[Campbell Biology P.770] Which of the following accurately describes the changes a tunicate ... | Practice Question

Which of the following accurately describes the changes a tunicate undergoes during its metamorphosis from larva to adult, as detailed in the text?

  • A: The larva, which is free-swimming and exhibits all four chordate characters, settles on a substrate and subsequently resorbs its tail and notochord, with its nervous system degenerating.
  • B: The adult tunicate develops a prominent tail and notochord for locomotion, while its pharyngeal slits disappear as it shifts to a predatory lifestyle.
  • C: Tunicate larvae are sessile and filter-feed, while adults are free-swimming and reproduce sexually.
  • D: The metamorphosis involves the expansion of the nervous system and the development of new sensory organs to aid in substrate searching.

Explanation

The text explicitly states: 'A tunicate larva is a free-swimming but nonfeeding 'tadpole' in which all four main characters of chordates are evident.' It also describes that 'Once a tunicate has settled on a substrate, it undergoes a radical metamorphosis in which many of its chordate characters disappear. Its tail and notochord are resorbed; its nervous system degenerates; and its remaining organs rotate 90°.' This information directly supports option A.