EXERCISE 4.1: Anatomy of a Freshwater Mussel

1. Draw the external features of a freshwater mussel and label the structures listed in the Protocol.
2. Draw the internal features of a freshwater mussel and label the structures listed in the Protocol. Show both valves in this drawing. (a) Imagine this is the first time you have seen a clam. From the observations you have made, what evidence would indicate whether this animal is aquatic or terrestrial?

EXERCISE 4.2: Anatomy of a Fish

1. On the diagram label the external structures listed in the Protocol. Draw in any features that are missing on the diagram below.
2. Draw the internal features of a fish and label the structures listed in the Protocol.
3. Answer the following questions about your fish. (a) Name the non-paired fins. _______________________________________ (b) Name the paired fins. ___________________________________________

EXERCISE 4.3: Anatomy of a Crayfish

1. On the drawings provided, label the external structures of a crayfish listed in the Protocol.
2. On the drawing provided, label the internal structures of a crayfish listed in the Protocol.

EXERCISE 4.4: Anatomy of a Sea Urchin

1. On the diagram of the sea urchin label the external aboral structures listed in the Protocol.
2. On the diagram of the sea urchin label the external oral structures listed in the Protocol.
3. On the diagram of the sea urchin label the internal structures listed in the Protocol.

(a) Of the organisms you studied in the lab today, which one are you most closely related to and why?