Cnidarians and Ctenophores Lecture Review

These flashcards cover fundamental concepts related to Cnidarians and Ctenophores as discussed in the lecture, emphasizing their classes, structures, and evolutionary significance.

What are the main classes of Cnidarians mentioned in the lecture?

The main classes are Medusozoa (includes Hydrozoans, Scyphozoans, and Cubozoans) and Anthozoans.

What is the significance of alternation of generations in Cnidarians?

Cnidarians exhibit alternation of generations between Medusa and polyp forms.

What distinguishes Hydrozoans from Scyphozoans?

Hydrozoans are typically smaller and include forms like the Siphonophora, while Scyphozoans are the larger, more conspicuous jellyfish.

What are coloblasts and where are they found?

Coloblasts are adhesive cells found in Ctenophores (often referred to as comb jellies) used for capturing prey.

What is a unique feature of Ctenophores compared to Cnidarians?

Ctenophores lack stinging cells (cnidocytes) and use coloblasts instead.

How do Ctenophores move?

Ctenophores move using rows of fused cilia called ctenes.

What are the differences in digestive structures between Cnidarians and Ctenophores?

Ctenophores have two openings (mouth and anal pores) for waste expulsion, while Cnidarians typically have a single opening.

What evolutionary aspect sets Ctenophores apart from other groups?

Recent studies suggest Ctenophores may be more ancestral than some other groups previously considered basal.

What kind of reproduction do Ctenophores primarily use?

Ctenophores primarily reproduce through sexual reproduction and are usually simultaneous hermaphrodites.

What is ballast water and how can it lead to invasive species?

Ballast water is water taken on by ships to maintain stability, which can contain organisms that become invasive when released in new environments.

Why is DNA sequencing important in classifying new marine organisms?

DNA sequencing allows for accurate identification and classification of organisms that may not be easily recognizable based on morphology alone.