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STUDENT OBJECTIVE

Students study the anatomy of a sea star, a tunicate, amphioxus, and perch.

EQUIPMENT	AMOUNT
	(Class of 24 with 8 groups)
Compound microscope Dissecting microscope	1/student 1/student
MATERIALS
Dissection pan Dissection instruments: scissors, forceps, blunt probe, razor blades (2) or scalpel, pins Slides Lens tissue Coverslips, #1 medium square Preserved specimens Sea star (CBS#P331D)* Demonstration Echinoderm Collection (CBS#P385)* Demonstration Tunicate Collection (CBS#P1204F)* Demonstration Amphioxus (CBS#1250C)* Perch (CBS#P1410KD)* Prepared slides Sea star arm, cross section (CBS#30-8212)* Sea star pedicellaria (CBS#30-8206)* Ascidian tadpole larva, whole mount Branchiostoma (amphioxus), whole mount (CBS#30-8316)* Branchiostoma (amphioxus), cross section (CBS#30-8346)*	24/lab   24 sets/lab 2/student 1 pkg/lab 1 box/lab 1/student 1/lab 1/lab 1/student 1/student   1/student 1/student 1/student 1/student 1/student

*Please refer to the Appendix for name and address of supplier.

PREPARATION

Six to Eight Weeks before Lab

If prepared slides are not on hand, an order should be placed for immediate delivery. All preserved specimens should also be ordered at this time. Upon arrival, they should be checked for useability in the lab. Any poorly stained and/or poorly prepared slide should be returned.

One Week before Lab

Check to see that dissection equipment is complete and instruments sharp.

CLASSROOM SUGGESTIONS

1. Students can share microscope slides, reducing the number that must be purchased.
2. This exercise is enhanced if slides, films, or filmloops on diversity are shown at the conclusion of the lab. A slide show on diversity can be run continuously during the day in a hallway showcase using a rear projection, automatic projector (Caramate). Or, if the library has a media center, a tape-slide show can be on reserve for out-of-class viewing.
3. Check out the links for this lab topic at http://auth.mhhe.com/biosci/genbio/dolphin/ You will find useful materials for developing your lab introduction or summary, and in some cases, you may want to tell students to connect to a particular site for further information.

ANSWERS TO CRITICAL THINKING QUESTIONS

1. Echinoderms lack a bilaterally symmetrical, mobile adult stage (adult motility is at best sluggish), cephalization, specialized sense organs and segmentation. As well, the circulatory system is poorly developed and the nervous system is rudimentary. Gametes are shed into the water where fertilization is random.
2. Both are elongated organisms adapted for swimming. Both possess a notochord and a dorsal nerve cord.
3. Sea squirts and eagles are classified as chordates because they both have the basic characteristics of the phylum: notochord, dorsal hollow nerve cord, gill slits, and a post anal tail at some stage in their development.

SUPPLEMENTAL MATERIALS