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Questions and Answers
What is the defining feature of Class Crinoidea?
What is the defining feature of Class Crinoidea?
How many species are there in Class Ophiuroidea?
How many species are there in Class Ophiuroidea?
2000
What is a characteristic feature of sea urchins in Class Echinoidea?
What is a characteristic feature of sea urchins in Class Echinoidea?
What type of environment do sea cucumbers from Class Holothuroidea inhabit?
What type of environment do sea cucumbers from Class Holothuroidea inhabit?
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Which of the following classes do sea stars belong to?
Which of the following classes do sea stars belong to?
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What is a unique behavior of the Class Holothuroidea?
What is a unique behavior of the Class Holothuroidea?
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Study Notes
Class Crinoidea - The Crinoids
- Comprises sea lilies and feather stars, known for their sessile adult stage.
- Adults attach to rocks or the ocean floor using a long stalk.
- Possess five main arms that can branch out to form up to 200 additional arms.
- Have sticky tube feet at the arm's end for filtering small organisms and aiding in respiration.
- Unique morphology: mouth faces upward, contrasting with other echinoderms.
Class Ophiuroidea
- Largest echinoderm class, featuring around 2,000 species of basket stars and brittle stars.
- Characterized by long, narrow arms enabling faster movement compared to other echinoderms.
- Primarily inhabit ocean floors, often found under stones or within crevices in coral reefs.
Class Echinoidea
- Includes approximately 900 species like sea urchins and sand dollars.
- Sea urchins adapted to hard sea bottoms utilize tube feet for movement and possess five teeth surrounding their mouth for scraping algae.
- Sand dollars inhabit sandy coastal areas, using tube feet to collect food settling around their bodies.
Class Holothuroidea
- Comprises sea cucumbers, notable for their armless structure.
- These echinoderms live on the sea bottom, crawling or burrowing into soft sediments.
- Feature modified tube feet that form tentacles around their mouth to sweep food closer.
- Unique defensive behavior: capable of evisceration, releasing digestive organs for protection.
Class Asteroidea
- Known as sea stars, this group is distributed in coastal waters worldwide.
- Exhibit a variety of colors and shapes.
- Economically significant as they prey on oysters, clams, and other commercially valuable organisms.
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Description
Explore the fascinating world of Crinoidea, known as the crinoids, which includes sea lilies and feather stars. Learn about their unique structure, feeding mechanisms, and their role in marine ecosystems. This quiz will test your knowledge on these intriguing echinoderms.
