A marine biologist photographs a comb jelly at night.
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A marine biologist photographs a comb jelly at night. It has the usual eight rows of comb plates, and she counts plates in each row. (a) How many comb plates does the animal have? (b) She notices that the animal glows. What is this property called? (c) Can this animal reproduce by budding? Explain.
Need a reminder? The key ideaShow
Porifera: cellular level; water enters by ostia, passes the collar cells (choanocytes) in the spongocoel and leaves by the osculum; spicules or spongin; hermaphrodite. Cnidaria: cnidoblasts with nematocysts; gastro-vascular cavity with one opening; polyp (Hydra, Adamsia) and medusa (Aurelia); metagenesis in Obelia; Physalia, Pennatula, Gorgonia, Meandrina. Ctenophora: eight rows of comb plates, bioluminescence, only sexual reproduction; Pleurobrachia, Ctenoplana.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The plates. comb plates.
Step 2. The glow. Giving out light is bioluminescence, which is well marked in comb jellies.
Step 3. Budding. No. Comb jellies reproduce only sexually, so they do not bud.
Answer: (a) comb plates; (b) bioluminescence; (c) no, they reproduce only sexually.
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