
Concept explainers
Introduction:
The lophotrochozoans are the descendants of one common ancestor. The name lophotrochozoa is because of the morphological traits found in these animals, the lophophore and the trochophore.

Answer to Problem 1TYK
Correct answer:
The lophophore is a structure found in 3 phyla out of the 13 phyla, categorized under the lophotrochozoans. The mouth is ringed by tufts and helps in suspension feeding.
Explanation of Solution
Explanation/Justification for the correct answer:
Option (a) is given as a filter-feeding specialized structure. The lophophore is a structure that helps in suspension feeding and bears tufts. This structure is found in phoronids, bryozoans, and brachiopods. Hence, Option (a) is correct.
Explanation for incorrect answer:
Option (b) is given as a single opening in species with a blind gut. The lophophore is a feeding structure, so it is not a single opening in species. So, it is an incorrect option.
Option (c) is given as a distinctive type of larva with a band of cilia. It is not a particular type of larva as it is only a feeding structure present in the lophotrochozoans. So, it is an incorrect option.
Option (d) is given as a synapomorphy that defines lophotrochozoans. Spiral cleavage in these organisms is a synapomorphy. Lophophore is a feeding structure rather than a synapomorphy. So, it is an incorrect option.
Hence, options (b), (c), and (d) are incorrect.
The lophophore is present around the mouth as a ring of tentacles, which are ciliated. The food particles present in the water are taken up by the water currents to draw food.
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Chapter 31 Solutions
Biological Science, Loose-leaf Edition (7th Edition)
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