Jack Sepkoski Research Articles

David M. Raup, 1933–2015

David M. Raup was one of the most influential paleontologists of the second half of the 20th century, infusing the field with concepts from modern biology and laying the foundation for several major lines of research that continue today: theoretical morphology, which addresses why, despite eons of evolution, the spectrum of realized biological forms is such a tiny fraction of those that are theoretically possible (1); first-order patterns in the geologic history of biodiversity, in particular whether it has increased steadily over time and what the answer implies about the biosphere and the nature of the fossil record (2, 3); mathematical modeling of evolution: for example, patterns that result from the very structure of evolutionary trees and the apparent order that emerges from stochastic processes (4); and temporal patterns of biological extinction in the history of life and their implications for the drivers of extinction and the place of Earth in the Cosmos (5⇓–7). Despite his many accomplishments, Dave was modest and not known to seek attention or proselytize. He preferred to let his research do the talking. David Raup ( Right ) and Jack Sepkoski discussing analyses of extinction rates in the early 1980s. Image … [↵][1]1Email: foote{at}geosci.uchicago.edu. [1]: #xref-corresp-1-1

Revisiting Raup: exploring the influence of outcrop area on diversity in light of modern sample-standardization techniques

Since David Raup's seminal 1976 work, paleontologists have been aware of the relationship between outcrop area and diversity. By incorporating lithologic data derived from Alexander Ronov and coworkers into our own data on areas of mapped outcrops from worldwide geologic maps, we are able to establish a quantitative connection between area of sedimentary rock exposure and diversity from the same general depositional environments. Significant power-law relations are observed at both global and continental scales of consideration. The addition of data on areas of habitable area estimated from paleogeographic maps does not substantially affect these correlations between outcrop area and diversity, indicating that the relation between outcrop area and diversity is primarily a function of sampling and not a common cause such as sea level. We observe a significant diversity-area effect, first noted by Jack Sepkoski in the marine realm. Unlike Sepkoski's, however, our diversity-area effect appears to play a substantial role in influencing diversity through time; a true global diversity signal appears to be contained in the rock record despite the impacts of variable sampling.Greater outcrop area can serve to increase estimated diversity by increasing both the sample size and the range of habitats and biogeographic provinces sampled. After standardizing for pure sampling intensity by rarefying the number of taxon occurrences, outcrop area continues to explain a substantial portion of global marine diversity. This indicates that coverage, or sampling from multiple habitats and biogeographic provinces, is even more important than sampling intensity. If we remove the effect of outcrop area from our estimate of global biodiversity, we do not observe a net increase in diversity toward the present, lending support to other studies that have not supported a substantial, long-term global increase in biodiversity during the Phanerozoic.

PRESENTATION OF THE CHARLES SCHUCHERT AWARD OF THE PALEONTOLOGICAL SOCIETY TO PETER J. WAGNER III

As a young man Peter Wagner fully expected to be receiving the accolades of his peers at this age, but he rather thought it would be in Cooperstown rather than Denver, and following a series of World Series appearances as the center fielder with the Chicago Cubs. Given the Cubs recent history he still might have a promising career with them, but Pete began his career with the Ann Arbor and East Lansing farm teams in Michigan before heading to the Show at the University of Chicago where he received his Ph.D. with Jack Sepkoski. Peter's master's work untangling the phylogenetic relationships of the lophospirid gastropods became the foundation for his dissertation on the morphologic and phylogenetic diversity of Upper Cambrian–Silurian gastropods. This work is significant for several reasons. First, he showed that convergence among some groups of gastropods was sufficiently high that one must …

Stephen Jay Gould, Jack Sepkoski, and the ‘Quantitative Revolution’ in American Paleobiology

During the 1970s, a “revolution” in American paleobiology took place. It came about in part because a group of mostly young, ambitious paleontologists adapted many of the quantitative methodologies and techniques developed in fields including biology and ecology over the previous several decades to their own discipline. Stephen Jay Gould, who was then just beginning his career, joined others in articulating a singular vision for transforming paleontology from an isolated and often ignored science to a “nomothetic discipline” that could sit at evolution’s “high table.” Over the course of a single decade, between 1970 and 1980, this transformation had in large part been accomplished. Among those most centrally involved in this process were Gould, Thomas Schopf, David Raup, and Gould’s graduate student Jack Sepkoski, all of whom made major contributions in theoretical and quantitative analysis of the fossil record and evolutionary history. Recognizing that an ideological agenda was not enough, Gould and others developed and promoted new outlets, technologies, and pedagogical strategies to nurture their new discipline. This paper describes this process of transformation, and presents Sepkoski’s education and participation as exemplary of the “new model paleontologist”, which Gould hoped to produce.

PRESENTATION OF THE PALEONTOLOGICAL SOCIETY MEDAL TO RICHARD K. BAMBACH

In 1981, a short paper was published in Nature Magazine that was among the most influential paleontological publications of the past quarter century. Officially titled “Phanerozoic Marine Diversity and the Fossil Record,” the Consensus Paper, as it has come to be known, juxtaposed several depictions of the history of Phanerozoic marine taxonomic diversity, each developed with a different protocol for data collection. Despite these differences, a robust signal emerged at three different taxonomic levels, which the authors attributed to an unmistakable—and biologically meaningful—Phanerozoic trajectory. Of course, as many of us know, this paper played—and continues to play—a remarkable role in shaping the interests of paleontologists. The four authors of the Consensus Paper, Jack Sepkoski, Richard Bambach, Dave Raup, and Jim Valentine, were a remarkable bunch. They have long been among the giants of our profession, and, over the years, they have received a number of accolades that testify to their status. To list just some of their collective honors: two are members of the National Academy of Sciences; one was a member of the Polish Academy of Sciences; two received the Schuchert Award; one received the medal of the University of Helsinki; and Richard, who already has the SEPM's Moore Medal in his trophy case, today becomes the third member of the group to be awarded the Paleontological Society Medal. So, as we honor Richard Bambach today, I think it also presents us with an opportunity to search for a common thread that might help us to understand the inherent characteristics of people who go on to especially creative careers in paleontology. Is there anything we can recognize as key characteristics—call them key adaptations if you'd like—shared by the members of this quartet? Well… of course, I've thought about this…. long and hard. They come from different socioeconomic backgrounds and …

ALLMON, W. D. & BOTTJER, D. J. (eds) 2000. Evolutionary Paleoecology. The Ecological Context of Macro evolutionary Change. xi+357 pp. New York: Columbia University Press. Price US $45.00, £29.00 (hard covers), US $25.00, £16.00 (paperback). ISBN 0 231 10994 6; 0 231 10995 4 (pb).

The word ‘palaeoecology’ was once applied to almost any palaeontological study that treated fossils as living organisms rather than simply organic shapes of utility in stratigraphy. There followed a time during which community palaeoecology – the reconstruction of ancient communities and their trophic interactions – took centre stage. We are now entering a new phase of palaeoecology epitomized by the subtitle of this book: ‘The ecological context of evolutionary change’. Just as ecologists are becoming increasingly concerned with patterns of biotic distribution on large spatial scales (‘macroecology’), so palaeoecologists are looking beyond studies of single assemblages to interpretation of ecological changes across vast stretches of geological time as a backcloth to macroevolution. This collection of 11 papers, dedicated to the late Jack Sepkoski, arose from a GSA Symposium held in 1996. Like most volumes with a similar background, it is an assortment of research papers which are varied in their generality, focus and quality. The editors …

Waiting for post-postmodernism

Waiting for post-postmodernism

Mystery of mysteries: is evolution a social construction?

With the Sokal hoax - the publication of a prominent physicist's pseudo-article in a leading journal of cultural studies - the status of science moved sharply from debate to dispute. Is science objective, a disinterested reflection of reality, as Karl Popper and his followers believed? Or is it subjective, a social construction, as Thomas Kuhn and his students maintained? This text adds to the argument, using evolutionary theory as a case study. Michael Ruse begins with such luminaries as Erasmus Darwin (grandfather of Charles) and Julian Huxley (brother of Aldous, grandson of T.S. Huxley), and ends with the work of the English game theorist Geoffrey Parker - a microevolutionist who made his mark studying the mating strategies of dung flies - and the American paleontologist Jack Sepkoski, whose computer-generated models reconstruct mass extinctions and other macro events in life's history. Ruse also considers two great popularizers of evolution, richard Dawkins and Stephen Jay Gould, as well as two leaders in the field of evolutionary studies, Richard Lewontin and Edward O. Wilson, paying close attention to these figures' cultural commitments: Gould's transplanted Germanic idealism, Dawkins's male-dominated Oxbridge circle, Lewontin's Jewish background, and Wilson's southern childhood. Ruse explicates the role of metaphor and metavalues in evolutionary thought and draws significant conclusions about the cultural impregnation of science.

J. John Sepkoski Jr. (1948-1999).

With Jack Sepkoski's sudden death from heart failure on May 1, 1999, paleontology lost one of its most important figures. In his 25–year career, Jack published more than 70 research articles, 15 of them in this journal, and an equal number of reviews, commentaries, and abstracts. He co-edited Paleobiology (1983–86), received the Schuchert Award (1983), and served as President of the Paleontological Society (1995–96). In 1997, he was elected to the Polish Academy of Sciences and in the same year received the Medal of the University of Helsinki. Further recognition would surely have followed but for his untimely death.