Questions and Answers
Cnidaria are ______ (diplo or triploblastic)?
diploblastic
All Protostomes and Deuterostomes are _____ (diplo or triploblastic)?
triploblastic
Are cnidarians more organized than sponges?
True
Are cnidarians more sessile or motile?
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What do cnidarians feed on?
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What makes cnidarians good predators?
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What are characteristics of the phylum Cnidaria?
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What is the stinging organelle?
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When a nematocyte is fired, its stimulus can achieve a velocity of _____ and an acceleration of ______.
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Nematocytes inject ____ into prey, easily immobilizing prey.
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There are over ______ species in phylum Cnidaria. It is made up of _____ and _______.
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What is the trigger that creates osmotic pressure to effect a coil for nematocytes in cnidocytes?
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Cnidarians have the longest fossil history with specimens from over _______ years ago.
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Are cnidarians more widespread in marine or freshwater? What region are they in?
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What are some examples of mutualistic relationships between cnidarians and other creatures?
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What are the four traditional classes of Cnidaria?
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Which class is made up of hydroids, fire corals, Portuguese man-of-war?
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What is the largest class; including stony and soft corals, sea anemones?
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What class is made up of cube or box jellyfishes?
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What class is made up of true jellyfishes?
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What is the fifth class of Cnidaria? What is special about it?
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What is the word for when two different types of life forms can be presented in an organism?
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What are the two forms cnidaria can be in?
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What is the more appropriate name for jellyfish now?
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Which retains sac-like body plans? Polyps or Medusa?
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Medusa is essentially unattached polyp with tubular body widened and flattened into a _____ shape.
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The polyp form has the tubular body with the mouth facing ______ and surrounded by ______.
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In the polyp form, the mouth leads to the ____ _____.
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In the polyp form, the aboral end is connected to ______ by _____ _____.
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How do polyps reproduce asexually?
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If polyp detaches from origin, it becomes a _____.
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If the bud remains attached to the polyp that made it, it becomes ____.
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What is the form of cnidarians in medusa form?
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Study Notes
Characteristics of Phylum Cnidaria
- Cnidarians are diploblastic organisms with two cell layers.
- More organized than sponges, showing advanced morphological structure.
- Primarily sessile; some species can move.
Feeding and Predation
- Cnidarians are effective predators, able to kill and consume prey more complex than themselves.
- Their tentacles, equipped with nematocytes, aid in capturing prey.
Key Features of Cnidarians
- Possess cnidocytes that contain nematocytes, the stinging organelles.
- Exhibit radial symmetry and can exist as polyps or medusae.
- Lack excretory or respiratory systems and coelomic cavities.
- Have an incomplete digestive system, characterized by a gastrovascular cavity.
Nematocyte Functionality
- When triggered, nematocytes can achieve a velocity of 2 meters/sec and an acceleration of 40,000 times gravity.
- Inject toxins into prey, immobilizing them for consumption.
Diversity and Habitat
- Over 9,000 species exist in this phylum, including hydroids, sea anemones, and jellyfish.
- Cnidarians thrive in marine environments, particularly in warm tropical waters.
Relationships and Interactions
- Examples of mutualism include clownfish residing in sea anemones, hydroids on hermit crab shells, and defense mechanisms among various marine creatures.
Taxonomy of Cnidaria
- Four traditional classes: Hydrozoa, Scyphozoa, Cubozoa, Anthozoa.
- Hydrozoa includes hydroids and Portuguese man-of-war.
- Anthozoa encompasses stony and soft corals as well as sea anemones.
- Cubozoa represents box jellyfish, while Scyphozoa includes true jellyfish.
- Staurozoa is unique for lacking a medusa stage in its life cycle.
Body Plans and Forms
- Cnidarians exhibit a dimorphic body plan, existing as polyps or medusae.
- Polyp form is sedentary, while medusa is free-floating with a bell shape.
- Both forms retain sac-like body structures.
Reproductive Strategies
- Polyps reproduce asexually through budding, pedal laceration, or fission.
- Detached polyps develop into clones, while attached buds form colonies sharing a gastrovascular cavity.
Morphological Features
- The polyp has an upward-facing mouth surrounded by tentacles and connects to the substratum via a pedal disk.
- The medusa form is bell-shaped with a tetramerous symmetry.
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Description
Test your knowledge on Phylum Cnidaria, including sea anemones and jellyfish, with these flashcards. Each card presents a key concept related to cnidarians, such as their tissue organization and mobility. Perfect for biology students or anyone interested in marine life.