Campbell Biology (11th Edition)

Published by Pearson
ISBN 10: 0-13409-341-0
ISBN 13: 978-0-13409-341-3

Chapter 33 - 33.3 - Concept Check - Page 703: 3


The muscular foot found in some form in all molluscs serves as the foot of the organism in a gastropod, but in a cephalopod it has been changed over time into an organ which can contract and shoot water for purposes of locomotion. In both cases the same ancestral structure sits in the same basic part of the organism and contains abundant muscle for locomotion, but evolution has changed the way that this works-- Especially compared to the use of the foot in bivalves for opening and closing the shell.

Work Step by Step

See Fig. 33.15 and the text on pp. 693-696 for descriptions of the foot in general and of the way that gastropods and cephalopods move. Use your imagination to see how the foot in each of the two cases mentioned in the question shows a differently evolved role for the foot but the retention of some ancestral/general structure (reliance on lots of contracting muscle).
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.