The major change in the evolutionary lineage leading to the chordates was the:
A) calcification of an internal skeleton.
B) development of the lophophore as an adaptation to the predatory life.
C) ability to "suck mud" (extract food from mud or sand).
D) evolution of the water vascular system.
E) enlargement of the pharyngeal gill slits for feeding.

Question

Quizplus · Accepted Answer

The major evolutionary change leading to chordates was the enlargement of the pharyngeal gill slits for feeding. This adaptation allowed for more efficient filter feeding in aquatic environments, a key development in the evolution of chordates.

The Major Change in the Evolutionary Lineage Leading to the Chordates