Lab 8: Echinoderms and Chordates

1. Lab 8: Echinoderms and Chordates

2. Task 1: Phylum Echinodermata • coelomate; unsegmented • pentamerous radial symmetry • water vascular system • dermal endoskeleton with spines

3. Task 1: Phylum Echinodermata • 4 selected classes to discuss: • Asteroidea (sea stars or starfish) • Ophiuroidea (brittle stars) • Echinoidea (sea urchins and sand dollars) • Holothuroidea (sea cucumbers)

4. Task 1: Phylum Echinodermata • or each: compare to Fig. 8-1, note body plan 5-part radial symmetry, endoskeleton, lack of segmentation • Asteroidea (sea stars) – five arms, madreporite, central disc, mouth, tube feet, coelom • Ophiuroidea (brittle stars) – five arms, central disc • Echinoidea (sea urchins and sand dollars) – look for pentamerous characteristics; jaws • more…..

5. Task 1: Phylum Echinodermata • examine the preserved specimens, note the following: • Holothuroidea (sea cucumbers) – not typically sedentary, just slow (lab manual is wrong) • tentacles at mouth; cloaca and vent at anus • radial muscles • alimentary canal (intestines) - thick • gonad – thinner, orange • respiratory trees – very thin, highly branched

6. Tasks 3 and 4: Chordates • group unified by four traits present at some point in the life cycle for all members • dorsal tubular (hollow) nerve cord • notochord • pharyngeal gill slits • postanal tail

7. Tasks 3 and 4: Chordates • three subphyla • Urochordata – tunicate or sea squirt • Cephalochordata – lancelet or amphioxus • Vertebrata – have a backbone; fish, amphibians, reptiles, birds, and mammals (classes listed later) • watch the video for some information on the body plan and development….

8. Task 4: Vertebrate Chordates • Vertebrata – 7 classes • Agnatha – jawless fish • Chondrichthyes – cartilaginous fish (sharks, skates, and rays) • Osteichthyes – bony fish with paired fins • Amphibia – two pairs of legs; smooth skin (frogs, salamanders, etc.) • Reptilia – two pairs of legs; scaly skin (lizards, snakes, alligators, etc.) • Aves – feathers; paired wings and legs (birds) • Mammalia – hair, mammary glands, two paired appendages

9. Task 3: Invertebrate Chordates • examine the preserved specimens and models, note the following: • Urochordata – tunicate or sea squirt • sessile adult; cellulose tunic, holdfast, siphons, pharynx • image on following slide….

11. Task 3: Invertebrate Chordates • examine the preserved specimens and models, note the following: • Cephalochordata – lancelet or Amphioxus • specimen, model, and slide; match to Figs. 8-2 and 8-3 • note oral hood, fins, myotomes, dorsal nerve cord, notochord, pharynx, pharyngeal gill slits, postanal tail; other items from figures

12. Task 4: Vertebrate Chordates • obtain a “vertebrate box” and examine the preserved specimens, note the following: • Agnatha – brook lamprey • jawless; single median dorsal and caudal fins (no paired lateral fins); 7 pairs of external gill slits • Chondrichthyes – shark • scales (makes sandpapery skin); various fins (note especially those in pairs); claspers on pelvic fins of mature males; cloacal opening

13. Task 4: Vertebrate Chordates • obtain a “vertebrate box” and examine the preserved specimens, note the following: • Osteichthyes – yellow perch • scales, operculum over gills, various fins (note pairs); lateral lines (from operculum to caudal fin) • Amphibia – leopard frog and salamander • smooth skin (no scales); 4 legs – count digits; tympanum on frog; eyelids (do other box items have eyelids?)

14. Task 4: Vertebrate Chordates • obtain a “vertebrate box” and examine the preserved specimens, note the following: • Reptilia – green anole lizard, turtle, and garter snake • scaly skin, 4 legs (reduced to vestigial in snake); lizard – claws, eyelids; turtle – carapace and plastron • Aves and Mammalia – no specimens • demonstration table – identify specimens by class

15. TODAY YOU WILL HAVE AN EXIT ACTIVITY!!! LOOK FOR THE NOTE ABOUT THE LAB FINAL