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Chordates

Chordates. Characteristics common to ALL chordates. Dorsal nerve cord Pharyngeal slits Notochord Tail. Dorsal nerve cord. Pharyngeal Slits. The wall of the pharynx is perforated by up to 200 vertical slits , which are separated by stiffening rods. Jawless to Jaw.

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Chordates

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  1. Chordates

  2. Characteristics common to ALL chordates • Dorsal nerve cord • Pharyngeal slits • Notochord • Tail

  3. Dorsal nerve cord

  4. Pharyngeal Slits • The wall of the pharynx is perforated by up to 200 vertical slits, which are separated by stiffening rods.

  5. Jawless to Jaw

  6. Used to collect food in an aquatic environment

  7. Notochord • a flexible, rod-shaped body found in embryos of all chordates

  8. In lower vertebrates, it persists throughout life as the main axial support of the body, while in higher vertebrates it is replaced by the vertebral column.

  9. Tail

  10. Some animals lose tail during development

  11. Nonvertebrate chordates and Vertebrates • Nonvertebrate chordates have a notochord (analogous to spinal chord) but lack a bony covering- the vertebrae • Vertebrates have a spinal chord protected by bones

  12. Principle Chordate Features

  13. The Nonvertebrate Chordates • Tunicates (sea squirts) • exhibit neither a major body cavity nor visible segmentation • tadpole larva clearly exhibits all basic characteristics of a chordate • adults exist as sessile filter-feeders

  14. Tunicates

  15. The Nonvertebrate Chordates • Lancelets • scaleless, fishlike marine chordates • notochord runs entire length of dorsal nerve cord • feed on microscopic plankton using cilia-generated current

  16. Characteristics of Vertebrates • Vertebral column • Endoskeleton • Distinct, well-differentiated head with cranium • Closed circulatory system with chambered heart • RBC’s with hemoglobin

  17. Overview of the Evolution of Vertebrates • Main CLASSES • Fishes – cartilaginous and bony • Amphibia - amphibians • Reptilia - reptiles • Aves - birds • Mammalia - mammals

  18. Fishes • Over half of all vertebrates are fishes. • Characteristics (generally) • jaws and paired appendages (except lampreys and hagfish) • scales • fins • gills • single-loop blood circulation • Heart with 2 chambers (1 atrium, 1 ventricle) • Lateral line system

  19. History of the Fishes • Rise of active swimmers • Sharks and bony fishes replaced primitive fishes due to a superior swimming design. • caudal (tail) fin • dorsal (stabilizing) fins • pectoral (shoulder - elevator) fins • pelvic (hip- elevator) fins

  20. Hagfish

  21. Lamprey

  22. History of the Fishes • Sharks become top predators • Jaws with multiple rows of teeth • Paired pectoral and pelvic fins • Buoyancy from storing oil • extremely advanced reproduction • shark eggs fertilized internally • Most give birth to live young

  23. Hammerhead Shark

  24. Elephant Fish

  25. Whale Shark

  26. Tooth from Megalodon (left), and Great White

  27. History of the Fishes • Bony fishes dominate the water • Skeleton composed of bone • Swim bladder for bouyancy • Gills protected by operculum • highly mobile fins, thin scales, and completely symmetrical tails • Most have external fertilization and external development

  28. Angler Fish

  29. Deep Sea Angler Fish

  30. Flounder

  31. Electric Eel

  32. Sea horse and Sea dragon

  33. Another Sea dragon

  34. Mola mola or Ocean sunfish

  35. Coelacanth

  36. Coelacanth fossils

  37. Living Coelacanth

  38. Shark Dissection Following is a series of video clips of dissection of various shark species. This will give you some idea of what you will encounter with our shark lab

  39. Lobe-Finned Fish and Primitive Amphibians

  40. Amphibians • Live on both land and in water (“double life”) • Characteristics • legs • cutaneous respiration, lungs, gills • Heart with 3 chambers (double loop circulation) • Pulmonary • Systemic • External fertilization and development in nearly all

  41. History of the Amphibians • Adaptations for the invasion of land • legs to support body’s weight • lung to extract oxygen from the air • redesigned heart to drive new respiratory system • reproduction in water to prevent egg desiccation • system to prevent body desiccation

  42. History of the Amphibians • Amphibians today • Anura - amphibians without tails • most live in or near water, and return to water to reproduce • eggs fertilized externally and hatch into tadpoles • metamorphosis

  43. Poison dart frogs

  44. Proboscis frog

  45. African goliath frog

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