Tetrapods are four-limbed vertebrates that evolved from lobe-finned fish during the Devonian (395 million years ago), invading the land and ultimately leading to today's the amphibians, reptiles, birds, and mammals. Read more →
Amniotes are tetrapods (four-limbed vertebrates) whose eggs contain amnions, an adaption that keeps them from drying out on land; they first appeared during the Carboniferous. There are two main groups, synapsids and sauropsids (anapsids, diapsids, and euryapsids), which differ in their evolutionary history and their skull morphologies (specifically, the types of fenestrae or "holes" in the skull). For a much more detailed look at the evolution and taxonomy of aminotes, check out Palaeofiles from the University of Bristol.
Fossils, preserved remains or traces from ancient organisms, not only paint a picture of past life, they intrigue imaginations of all ages, make classic home decorations, and perhaps most notably, power society (petroleum is a chemical fossil). This post highlights the types of fossils, the stages of fossilization, the factors that increase the likelihood of an organism becoming a fossil, as well as the methods of preservation. Read more →