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Unit 9 Chordates

Unit 9 Chordates. Ch. 30 Nonvertebrate Chordates, Fishes, & Amphibians. What Is a Chordate?. A chordate is an animal that has, for at least some stage of its life, a dorsal, hollow nerve cord; a notochord; pharyngeal pouches; & a tail that extends beyond the anus. What Is a Chordate?.

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Unit 9 Chordates

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  1. Unit 9 Chordates Ch. 30 Nonvertebrate Chordates, Fishes, & Amphibians

  2. What Is a Chordate? • A chordate is an animal that has, for at least some stage of its life, a dorsal, hollow nerve cord; a notochord; pharyngeal pouches; & a tail that extends beyond the anus

  3. What Is a Chordate? • Notochord - a long supporting rod that runs through the body just below the nerve cord • Pharyngeal pouches - paired structures in the throat region, used to help in gas exchange

  4. Most Chordates Are Vertebrates • Vertebrae - individual segments that make up the backbone

  5. Nonvertebrate Chordates • The 2 groups of nonvertebrate chordates are tunicates & lancelets • Both are soft-bodied marine organisms • Tunicates are often called sea squirts because of the stream of water they eject

  6. Nonvertebrate Chordates • Lancelets are small nonvertebrate chordates that often live with their bodies 1/2 buried in sand

  7. What Is a Fish? • Fishes are aquatic vertebrates; most fishes have paired fins, scales, & gills

  8. Evolution of Fishes • The evolution of jaws & the evolution of paired fins were important developments during the rise of fishes

  9. Form & Function in Fishes • Adaptations to aquatic life include various modes of feeding, specialized structures for gas exchange, & paired fins for locomotion

  10. Groups of Fishes • When you consider their basic internal structure, all living fishes can be classified into 3 groups: jawless fishes, cartilaginous fishes, & bony fishes

  11. Diversity of Ray-Finned Fishes

  12. Ecology of Fishes • Fishes are important source of food for many organisms

  13. What Is an Amphibian? • An amphibian is a vertebrate that, typically, lives in water as a larva & on land as an adult, breathes with lungs as an adult, has moist skin that contains mucous glands, & lacks scales & claws

  14. Evolution of Amphibians • Early amphibians evolved several adaptations that helped them live at least part of their lives out of water • Bones in the limbs of amphibians became stronger, permitting more efficient movement

  15. Evolution of Amphibians • Lungs & breathing tubes enabled them to breathe air • The sternum, or breastbone, formed a bony shield to support & protect internal organs, especially the lungs

  16. Form & Function in Amphibians • Tadpoles are filter feeders, adult amphibians are almost entirely carnivorous

  17. Form & Function in Amphibians • An amphibian’s heart has 3 chambers, 2 atria & 1 ventricle • Some wastes diffuse across the skin, but kidneys remove most wastes from bloodstream

  18. Form & Function in Amphibians • An amphibian typically begins its life in water, then moves on land as an adult

  19. Groups of Amphibians • The 3 groups of amphibians alive today are salamanders, frogs & toads, & caecilians

  20. Diversity of Amphibians

  21. Ecology of Amphibians • Some amphibians that release toxins have brightly colored bodies • The colors & patterns serve as a warning to potential predators

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