In this page I am giving links to reports by scientists who are studying and dating early plants and animals. In my page on Hominids I give similar research into early ancestors of modern humans.
Until recently, it was thought that ichthyosaurs declined gradually in diversity through multiple extinction events during the Jurassic period. These successive events were thought to have killed off all ichthyosaurs except those strongly adapted for fast-swimming life in the open ocean. Due to this pattern, it has been assumed that ichthyosaurs were constantly and rapidly evolving to be ever-faster open-water swimmers; seemingly, there was no 'stasis' in their long evolutionary history.
A small, bird-like North American dinosaur incubated its eggs in a similar way to brooding birds -- bolstering the evolutionary link between birds and dinosaurs, researchers at the University of Calgary and Montana State University study have found.
Led by University of Toronto Mississauga paleontologist Robert Reisz, an international team of scientists from Canada, Taiwan, the People's Republic of China, Australia, and Germany excavated and analyzed over 200 bones from individuals at different stages of embryonic development.