FÓSILES: HISTORIA DE LA VIDA EN LA TIERRA

Through the study of fossils, it's possible to know the history of life in the geological past of planet Earth. The knowledge of the fossils has derived lines of investigation that help to understand the geological history of the planet. Thus, it is known that the geological time is divided based on the forms of life that inhabited the planet. Life likely originated in the early Precambrian, more than 3800 million years ago, however, the oldest fossil remains of lithified bacterial communities, known as stromatolites, date to approximately 3550 million years ago. During the Paleozoic, most of the groups of plants, invertebrates and vertebrates that are known today appeared. Among all the organisms that appear at that time, brachiopods, trilobites, and graptolites are the dominant forms. In the Mesozoic, large reptiles, such as the dinosaurs, dominated, however, the most notable index invertebrates of this time correspond to ammonites and belemnites.