Practice question

Urochordate tadpole larva demonstrates regionalized chordate character expression. Anterior head-trunk houses sensory vesicle with ocellus and otolith, endostyle for feeding and pharyngeal slits, whereas caudal tail comprises notochord providing stiffness, dorsal hollow nerve cord, segmental striated muscles for sinusoidal swimming and fin. Metamorphic settlement involves tail absorption, notochord degeneration and rotation of visceral organs. Confinement of chordate support and locomotor structures to tail highlights functional compartmentalization for dispersal phase, contrasting with cephalochordates where notochord and nerve cord extend throughout body, showing partial chordate representation characteristic of Urochordata.