Extinction

by

Norman MacLeod

• LAST REVIEWED: 13 April 2023
• LAST MODIFIED: 28 June 2016
• DOI: 10.1093/obo/9780199941728-0078

Introduction

In 1980 an interdisciplinary research team from the University of California, Berkeley made a startling announcement in the highly respected science journal/magazine Science (cited under Journals). This report detailed the discovery of evidence that the Earth had collided with a ten-kilometer asteroid at the very end of the Cretaceous period in Earth history. The article went on to speculate that this collision had probably been the cause of the extinctions that had long been known to have occurred at that time, including the extinction of the “dinosaurs.” This was not the first time scientists had proposed an explanation for this extinction event or the extinction of this group. Indeed, this was not even the first speculation that an asteroid collision had caused a major mass extinction. However, Luis and Walter Alvarez, Frank Asaro and Helen Michel were the first to claim to have direct, physical evidence of such a collision, the first to estimate the impactor’s size and speed, and the first to estimate the range of its physical effects. Reaction was swift, from virtually immediate acceptance that this long-standing mystery of science had at last been solved to entrenched opposition to the idea that an asteroid killed off the dinosaurs. It seemed that no one could ignore the implications of this announcement, certainly not the popular press, which seemed obsessed with the link between dinosaurs and space exploration. Since 1980, the asteroid impact theory of mass extinction has been debated widely in the technical and popular literature, has spawned many thousands of peer-reviewed research reports and presentations at scientific meetings, and has been the subject of dozens of international conferences, news stories, books, and videos. Along the way, this theory unquestionably changed the scientific community’s collective mind about which types of explanations can be considered scientific as well as which constitutes a “natural” process. Supporters and opponents alike have repeatedly declared the debate over; however, it remains one of the most active and high-profile contemporary scientific controversy holding the attention of the world in a way few other scientific debates have ever done. In addition, authors have linked both scientific and popular interest in the mass extinction events of Earth’s geological past with concern about the loss of biodiversity in the modern world, dubbing it the “sixth mass extinction.”

General Overviews

Extinction research was originally pursued by different specialists using different data, subjecting these to different techniques of analysis, and achieving different, and often incompatible, results. Nitecki 1984 epitomizes this traditional approach. Nonetheless, over the last thirty years, interest in mass extinction events in deep time has progressively merged with an interest in the degree to which predicted extinction events in the modern world are similar—sometimes metaphorically, sometimes actually. This development can be traced through Novacek and Wheeler 1992; Lawton and May 1995; and MacLeod, et al. 2013, with the overviews by Hallam and Wignall 1997 and Courtillot 1999 being more focused reviews of extinction research from a geological perspective.

• Courtillot, V. 1999. Evolutionary catastrophes: The science of mass extinction. Cambridge, UK: Cambridge Univ. Press.

  A substantial expansion of a review article originally published in Ryder, et al. 1996 (cited under Conference Proceedings). Vincent Courtillot, a specialist in the dating of volcanic eruptions, used a variety of data and insights to challenge the idea that mass extinctions are caused by meteorite/comet impacts, favoring instead large igneous province (LIP) eruptions as the primary cause of these cataclysms.

• Hallam, A., and P. B. Wignall. 1997. Mass extinctions and their aftermath. Oxford: Oxford Univ. Press.

  An exhaustively referenced technical monograph and critical review of mass extinction as a phenomenon of the fossil record written by two of the most knowledgeable field paleontologists of two successive generations. Covers most of what had been written or said of importance on the paleontological side of extinction studies at the time of its publication.

• Lawton, J. H., and R. M. May, eds. 1995. Extinction rates. Oxford: Oxford Univ. Press.

  Essentially the proceedings of a 1993 Royal Society of London conference on the topic, this slim volume attempts—and largely succeeds—in critically reviewing the data, concepts, and methods (still) used by researchers to estimate and understand the meaning of extinction rates for modern species. A technical treatment in parts, but well worth the effort to penetrate.

• MacLeod, N., J. D. Archibald, and P. Levins, eds. 2013. Grzimek’s animal life encyclopedia: Extinctions. 2d ed. 2 vols. Minneapolis: Gale.

  Quite a large and up-to-date (as of the mid-2010s) collection of articles written by specialists for the nonspecialist reader on virtually all aspects of extinction studies, both ancient and modern. The level of attention paid to the social, cultural, and political aspects of the extinction issue, in addition to the more standard coverage of scientific topics, is especially noteworthy.

• Nitecki, M. H. 1984. Extinctions. Chicago: Univ. of Chicago Press.

  Published four years after the “Iridium (Ir) spike” paper by Alvarez, et al. 1980 (cited under Physical). This collection—based on a 1983 symposium held at Chicago’s Field Museum—captures some of the leaders of a paleontological community struggling to come to grips with a new neo-catastrophist extinction paradigm. In the Introduction, David Raup (a prominent proponent of neo-catastrophism) claimed “the range of views presented in this volume shows a level of disparity or downright confusion which is offscale [sic]” (p. 11).

• Novacek, M. J., and Q. D. Wheeler, eds. 1992. Extinction and phylogeny. New York: Columbia Univ. Press.

  After proponents of phylogenetic systematics dismissed the significance of the fossil record for years, these authors began the process of redressing the imbalance by demonstrating the critical role of paleontological data in understanding the phylogenetic dynamics of both extinction and radiation events, most notably through introduction of the concept of “ghost ranges” to a wide audience.