Podcast
Questions and Answers
Which characteristic is unique to cnidarians?
Which characteristic is unique to cnidarians?
- Complete digestive system
- Cnidocytes with nematocysts (correct)
- Triploblastic development
- Bilateral symmetry
All cnidarians alternate between the polyp and medusa body forms during their life cycle.
All cnidarians alternate between the polyp and medusa body forms during their life cycle.
False (B)
Describe the function of cnidocils in cnidocytes.
Describe the function of cnidocils in cnidocytes.
trigger the firing of the nematocysts
Cnidarians are ______, meaning they have two germ layers.
Cnidarians are ______, meaning they have two germ layers.
Match the following classes of Cnidaria with their predominant body form or characteristic:
Match the following classes of Cnidaria with their predominant body form or characteristic:
Phylum cnidaria includes animals that show _____ or _____ symmetry and are _____.
Phylum cnidaria includes animals that show _____ or _____ symmetry and are _____.
Cnidarians contain specialized cells known as _____ containing organelles called _____.
Cnidarians contain specialized cells known as _____ containing organelles called _____.
What two distinct body plans do cnidarians display?
What two distinct body plans do cnidarians display?
Match the cnidarian characterisics
Match the cnidarian characterisics
Name four examples of Class Anthozoa.
Name four examples of Class Anthozoa.
Name the four classes of phylum Cnidaria.
Name the four classes of phylum Cnidaria.
Class scyphozoa has a _____ lifecycle.
Class scyphozoa has a _____ lifecycle.
Match the classes with their characteristics.
Match the classes with their characteristics.
Name two species of Class Hydrozoa.
Name two species of Class Hydrozoa.
What is a defining characteristic of a Scyphozoa?
What is a defining characteristic of a Scyphozoa?
What are three defining characteristics of Class Cubozoa that differentiates it from Class Scyphozoa?
What are three defining characteristics of Class Cubozoa that differentiates it from Class Scyphozoa?
What class of Cnidarians is the most venomous?
What class of Cnidarians is the most venomous?
Flashcards
Phylum Cnidaria
Phylum Cnidaria
A group of aquatic animals with specialized stinging cells called cnidocytes.
Cnidocytes
Cnidocytes
Specialized cells in Cnidarians that contain nematocysts for stinging.
Nematocysts
Nematocysts
Organelle within cnidocytes that ejects a coiled thread for immobilizing prey.
Polyp vs Medusa
Polyp vs Medusa
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Class Anthozoa
Class Anthozoa
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Study Notes
Phylum Cnidaria
- Includes animals with radial or biradial symmetry, are diploblastic
- Nearly all are marine (about 99%)
- Contain specialized cells called cnidocytes ("stinging cells")
- Cnidocytes contain nematocysts (stingers) containing coiled threads
- Outer cell wall has hairlike projections (cnidocils) that are sensitive to touch
- Threads penetrate and release toxins to immobilize prey or predators
- Two body forms: polyp (sessile) and medusa (motile)
- Life cycle alternates between both forms in some species
Cnidarian Body Forms
- Polyp: Sessile, cylindrical, mouth and tentacles face up
- Medusa: Motile, bell-shaped, mouth and tentacles hang from the bell
Class Anthozoa
- Polyp body plan only (no medusa stage)
- Includes sea anemones, sea pens, and corals
- Estimated 6,100 described species
- Cylindrical shape, attached to a substrate
- Mouth opening surrounded by tentacles with cnidocytes
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Description
Explore the fascinating world of Phylum Cnidaria, including their radial symmetry, cnidocytes, and life cycle with polyp and medusa forms. Learn about Class Anthozoa and their polyp body plan, including sea anemones and corals.