Cnidarians and Ctenophores

This set of flashcards covers key concepts and terms regarding Cnidarians and Ctenophores, including their classifications, anatomy, reproduction, feeding habits, and ecological relationships.

What is the Phylum Cnidaria known for?

Over 9,000 species equipped with specialized cells called cnidocytes that contain stinging organelles.

What are the two basic body plans in Cnidarians?

Polyp (sedentary) and medusa (free-swimming).

What distinguishes Hydrozoa within the Cnidaria?

Marine and colonial forms, exhibiting both polyp and medusa life cycles.

What is the function of cnidocytes in Cnidarians?

They contain stinging organelles called nematocysts used for capturing prey.

Describe the gastrovascular cavity in Cnidarians.

Acts as a stomach, where food is digested extracellularly and intracellularly.

How do Scyphozoans primarily reproduce?

Sexually, with fertilization occurring internally, leading to the formation of a planula from the zygote.

What is the typical anatomy of a Scyphozoan?

Mouth located beneath the umbrella, with a manubrium drawn out into oral lobes for capturing prey.

What type of symmetry do Ctenophores display?

Biradial symmetry, due to the presence of two tentacles.

How do Ctenophores capture prey?

Using two tentacles that contain epidermal glue cells called colloblasts.

What are the reproductive methods of Ctenophores?

They are monoecious, with fertilized eggs discharged into the water and developing into free-swimming larvae.

What is a key feature of Anthozoans?

They lack a medusa stage and are found in various marine environments.

What is the significance of mutualistic relationships in Cnidarians?

Some Cnidarians, like sea anemones, engage in mutualism with organisms like clownfish, benefiting both parties.

What is the main difference in locomotion between Cnidarians and Ctenophores?

Cnidarians can have both polyp and medusa forms, while Ctenophores are primarily free-swimming with cilia.

What is adaptive diversification in the context of Cnidarians?

The concept that Cnidarians have not deviated much from their basic structural plan despite various adaptations.

Describe the digestive process in Ctenophores.

They utilize a gastrovascular system for digestion, which includes both extracellular and intracellular processes.