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Signal or noise? A null model method for evaluating the significance of turnover pulses

  • W. Andrew Barr (a1)

Patterns of turnover in the mammalian fossil record have been interpreted as reflecting “pulses” of originations and extinctions hypothesized to be driven by climate change. However, criteria for determining what constitutes a meaningful pulse have been idiosyncratic, and investigations of turnover patterns in mammals have yielded mixed results.

This study presents simple simulations of fossil records in which origination and extinction probabilities for each lineage are held constant. Nonetheless, the total number of turnover events per time bin varies stochastically, producing statistical “noise.” Various simulation and analytical assumptions are examined to determine their impact on the type I error rate (i.e., how often “pulses” are detected in a purely stochastic process).

Results suggest that simple analytical parameters (length of time bins and turnover-pulse criterion) have predictable and straightforward effects on false-positive rates. Furthermore, “pulses” of turnover of a magnitude similar to that observed in the terrestrial mammalian fossil record may be quite common under realistic analytical conditions.

The null turnover model offers a practical way to evaluate the significance of observed turnover events in future empirical studies of the fossil record. In evaluating the significance of a “pulse” of fossil origination or extinction events, analytical parameters can be explored using this null model to determine the approximate type I error rate for a set of parameters. Because false-positive rates are shown to be quite high, functional trait-based approaches may offer more reliable indicators of the impact of climate change on turnover dynamics.

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J. Alroy 1996. Constant extinction, constrained diversification, and uncoordinated stasis in North American mammals. Paleogeography Paleoclimatology Paleoecology 127:285311.

D. W. Bapst 2012. paleotree: an R package for paleontological and phylogenetic analyses of evolution. Methods in Ecology and Evolution 3:803807.

A. D. Barnosky , N. Matzke , S. Tomiya , G. O. U. Wogan , B. Swartz , T. B. Quental , C. Marshall , J. L. McGuire , E. L. Lindsey , K. C. Maguire , et al. 2011. Has the Earth’s sixth mass extinction already arrived? Nature 471:5157.

T. K. Baumiller 1996. Exploring the pattern of coordinated stasis: simulations and extinction scenarios. Palaeogeography, Palaeoclimatology, Palaeoecology 127:135145.

A. K. Behrensmeyer , N. E. Todd , R. Potts , and G. E. McBrinn . 1997. Late Pliocene faunal turnover in the Turkana Basin, Kenya and Ethiopia. Science 278:15891594.

F. Bibi , and W. Kiessling . 2015. Continuous evolutionary change in Plio-Pleistocene mammals of eastern Africa. Proceedings of the National Academy of Sciences USA 112:1062310628.

M. Blaauw , K. D. Bennett , and J. A. Christen . 2010. Random walk simulations of fossil proxy data. The Holocene 20:645649.

R. Bobe , and A. K. Behrensmeyer . 2004. The expansion of grassland ecosystems in Africa in relation to mammalian evolution and the origin of the genus Homo. Palaeogeography, Palaeoclimatology, Palaeoecology 207:399420.

R. Bobe , A. Behrensmeyer , and R. Chapmam . 2002. Faunal change, environmental variability and late Pliocene hominin evolution. Journal of Human Evolution 42:475497.

P. B. deMenocal 1995. Plio-Pleistocene African climate. Science 270:53.

J. T. Eronen , P. D. Polly , M. Fred , J. Damuth , D. C. Frank , V. Mosbrugger , C. Scheidegger , N. C. Stenseth , and M. Fortelius . 2010a. Ecometrics: the traits that bind the past and present together. Integrative Zoology 5:88101.

M. Foote 1997. Estimating taxonomic durations and preservation probability. Paleobiology 23:278300.

M. Foote 2000. Origination and extinction components of taxonomic diversity: general problems. Paleobiology 26:74102.

M. Foote , and D. M. Raup . 1996. Fossil preservation and the stratigraphic ranges of taxa. Paleobiology 22:121140.

M. Fortelius , I. Žliobaitė , F. Kaya , F. Bibi , R. Bobe , L. Leakey , M. Leakey , D. Patterson , J. Rannikko , and L. Werdelin . 2016. An ecometric analysis of the fossil mammal record of the Turkana Basin. Philosophical Transactions of the Royal Society of London B 371:20150232.

D. Jablonski , and W. G. Chaloner . 1994. Extinctions in the fossil record [and Discussion]. Philosophical Transactions of the Royal Society of London B 344:1117.

D. G. Kendall 1948. On the generalized “birth-and-death” process. Annals of Mathematical Statistics 19:115.

J. K. McKee 1995. Turnover patterns and species longevity of large mammals from the late Pliocene and Pleistocene of southern Africa: a comparison of simulated and empirical data. Journal of Theoretical Biology 172:141147.

J. K. McKee 2001. Faunal turnover rates and mammalian biodiversity of the late Pliocene and Pleistocene of eastern Africa. Paleobiology 27:500511.

S. Nee , E. C. Holmes , R. M. May , and P. H. Harvey . 1994a. Extinction rates can be estimated from molecular phylogenies. Philosophical Transactions of the Royal Society of London B 344:7782.

S. Nee , R. M. May , and P. H. Harvey . 1994b. The reconstructed evolutionary process. Philosophical Transactions of the Royal Society of London B 344:305311.

P. D. Polly , A. M. Lawing , J. T. Eronen , and J. Schnitzler . 2015. Processes of ecometric patterning: modelling functional traits, environments, and clade dynamics in deep time. Biological Journal of the Linnean Society 118:3963.

R. Potts 2007. Environmental hypotheses of Pliocene human evolution. In: Bobe, R., Alemseged, Z. and Behrensmeyer, A. K., editor. Hominin Environments In The East African Pliocene: An Assessment Of The Faunal Evidence. Vertebrate Paleobiology and Paleoanthropology Series. Springer. p. 2549.

P. Raia , P. Piras , and T. Kotsakis . 2005. Turnover pulse or Red Queen? Evidence from the large mammal communities during the Plio-Pleistocene of Italy. Palaeogeography, Palaeoclimatology, Palaeoecology 221:293312.

D. M. Raup , S. J. Gould , T. J. M. Schopf , and D. S. Simberloff . 1973. Stochastic models of phylogeny and the evolution of diversity. Journal of Geology 81:525542.

P. Schulte , L. Alegret , I. Arenillas , J. A. Arz , P. J. Barton , P. R. Bown , T. J. Bralower , G. L. Christeson , P. Claeys , C. S. Cockell , et al. 2010. The Chicxulub asteroid impact and mass extinction at the Cretaceous-Paleogene boundary. Science 327:12141218.

J. J. Sepkoski 1998. Rates of speciation in the fossil record. Philosophical Transactions of the Royal Society of London B 353:315326.

C. D. Thomas , A. Cameron , R. E. Green , M. Bakkenes , L. J. Beaumont , Y. C. Collingham , B. F. N. Erasmus , M. F. de Siqueira , A. Grainger , L. Hannah , et al. 2004. Extinction risk from climate change. Nature 427:145148.

B. Villmoare , W. Kimbel , C. Seyoum , C. Campisano , E. DiMaggio , J. Rowan , D. Braun , J. Arrowsmith , and K. Reed . 2015. Early Homo at 2.8Ma from Ledi-Geraru, Afar, Ethiopia. Science 347:13521355.

E. S. Vrba 1993. Turnover-pulses, the Red Queen, and related topics. American Journal of Science 293:418.

L. Werdelin , and M. E. Lewis . 2005. Plio-Pleistocene Carnivora of eastern Africa: species richness and turnover patterns. Zoological Journal of the Linnean Society 144:121144.

I. Žliobaitė , J. Rinne , A. B. Tóth , M. Mechenich , L. Liu , A. K. Behrensmeyer , and M. Fortelius . 2016. Herbivore teeth predict climatic limits in Kenyan ecosystems. Proceedings of the National Academy of Sciences USA 113:1275112756.

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