Organismal Biology Laboratory-Kingdom Animalia Phyla Mollusca and Annelida NAME:

Question

Organismal Biology Laboratory-Kingdom Animalia Phyla Mollusca and Annelida NAME: Questions and Problems 1. Suppose you were walking nspection proved unable to retract its eyesta?ks because they were greatly swollen and knobby. Moreover, these eyestalks (tentacles) appeared to pulsate and emit light when you handled the snail. When you took this unusual snail back to the lab and dissected it you found that the peculiar appearance of the eyestalks was due to the presence of brightly colored trematode sporocysts which contained infective cercaria. Explain what's going on with this snail. in the woods and came upon a land snail which on close 2. Clams, mussels and oysters can avoid predation by using their adductor muscles to tightly close their shells. Are there any other advantages to being able to close the shell tightly? What are the disadvantages of closing the shell tightly? 3. Why are the spatial relations in the squid so confusing? When the animal swims one end goes forward first. Why not call that the anterior end (instead of dorsal)? Alternatively, the eyes, mouth and tentacles are found at one end. Why not call that the anterior end?

Explanation / Answer

Question 1 answered

The trematode Bucephalus polymorphous completes its life cycle in two hosts -snails and fish. The snail here must have been infected by Miracidium form of the trematode which is free-living form. Upon infecting the snail there it develops into sporocyst and performs asexual reproduction giving daughter sporocysts (hence the swelling ) these sporocysts then produces Cercariae which you obtained after dissection.

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