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Nonvertebrate Chordates, Fishes, and Amphibians

Nonvertebrate Chordates, Fishes, and Amphibians. Ms. Moore 3-1-13. What is a Chordate?. Phylum: Chordata A chordate is an animals that has, for at least some stage of life, a dorsal, hollow nerve cord; a notochord ; pharyngeal pouches ; and a tail that extends beyond the anus.

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Nonvertebrate Chordates, Fishes, and Amphibians

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  1. Nonvertebrate Chordates, Fishes, and Amphibians Ms. Moore 3-1-13

  2. What is a Chordate? • Phylum: Chordata • A chordate is an animals that has, for at least some stage of life, a dorsal, hollow nerve cord; a notochord; pharyngeal pouches; and a tail that extends beyond the anus. • Hollow nerve cord: nerves branch off and connect to organs • Notochord: long supporting rod that runs through the body just below the nerve cord • Pharyngeal pouches: paired structures in the throat region; can develop slits  gills in some chordates • Tail: can contain bone and muscle; can be used for motility

  3. Characteristics of Chordata

  4. Most Chordates are Vertebrates • Figure 30-2 • 96% of all chordates are placed in the subphylum: Vertebrata vertebrates • Vertebrae: backbone replaces the notochord in most developing vertebrates; encloses and protects the spinal cord • Part of endoskeleton • Grows as the animal grows • Made up of living and non living cells

  5. Nonvertebrate Chordates • 2 groups of Chordata do not have a backbone • Soft bodied marine animals • 550 mya = ancestors! • Tunicates • Subphylum: Urochordata • Filter feeders • Open Circulatory • Lancelets • Subphylum: Cephalochordata • Small fishlike creatures • Live on sandy ocean body • Closed Circulatory • Diffusion through skin

  6. Mini Lab • Draw a picture depicting a typical: • Tunicate (p 769) • Lancelet (p 770) • Label all parts

  7. What is a Fish? • Fishes are aquatic vertebrates, most fishes have paired fins, scales, and gills. • Fins = movement • Scales = protection • Gills = exchanging gases

  8. Evolution of Fishes • The evolution of jaws and paired fins were important developments during the rise of fishes. • First Fishes: 510 mya • Jawless with armored plates • The Age of Fishes: 505-410 mya • Ancestors of hagfishes and lampreys • Arrival of Jaws and Paired Fins • Filter feeders  herbivores and carnivores • Fins attached by cartilage  movement • Cartilage: strong tissue that supports the body; softer and more flexible than bone • Modern Fishes • Ancestors of sharks and rays: cartilage • Bony fishes: bone

  9. Form and Function in Fishes • Feeding • Herbivores, carnivores, parasites, filter feeders, and detrius feeders • Mouth  Esophagus  Stomach  other organs  Intestines  Anus

  10. Respiration • Gills: located on either side of the pharynx; made up of feathery filaments • Lungs: specialized organs to help in shallow waters • Circulation • Closed circulatory system: single loop • Heart  gills  body  heart • Atrium: large muscular chamber located in the heart • Ventricle: thick-walled, muscular chamber; pumping portion of the heart

  11. Response • Fishes have well-developed nervous systems organized around a brain • Cerebrum: voluntary activities; senses • Cerebellum: coordination • Medulla oblongata: fx of organs • Lateral line system: sense vibration/movement • Movement • S-shaped movement—muscles in the back • Fins increase surface area = faster • Swim bladder: gas filled organ that adjusts buoyancy

  12. Reproduction • Eggs can be fertilized externally or internally • Oviparous: eggs hatch outside the mother’s body; salmon • Ovoviviparous: eggs stay in the mother’s body after internal fertilization; guppy • Viviparous: embryos stay in the mother’s body after internal fertilization; some sharks

  13. Groups of Fishes • Jawless Fishes • Class: Agnatha • No true teeth or jaws • Skeletons made of fibers and cartilage (keep notochords) • Include: • lampreys—filter feeders as larvae/parasites as adults • Hagfishes—detrius feeders; slime; 6 hearts; open; knots! • Sharks and Relatives • Class: Chondrichthyes (a.k.a. cartilage) • Include: sharks, rays, skates, and others • Bony Fish • Class: Osteichthyes • Skeleton made of bone • Almost all include ray-finned fishes

  14. Ecology of Fishes • Aquatic Life • Freshwater = low salt concentration • Ocean = high salt concentration • Movement/Migration • Anadromous fishes: ocean dwellers migrate to freshwater to breed • Lampreys • Salmon • Catadromous fishes: freshwater fishes migrate to ocean to breed • European eels

  15. Mini Lab • Draw the diagram of the fish, label all parts (p774) • Draw the diagram of a fish brain, label all parts (p777) • Fill out long study guide Agnatha Osteichthyes • Complete handout

  16. What is an Amphibian? • An amphibian is a vertebrate that, with some exceptions, lives in water as a larva and on land as an adult, breathes with lungs as an adult, has moist skin that contains mucous glands, and lacks scales and claws. • Evoultion of Amphibians: • Bones became stronger = movement on land • Lungs = breath air • Sternum = protection of organs

  17. Form and Function in Amphibians • Feeding • Tadpoles: filter feeders or herbivores (algae) with long intestines • Adult: meat-eating with shorter intestines • Sticky tongues to catch prey • Mouth  esophagus  stomach  intestine  liver/pancreas/gallbladder  colon  cloaca (digestive wastes, urine, eggs/sperm leave body) • Respiration • Larval: gas exchange through skin/gills • Adult: lungs some skin/mouth cavity (always exceptions—lung less salamanders)

  18. Circulation • Double loop system: first carries O2 rich blood from heart to lungs and skin and back; second carries O2 rich blood from heart to rest of body and back • 3 chambers: left atrium, right atrium, and ventricle • Excretion • Kidneys  ureters  bladder/cloaca • Reproduction • Frog eggs laid in water to undergo external fertilization • Eggs hatch into tadpoles • Tadpoles gradually grow limbs, lose tails/gills, and become carnivorous • Young adults move onto land

  19. Movement • Larva: move like fishes • Adult: use front and back legs to move in a variety of ways • Response • Brain much like a fish • Well developed nervous and sensory systems • Nictitating membrane: protects eye from underwater damage/keeps moist • Tympanic membrane: eardrums on each side of the head

  20. Groups of Amphibians • Salamanders (and Newts) • Order: Urodela • Long bodies and tails; most have 4 legs • Larva and adults are carnivorous • Moist environment or underwater • Frogs and Toads • Order: Anura • Jump! Frogs = long legs, near water; Toads = shorter legs; moist woods, even deserts • Caecillians • Order: Apoda • Legless, carnivorous, live in water or burrow in moist soil, many have fishlike scales in skin

  21. Ecology of Amphibians • Must live near water • Some exceptions: desert amphibians have special adaptations • Protection from predators • Skin colorings/markings • Poison glands in skin • Global decline • Amphibians are very susceptible to the environment

  22. Mini Lab Draw the following in your lab manual: • Figure 30-23 (p784) • Notice the location of the organs • Figure 30-24 (p785) • Use different colors to demonstrate the direction of blood throughout the amphibian • Create a life cycle for an amphibian • Can use figure on p786

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