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MASS EXTINCTIONS AND BIODIVERSITY LOSS 181
single islands (e.g. the dodo) or in extreme 3 Investigate one of the “other” mass extinc-
conditions (e.g. the Great auk). Perhaps more tions not covered in detail here: end-Ordo-
widespread species such as pigeons, sparrows vician, Late Devonian and end-Triassic.
and chickens will survive such depredations? 4 Calculate the relative magnitudes of the
But recall the Passenger pigeon – it should big five events from Jack Sepkoski’s data-
have been immune to extinction. The other base of fossil genera, either through http://
point is to query whether it is right to extrap- strata.ummp.lsa.umich.edu/jack/ or http://
olate the figures from bird and mammal geology.isu.edu/FossilPlot/.
extinctions to the rest of life. Species of birds 5 Why is the current loss of species on
and mammal are short-lived (i.e. they evolve Earth sometimes termed the “sixth
fast), and perhaps their extinction rates are extinction”?
not appropriate for insects and plants, for
example.
The jury is still out on modern extinction. Further reading
It is clear that surging human population and
increasing tension between development and Benton, M.J. 2003. When Life Nearly Died. W.W.
Norton, New York.
ecology put pressure on natural habitats and Benton, M.J. & Twitchett, R.J. 2003. How to kill
on species. Plants and animals are dying out (almost) all life: the end-Permian extinction event.
faster now than at times in the past when the Trends in Ecology and Evolution 18, 358–65.
global human population was smaller. Pale- Briggs, D.E.G. & Crowther, P.R. 2001. Palaeobiology,
ontologists and ecologists have an important A Synthesis, 2nd edn. Blackwell, Oxford, UK.
job to do in seeking to understand just what Erwin, D.H. 2006. Extinction: How Life on Earth
the threats are and how fast the modern Nearly Ended 250 Million Years Ago. Princeton Uni-
extinction is proceeding. versity Press, Princeton, NJ.
Gotelli, N.J. & Colwell, R.K. 2001. Quantifying biodi-
versity: procedures and pitfalls in the measurement
and comparison of species richness. Ecology Letters
Review questions 4, 379–91.
Hallam, A. & Wignall, P.B. 1997. Mass Extinctions and
1 How do paleontologists and other earth their Aftermath. Oxford University Press, Oxford,
scientists study mass extinctions? Carry UK.
out a census of papers about the Permo- Hammer, Ø. & Harper, D.A.T. 2005. Paleontological
Triassic event published in the last year. Data Analysis. Blackwell Publishing, Oxford, UK.
Find the first 50 papers using any biblio- Jablonski, D. 2005. Mass extinctions and macroevolu-
graphic search tool, and classify them by tion. Paleobiology 31, 192–210.
broad theme (paleontology, stratigraphy, Taylor, P. 2004. Extinctions in the History of Life. Cam-
geochemistry, atmospheric modeling, vol- bridge University Press, Cambridge, UK, 204 pp.
canology), geographic region (perhaps by
continents), sedimentary regime (marine,
terrestrial) and key conclusion about the References
extinction model (eruption of Siberian Alvarez, L.W., Alvarez, W., Asaro, F. & Michel, H.V.
Traps, gas hydrate release, acid rain, 1980 Extraterrestrial cause for the Cretaceous-
anoxia, meteorite impact). How are our Tertiary extinction. Science 208, 1095–108.
views perhaps biased by limited geo- Bambach, R.K. 2006. Phanerozoic biodiversity mass
graphic coverage, a major focus on marine extinctions. Annual Review of Earth and Planetary
rocks and dominant academic discipline? Sciences 34, 127–55.
Are these biases to be expected, and Benton, M.J. 1995. Diversification and extinction in the
why? history of life. Science 268, 52–8.
2 Is there any evidence that the media dis- Hammer, Ø. & Harper, D.A.T. 2005. Paleontological
torts research agendas? Look at news Data Analysis. Blackwell Publishing, Oxford, UK.
stories about the KT event, and consider Jablonski, D. 2005. Mass extinctions and macroevolu-
tion. Paleobiology 31, 192–210.
the balance of reporting of different Jin, Y.G., Wang, Y., Wang, W., Shang, Q.H., Cao, C.Q.
aspects: do a census of the animal and & Erwin D.H. 2000. Pattern of marine mass extinc-
plant groups mentioned in the fi rst 50 tion near the Permian-Triassic boundary in South
news reports you encounter. China. Science 289, 432–6.
