GEL 107 Lecture Notes - Lecture 24: First Appearance Datum, Biostratigraphy
Document Summary
Old species will be found in the bottom and top species will be relatively new. There will be different organism in each later. Example: grizzly bear locally extinct in ca, but found somewhere else. Global extinction, extirpation or emigration --- need more localities to know. Origination lived there from the beginning. Fossil hiatus lack of fossil or fossils for a period of time at a specific region. Fad first appearance datum of fossil in rock record. Lad last appearance datum of fossil in rock record. Assemblage = group of co-occurring species, could be used to characterize biostratigraphic zones. Species longevity: some species exists for as long as 25ma or as short as 1ma, species longevity varies. Taxonomic turnover: many, many taxa have originated and went extinct, newly evolved taxa sometimes replaces old and occupy similar ecology via convergent evolution. Carnivores: therapside replaced/ outcompeted by crocodylomorphs and replaced/outcompeted by theropods. Herbivores: therapsids replaced/outcompeted by rhynchosaurs and replaced/outcompeted by.
