Jack Sepkoski
Encyclopedia
J. John Sepkoski Jr., was a University of Chicago
paleontologist. Sepkoski studied the fossil record and the diversity of life on Earth. Sepkoski and David Raup contributed to the knowledge of extinction event
s. They suggested that the extinction of dinosaurs 65 mya was part of a cycle of mass extinctions that may have occurred every 26 million years.
, Maine
. In 1970, Sepkoski received a B.S. degree, magna cum laude, from the University of Notre Dame
. Under Stephen Jay Gould
he earned a Ph.D. in geological sciences from Harvard University
in 1977. His Ph.D. was on the field geology and paleontology of the Black Hills
of South Dakota
. From 1974 to 1978, Sepkoski taught at the University of Rochester
. In 1978 he joined the University of Chicago and became a professor in 1986. Sepkoski was also a research associate at the Field Museum of Natural History in Chicago. He died of heart failure related to high blood pressure at the age of 50.
Sepkoski is perhaps best known for his global compendia of marine animal families and genera, data sets that continue to motivate a tremendous amount of paleobiological research. Sepkoski himself explored his compendium very thoroughly. In 1981, he identified three great Evolutionary Faunas in the marine animal fossil record. Each of his Evolutionary Faunas, the Cambrian, Paleozoic, and Modern Faunas, is composed of Linnean classes of animals that have covarying diversity patterns, characteristic rates of turnover, and broadly similar ecologies. Most importantly, they sequentially replaced one another as dominant groups during the Phanerozoic
. Sepkoski modeled the Evolutionary Faunas using three coupled logistic function
s, but the underlying drivers of the prominent shift in taxonomic composition represented by the three faunas remains unknown.
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...
paleontologist. Sepkoski studied the fossil record and the diversity of life on Earth. Sepkoski and David Raup contributed to the knowledge of extinction event
Extinction event
An extinction event is a sharp decrease in the diversity and abundance of macroscopic life. They occur when the rate of extinction increases with respect to the rate of speciation...
s. They suggested that the extinction of dinosaurs 65 mya was part of a cycle of mass extinctions that may have occurred every 26 million years.
Life and work
Sepkoski was born in Presque IslePresque Isle
Presque Isle may refer to:Administrative subdivisions* Presque Isle County, Michigan* Presque Isle Township, Michigan* Presque Isle, Maine, a city** Presque Isle Air Force Base, former base* Presque Isle, Wisconsin, a town...
, Maine
Maine
Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...
. In 1970, Sepkoski received a B.S. degree, magna cum laude, from the University of Notre Dame
University of Notre Dame
The University of Notre Dame du Lac is a Catholic research university located in Notre Dame, an unincorporated community north of the city of South Bend, in St. Joseph County, Indiana, United States...
. Under Stephen Jay Gould
Stephen Jay Gould
Stephen Jay Gould was an American paleontologist, evolutionary biologist, and historian of science. He was also one of the most influential and widely read writers of popular science of his generation....
he earned a Ph.D. in geological sciences from Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...
in 1977. His Ph.D. was on the field geology and paleontology of the Black Hills
Black Hills
The Black Hills are a small, isolated mountain range rising from the Great Plains of North America in western South Dakota and extending into Wyoming, USA. Set off from the main body of the Rocky Mountains, the region is something of a geological anomaly—accurately described as an "island of...
of South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
. From 1974 to 1978, Sepkoski taught at the University of Rochester
University of Rochester
The University of Rochester is a private, nonsectarian, research university in Rochester, New York, United States. The university grants undergraduate and graduate degrees, including doctoral and professional degrees. The university has six schools and various interdisciplinary programs.The...
. In 1978 he joined the University of Chicago and became a professor in 1986. Sepkoski was also a research associate at the Field Museum of Natural History in Chicago. He died of heart failure related to high blood pressure at the age of 50.
Sepkoski is perhaps best known for his global compendia of marine animal families and genera, data sets that continue to motivate a tremendous amount of paleobiological research. Sepkoski himself explored his compendium very thoroughly. In 1981, he identified three great Evolutionary Faunas in the marine animal fossil record. Each of his Evolutionary Faunas, the Cambrian, Paleozoic, and Modern Faunas, is composed of Linnean classes of animals that have covarying diversity patterns, characteristic rates of turnover, and broadly similar ecologies. Most importantly, they sequentially replaced one another as dominant groups during the Phanerozoic
Phanerozoic
The Phanerozoic Eon is the current eon in the geologic timescale, and the one during which abundant animal life has existed. It covers roughly 542 million years and goes back to the time when diverse hard-shelled animals first appeared...
. Sepkoski modeled the Evolutionary Faunas using three coupled logistic function
Logistic function
A logistic function or logistic curve is a common sigmoid curve, given its name in 1844 or 1845 by Pierre François Verhulst who studied it in relation to population growth. It can model the "S-shaped" curve of growth of some population P...
s, but the underlying drivers of the prominent shift in taxonomic composition represented by the three faunas remains unknown.
Awards
- (1983). Charles Schuchert AwardCharles Schuchert AwardThe Charles Schuchert Award is presented by the Paleontological Society to a person under 40 whose work reflects excellence and promise in the science of paleontology .- Awardees :...
, Paleontological SocietyPaleontological SocietyThe Paleontological Society, formally the Paleontological Society of America, is an international organisation devoted to the promotion of paleontology. The Society was founded in 1908 in Baltimore, Maryland and was incorporated in April 1968 in the District of Columbia... - Elected foreign member of the Polish Academy of SciencesPolish Academy of SciencesThe Polish Academy of Sciences, headquartered in Warsaw, is one of two Polish institutions having the nature of an academy of sciences.-History:...
External links
- Miller, Arnold. (Sep. 1999). Memorial: J. John Sepkoski, Jr.: A personal reflection. Journal of Paleontology.
- NASA, Near Earth Object Program
- Sepkoski's Online Genus Database