The evolution of metamorphosis in amphibians.
A survey is provided of the external transformations that coincide with metamorphosis or a water-to-land transition, and of transformations during water-to-land transition in the retinal projection, the brain stem, the lateral-line system, and the inner ear of amphibians. Among the three orders of amphibians, the frogs are characterized by more pronounced transformations during the water-to-land transition than are the other two orders. Some of the progressive and regressive changes in the sensory and nervous system are presented and a scenario is suggested for the evolution of these transformations among amphibians. Suggestions that metamorphosis in frogs can recapitulate the water-to-land transition of ancestral amniotic vertebrates are refuted.
Fritzsch
B
B
Department of Neuroscience, Scripps Institute for Oceanography, University of California, La Jolla.
D000650:Amnion / Q000502:physiology; D000663:Amphibians / Q000254:growth & development*; D000818:Animals; D005075:Biological Evolution; D001933:Brain Stem / Q000166:cytology; D002455:Cell Division; D004557:Electric Organ / Q000254:growth & development; D006198:Hair Cells, Auditory / Q000166:cytology; D008465:Mechanoreceptors / Q000254:growth & development; D008675:Metamorphosis, Biological; D009474:Neurons / Q000502:physiology; D012160:Retina / Q000254:growth & development / Q000502:physiology; D009435:Synaptic Transmission