2. Non-vertebrate Chordates, Fishes, and Amphibians Chapter 30

3. Phylum Chordata lClContains three sub-phyla: –V–Vertebrata –U–Urochordata –C–Cephalochordata lAlAll chordates at some point in their life span must possess four characteristics:

4. 1) A hollow, dorsal nerve cord 2) A notochord (supporting rod) 3) Pharyngeal gill slits 4) A tail that extends beyond the anus

5. lAlAlso known as the tunicates or “sea squirts” lBlBasically a sack with two siphons.

6. l Examples: amphioxus and lancelets

7. Vertebrates  Most numerous chordates  Anterior, large brain  Jointed internal skeleton  Usually two pairs of appendages and some type of tail  Closed circulatory system  Gills or lungs and a chambered heart

8. 7 major classes of vertebrates l Jawless fishes, cartilaginous fishes, bony fishes, amphibians, reptiles, birds, mammals l Ectotherms = “cold-blooded” body temp changes with the environment. l Endotherms = “warm blooded” body tem remains fairly constant

9. FISH or FISHES lBlBoth words can be used for the plural of a fish. l“l“Fishes” is often used when talking about taxonomy or classification.

10. 1. Class Agnatha l “jawless fishes” l Most primitive vertebrates l No scales nor fins l Cartilage skeleton l No jaws l Both fresh and salt water varieties. l examples: lampreys and hagfish

11. LAMPREY l Both fresh and salt water. (parasitic) l Possess a tongue with teeth that gnaw a hole in its victim then sucks out the blood. l Can be harmful to fish populations.

12. HAGFISH lOlOnly found in salt water. scavengers lAlAlso known as “slime eels” lPlProduce great amounts of slime for defense. Can tie themselves in a knot

13. 2. Class Chondricthyes l Chondros (Gr. Cartilage) l Ichthys (Gr. Fish) l Mostly marine l 2 chambered heart l Movable upper and lower jaws l ex. Sharks, skates, and rays

14. Skates and rays l Flattened body (countershading) l Eat worms, mollusks, and other invertebrates l Can be specialized for defense –Stingers –Electric rays

15. SHARKS Internal fertilization. Viviparous = live birth Need to be constantly swimming to keep water moving over the gills Very highly developed sense of smell. Covered with sandpaper-like scales called placoid scales.

16. Medicinal uses lClCurrently shark cartilage is being tested as a possible cure for cancer.

17. 3. Class Osteicthyes O steo- Gr. Meaning “bone” K nown as the bony fishes L argest class of vertebrates. V ary in size, shape, and structure. C omplex nervous system (lateral lines) V ery specialized. E lectric eel, pufferfish, angler fish, butterfly fish

18. Wide Variety

19. Structure of a bony fish l Usually four pairs of gills covered by a bony flap (operculum) l 2 chambered heart l Many have scales and fins l Swim bladder = gas-filled sac which is used for buoyancy (maintain depth)

20. Reproduction l External. l A female will lay upto 500,000 eggs. l The male usually swims over the eggs depositing milt (sperm containing fluid)

21. The Coelacanth l A special fleshy-lobed finned fish thought to be extinct. l 1938 one was caught off the southern coast of Africa.

22. 4. Class Amphibia l “from water to land” l Reproduction and development must take place in or near water. l Thin moist skin l Two pairs of limbs, one pair of nostrils l 3 chambered heart l Young show a distinct larval form.

23. Examples:

24. Frog anatomy and function lLlLarge powerful hind legs for jumping. l2l2 large movable eyes lTlTympanic membrane l3l3 eyelids –U–Upper –L–Lower –N–Nictitating membrane (transparent; used for underwater sight.

25. digestion l Large mouth. l Long sticky spade-shaped tongue l Teeth along upper jaw. l A pair of vomerine teeth used to hold prey in mouth l Esophagus...stomach...small intestine(site of absorption)..large intestine...cloaca…anal opening.

26. Circulatory system l Oxygenated blood enters left atrium from lungs. Deoxygenated blood enters right atrium from rest of body. l Both empty into ventricle where a mixture of oxygen and non-oxygen blood is pumped out

27. Respiratory system l Tadpoles use gills to breathe. l Adult frog uses three structures for respiration.

28. Nervous system l Possess both a cranial and peripheral nervous system l Multi-lobed brain l Olfactory(smell) l Optic(sight) l Cerebrum(voluntary muscles) l Cerebellum(coordination) l Medulla(involuntary muscle action)

29. Excretory system l CO 2 excreted through the skin, other wastes filtered through the kidneys. l Urine is stored in urinary bladder then passed into cloaca and out of the body.

30. Reproduction l External fertilization l amplexus = male grasps female, eggs are released then quickly fertilized by the male.

31. Order Urodela l Salamanders and newts l Long bodies and tails l Live in dark, moist places.

32. Orders Anura & Apoda l ANURA l Frogs and toads l APODA l Caecilians l Legless amphibians

33. Assignment l Pages 793-794 –1-10, 14, 17, 18, 20, 23, 24, 28 l Page 795 1-10