Growth in amphibians

The complex life history of many amphibians has been designed to take advantage of the resources of two completely different habitats. The aquatic free-living amphibian larva is different from the terrestrial adult regarding morphology, physiology and behavioural patterns. Therefore, in the life-time of an individual amphibian, two discontinuous growth stanzas are exhibited. The sigmoid growth model fits well with both stanzas. The rapid growth of the larval amphibian can be described by the double exponential Gompertz equation, whereas the slow growth process of the transformed amphibian can be described by the von Bertalanffy growth model. The bulk of amphibian growth occurs in the terrestrial phase and is not independent of size, age, sex and environmental conditions. The endocrine regulation of growth in amphibians is unique in the sense that the mechanism of pituitary action is different in aquatic and terrestrial phases.