfishes) • Class Cephalaspidomorphi (lampreys)

  8. Class Chondrichthyes • Cartilaginous fishes • Include sharks and rays • Have a flexible skeleton made of cartilage • Lateral line system – row of sensory organs running along each side of the body, detects minor vibrations

  9. Class Chondrichthyes

  10. Class Osteichthyes • Bony fishes (trout and goldfish) • Also have a lateral line system • Operculum – protective flap that covers the gills • Swim bladder – gas-filled sac that keeps them buoyant

  11. Class Osteichthyes • Most are ray-finned fishes – fins supported by thin, flexible rays • Lungfishes – must surface to gulp air into their lungs • Lobe-finned fishes – fins are supported by stout bones

  12. Amphibians

  13. Class Amphibia • Frogs and salamanders • Exhibit a mixture of aquatic & terrestrial adaptations • Need water to reproduce • Depend on their moist skin to supplement lung function in exchanging gases

  14. Class Amphibia • First vertebrates to colonize land • Tetrapods (“four legs”) – terrestrial vertebrates (amphibians, reptiles, birds & mammals)

  15. Reptiles

  16. Class Reptilia • Snakes, lizards, turtles, crocodiles, and alligators • Have many additional adaptations for living on land • Water-proofed scales to prevent dehydration • Amniotic egg – water-containing egg enclosed in a shell

  17. Class Reptilia • Ectotherms – warms itself by absorbing external heat • Can survive on less than 10% of the calories required by mammals • Mesozoic era – “age of reptiles” – the time of the dinosaurs

  18. Birds

  19. Class Aves • Birds • Reptilian features – scales on legs, amniotic egg • Almost all species are able to fly

  20. Class Aves • Adaptations for flight: • Light, hollow bone • Absence of some internal organs • Are toothless • Endotherms – maintain temperature using metabolic heat • Wings – strong muscles, feathers

  21. Mammals

  22. Class Mammalia • Probably evolved from reptiles • Most are terrestrial, some are aquatic (dolphins, whales), some can fly (bats) • Two unique features: hair and mammary glands • Are endotherms • Have a fluid filled amniotic sac

  23. Three Major Groups • Monotremes – egg-laying mammals (platypus) • Marsupials – pouched mammals (kangaroo) • Eutherians – placental mammals • Make up almost 95% of mammals • Marsupials and Eutherians both have a placenta which joins the embryo to the mother and provides nutrients to the embryo

  24. Class Mammalia

  25. Primates • Order that includes monkeys, apes & humans • Early primates were small, arboreal (tree-dwelling) mammals • Limber shoulder joints, dexterous hands, eyes close together on face, excellent hand-eye coordination

  26. Primates • Divided into two main groups: • Prosimians (lemurs) • Anthropoids (monkeys, apes & humans) • Humans are most closely related to apes

More Related