Australian Lizard Evolves From Egg-Laying To Live Birth

Scientists are seeing evolution in action in the yellow-bellied three-toed skink found in Australia, as almost all those living in the colder, higher mountain regions are now giving live births while their kin in the warm coastal lowlands of New South Wales still lay eggs. This gives a rare opportunity for scientists to study the various stages of the transition from one birth style to the other. Among the things hoped to be answered by researchers of the egg-to-baby switch is nutrients sustenance of the offspring before birth. Embryos in eggs get nutrients from the yolk and shell while mammalian embryos have placentas connected to the uterus wall to give babies food and oxygen. Scientists are looking into the chemistry and structure of the lizard’s uterus and its role in the transformation of the birthing process.