Questions and Answers
What does 'Class Gastropoda' mean?
Which of the following are characteristics of Class Gastropoda? (Select all that apply)
Which animals are included in Class Gastropoda?
What type of foot do gastropods have?
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How many nephridia do gastropods typically have?
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Where is the head of a gastropod located?
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What type of shell do most gastropods have?
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What is the function of a gastropod's shell?
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What gastropod has lost its shell?
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What is the term for the part of the animal that attaches to the shell?
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Most gastropods have a _____ shell.
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What is the first shell layer formed by the mantle?
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What is the second shell layer formed by the mantle?
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What is the third shell layer formed by the mantle?
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What is the term for the structure that closes the mantle cavity in gastropods?
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Where is the anus typically located in gastropods?
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What does osphradia detect?
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Where is the large digestive gland located?
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What is the Radula?
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Match the following layers of the shell with their description:
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Study Notes
Class Gastropoda Overview
- Derived from terms meaning "stomach" and "foot," indicating unique body structure.
- Characterized by asymmetry, torsion, and a muscular creeping foot.
Key Characteristics
- Structure includes a single spirally coiled shell.
- Well-developed head featuring eyes and 1-2 pairs of tentacles.
- Possess 1-2 nephridia and an anterior mantle cavity.
- Represent the most diverse class within the Phylum Mollusca.
Classification & Examples
- Includes organisms such as snails, slugs, conchs, whelks, sea hares, and nudibranchs.
- Nudibranchs are notable for being gastropods without shells.
Shell Structure and Layers
- Gastropod shells are typically spirally coiled and calcareous.
- Shell formation involves three layers:
- Periostracum (outer layer, proteinaceous).
- Prismatic layer (middle layer with long crystals).
- Nacreous layer (inner layer, flat and brick-like).
- The shell primarily serves to protect the soft body.
Shell Orientation and Identification
- Most gastropods have a dextral (right-handed) shell, while left-handed shells are rare and may arise from mutations.
- Identification of shell handedness can be done by grasping the columella with the hand.
Anatomical Features
- The operculum acts as a protective "door" to the mantle cavity.
- The anatomy includes a large digestive gland adjacent to the stomach and osphradia for chemical detection.
- The radula functions as a feeding organ, formed of 100s of teeth, and can exhibit variations in shape and structure.
Torsion
- Describes the twisting of the body during development, leading to the mouth and anus being positioned at opposite ends.
- The placement of the anus above the head enhances protection for the nervous system.
Feeding Habits
- Gastropods exhibit diverse feeding behaviors:
- Grazers (herbivores), suspension feeders, scavengers, detritivores, carnivores, and parasites.
- The radula is often adapted for specific feeding types and may be absent in some.
Subclassifications
- Prosobranchia features a thick coiled shell, anterior mantle cavity, and varied radula.
- Order Archaeogastropoda represents the oldest, more primitive forms of gastropods.
These notes encapsulate the essential aspects of Class Gastropoda, focusing on their biology, anatomy, feeding, and classification.
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Description
Explore the fascinating world of Class Gastropoda within the Phylum Mollusca. This quiz covers key characteristics, definitions, and examples of members in this diverse class, including snails and slugs. Test your knowledge and learn about the unique traits that define these creatures.
