AMPHIBIANS TO REPTILES

No satisfactory candidates exist to document this transition. There are fossil amphibians called Seymouria that have some reptile-like skeletal characteristics, but they appear too late in the fossil record and recent evidence indicates that they were true amphibians. The transition is in any case one which would be hard to confirm with fossils, because the most important difference between amphibians and reptiles involves the unfossilized soft parts of their reproductive systems. Amphibians lay their eggs in water and the larvae undergo a complex metamorphosis before reaching the adult stage. Reptiles lay a hard shell-cased egg and the young are perfect replicas of adults on first emerging. No explanation exists for how an amphibian could have developed a reptilian mode of reproduction by Darwinian descent.