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Ch. 33 - An introduction to Invertebrates
Campbell - Campbell Biology 11th Edition
Urry11th EditionCampbell BiologyISBN: 9789357423311Not the one you use?Change textbook
Chapter 33, Problem 1

A land snail, a clam, and an octopus all share
a. A mantle
b. A radula
c. Gills
d. Distinct cephalization

Verified step by step guidance
1
Begin by identifying the common phylum to which a land snail, a clam, and an octopus belong. All three are part of the phylum Mollusca.
Understand the characteristics of the phylum Mollusca. Members of this phylum typically have a mantle, which is a significant part of their anatomy.
Consider the function of the mantle in mollusks. The mantle is a layer of tissue that covers the body and is responsible for secreting the shell in many mollusks.
Evaluate the other options provided: a radula is a specialized feeding organ found in some mollusks, but not all (e.g., clams do not have a radula). Gills are present in aquatic mollusks, but not in land snails. Distinct cephalization refers to the development of a head region, which is more pronounced in octopuses than in snails or clams.
Conclude that the shared feature among a land snail, a clam, and an octopus is the mantle, as it is a defining characteristic of the phylum Mollusca.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Mantle

The mantle is a significant part of mollusks, including snails, clams, and octopuses. It is a layer of tissue that covers the visceral mass and is responsible for secreting the shell in those mollusks that have one. The mantle also plays a role in respiration and excretion, making it a crucial anatomical feature across different mollusk species.
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Radula

A radula is a specialized feeding organ found in most mollusks, except bivalves like clams. It is a ribbon-like structure covered with tiny teeth used to scrape or cut food before ingestion. The presence or absence of a radula is a key distinguishing feature among mollusk classes, highlighting differences in feeding strategies.
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Cephalization

Cephalization refers to the concentration of sensory organs and nerve cells at the anterior end of an organism, forming a head region. This feature is prominent in octopuses, which have a well-developed head and brain, but is less distinct in snails and clams. Cephalization is associated with increased complexity and specialization in the nervous system, enhancing an organism's ability to interact with its environment.
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