Cnidarians_2024

What is the defining characteristic of the Phylum Cnidaria?

Cnidarians have specialized cells called cnidocytes that can produce nematocysts, used for capturing prey and defense.

Name the four main classes of Cnidaria.

Hydrozoa, Scyphozoa, Anthozoa, and Cubozoa.

What type of symmetry do Cnidarians exhibit?

Radial symmetry.

What are the two body forms of Cnidarians?

Polyp and Medusa.

What is the function of nematocysts in Cnidarians?

Nematocysts are used to capture prey and provide defense.

How do Hydrozoans reproduce?

Hydrozoans can reproduce both asexually (by budding) and sexually (through medusa).

What is the role of zooxanthellae in coral reefs?

Zooxanthellae are symbiotic algae that provide oxygen and organic carbon to corals through photosynthesis.

What are the environmental conditions necessary for hermatypic corals?

Warm temperatures (73-75°F), shallow depths (<230 feet), normal salinity (35ppt), and clear water.

What causes coral bleaching?

Coral bleaching occurs due to the loss or significant reduction of zooxanthellae, often triggered by increased sea temperatures.

Describe the life cycle of a generalized Cnidarian.

The life cycle includes an asexual polyp form and a sexual medusa form, which produces gametes that develop into ciliated larvae called planula.

What distinguishes Anthozoa from other classes in Cnidaria?

Anthozoa has only the polyp stage and no medusa stage.

What is the primary diet of Cnidarians?

Cnidarians are mostly carnivorous.

What is the importance of coral reefs in ecosystems?

Coral reefs provide habitats for many marine organisms, protect coastlines, support fisheries, and contribute to ecotourism.

What is the function of the gastrovascular cavity in Cnidarians?

The gastrovascular cavity serves as both the digestive cavity and the site of nutrient absorption.

How do Cubozoans reproduce?

Cubozoans have internal fertilization and the dominant form is the medusa.

What is a unique feature of Cubozoa that enhances their sensory capabilities?

Cubozoans have specialized structures called rhopalia which contain eyes and sensory receptors.