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