He identified the dinosaur from a jaw bone fragment found in the mines at Sidi Chennane, Morocco.He and his colleagues from Morocco, France, and Spain concluded the dinosaur was an Abelisaur—a type of theropod similar to the Longrich determined that its teeth were worn from a life spent biting into bone, which suggests this dinosaur was a predatory meat-eater.A consequence of this approach to the Phanerozoic periods is that the ages of their beginnings and ends can change from time to time as the absolute age of the chosen rock sequences, which define them, is more precisely determined.The set of rocks (sedimentary, igneous or metamorphic) that formed during a geologic period is known as a system, so for example the 'Jurassic System' of rocks was formed during the 'Jurassic Period' (between 201 and 145 million years ago).The following table includes all currently recognized periods.The table omits the time before 2500 million years ago, which is not divided into periods. ANSWER: Relative dating is used to determine the relative ages of geologic strata, artifacts, historical events, etc.
Without the universal acceptance of the principle of evolution, there is no chance for the serious proposal of holism.
Scientists now have accurate methods (see below ) for dating fossils.
methods rely on characteristic faunal and geological patterns to bracket the period when the fossil existed.
Seriation uses the assumption that once a tool was developed, its use would become more widespread.
Stratigraphy uses the assumption that higher layers or strata were laid down after lower layers.