Vertebrate Diversity Quiz

    In lab this week, we took the vertebrate diversity quiz.  I am very skeptical of one of the questions.  The question asked about the origin of bony and cartilaginous fish.  The answer choices were something like “evolved from a single jawed ancestor,” “originated in freshwater,” “diverged 425 mya,” and “all of the above.”  The correct answer on the quiz key is all of the above.  However, the aquatic  vertebrate module harped on the ostracoderm as being the origin of diverging fish lineages, so I immediately thought of the ostracoderm as being the “single jawed ancestor.”  However, the ostracoderm is jawless.  I am asking… did anyone else think that the answer is wrong and should be revised?  I believe the first answer choice should be changed to “evolved from a single jawless ancestor.”

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