Everett Claire Olson (November 6, 1910 – November 27, 1993) was an American zoologist, paleontologist, and geologist noted for his seminal research of origin and evolution of vertebrate animals.[1][2][3] Through his research studying terrestrial vertebrate fossils he identified intervals of extinction in the Permian[4] and Triassic.[5] He developed the concept of chronofauna, which he defined as "a geographically restricted, natural assemblage of interacting animal populations that has maintained its basic structure over a geologically significant period of time".[6] He also proposed stratigraphic correlations between North American (especially the Chickasha and San Angelo Formations) and Russian vertebrate-bearing strata[4] for which additional support was found much later.[7][8][9] The drop in terrestrial vertebrate diversity he proposed in at the end of the Kungurian stage of the Permian period that occurred 270 million years ago now carries his name - Olson's Extinction. Alternatively, some scientists think that the change was gradual but that it looks abrupt because of a gap in the fossil record, called "Olson's Gap".[10][8][11][12] Some of his other notable research also included the taxa Slaugenhopia,[13] Trimerorhachis, and Waggoneria.[14]
Olson was a former chair of the department of Biology at the UCLA,[1][2] a member of the National Academy of Sciences,[1][2] a recipient of Paleontological Medal of the Paleontological Society (1987),[2] the first recipient of the Romer-Simpson Medal of the Society of Vertebrate Paleontology,[2] a CSEOL Distinguished Scientist (1991).[2] University of California said that Olson "was an internationally recognized pioneer in studies of the origin and evolution of vertebrate animals".[2] The University of Chicago said that he "carried out pioneering research on the evolution of terrestrial ecosystems".[3] The National Academy of Sciences said that he ranked "among the great vertebrate paleontologists of the twentieth century".[1]
Olson was born in Waupaca, Wisconsin and grew up in Hinsdale, Illinois. Olson received his undergraduate and graduate degrees, including Ph.D. in geology (1935) from the University of Chicago.