GEOL 107 Lecture Notes - Lecture 27: Crown Group, Oligocene, Basilosaurus
13 Nov 2017
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Paleogene radiation - mammals inherit the world: dinosaurs - a reprise. Dinosaurs first appeared in the late triassic, and dominated the terrestrial realm throughout the rest of the mesozoic. High degree of continental proximity (late stages of pangea and then gondwana) Greenhouse world. with little variation in temperatures from the tropics to the poles. With the notable exception of late cretaceous carnosaurs (see lecture 22), dinosaur assemblages of the same age anywhere in the world are similar at even the species level. Dinosaurs ruled the world for 165 million years (late triassic to the end of the cretaceous) Their triassic initiation, jurassic-cretaceous success, and terminal cretaceous extinction are all consequences of mass extinction events. Permian world dominated by synapsids, especially the theraspids. First animals to achieve partial thermoregulation, which gave them a significant advantage over the diapsids (which were all still ectotherms) Synapsids were on the way to mammals, some had even evolved fur (diorama #18)
