Adaptation and Karyotype in Amphibia

Abstract

The living Amphibia seem morphologically and physiologically specialized for highly uncertain and heterogeneous environments, a condition achieved precociously in their evolutionary history; in agreement with this fact, they show high levels of genetic variability. Also two important karyological characters of the Amphibia can be easily interpreted as adaptive: The karyotype morphology, showing rather precise evolutionary trends toward symmetrical formulas in many and indipendent groups of the three orders which implies the action of strong selective factors canalizing the chromosomal differentiation; and the genome size, showing close relationships with ecological, developmental or metabolic characters having an adaptive value. © 1977 Taylor & Francis Group, LLC.