Four wet legs need not damp evolution.
Prof. Mumblebard claims: “In the evolution of vertebrates from fishes to mammals, amphibians represent the primitive stage of transition from water to land. To this day, amphibians remain limited by their ancestral dependence on water in the larval stage. Although the adults usually leave the water to bask and forage, the larvae usually still respire by means of gills and tend to be confined to ponds and streams. One way in which various amphibians have reduced their reproductive ties to water-bodies is to practise diverse methods of parental care which keep the larvae well hydrated despite hatching and developing out of the water. Living amphibians show far more parental care than living reptiles, mainly as a compensation for an evolutionary hangover.”
Robin and the Honey Badger respond:“Far from suffering from an evolutionary hangover, living amphibians are competitively superior, having managed to usurp some of the most important niches on Earth where freshwater meets land. The unique adaptations of amphibians for straddling this boundary give them particular advantages in water-bodies too unreliable for fishes such as vernal pools, floodplains and marshes. Indeed, the life histories of contemporary amphibians represent an acme of exploitation of salt-free environments in which there is enough water to boost productivity but enough drainage to maintain terrestrial vegetation. One important aspect of amphibian biology is that various amphibians show not only parental care but devotion by the father as opposed to the mother. This paternal care of offspring – known by biologists but not previously interpreted ecologically – occurs in far more families, genera and species of frogs than of mammals or reptiles. Superiority of amphibians in fatherly care is hardly explained by emancipation from water but is consistent with the longevity of amphibians compared with mammals or reptiles of similar body sizes. Based on their life histories, amphibians emerge as having a remarkable combination of longevity and fecundity. That amphibians are ecologically successful because of, not despite, their association with freshwater is borne out by the observation that no amphibious mammal, reptile or bird rivals tadpoles in the harvesting of microbes – the most productive food in wetlands. In summary, amphibian larvae depend on water not in retention of an archaic pattern but in exploitation of ecological niches in which other Classes of vertebrates are inept competitors.”
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