Evolution__3rd_Edition

680 PART 5 / Macroevolution
(2002), for instance, used an unpublished update of “Sepkoski.” Sepkoski’s database
has often been criticized for taxonomic errors. Adrain & Westrop (2000) made a study
of the problem. They made an expert assessment of part of the trilobite database in
Sepkoski. They found that as many as 70% of the entries in the database were inaccurate,
but that the errors were random and did not introduce bias. See Pease (1992) on
the trend toward declining extinction rates with time.
On mass extinctions, see Hallam & Wignall (1997), particularly their overview
chapter. For the Cretaceous–Tertiary mass extinction, see the pair of papers by Alvarez
& Asaro and by Courtillot in Scientific American (October 1990) for asteroidal and
volcanic interpretations. Courtillot (1999) is a book on the topic. See Grieve (1990) on
impact craters. The other mass extinctions, including the Permian mass extinctions,
can be followed up through Hallam & Wignall (1997) and the general references on
extinction. Benton (2003) is a popular book mainly about the Permo-Triassic mass
extinction.
On fractal extinction statistics, Kirchner & Weil (1998) and Hewzulla et al. (1999)
followed the topic up, respectively more differing from and more agreeing with Solé
et al. (1997). On fractals in nature generally, see Bak (1996). On a related theme,
Hubbell (2001) looks at the clade shapes expected on random models of speciation
and extinction.
On replacements, Cooper & Fortey (1999) and Tavaré et al. (2002) give references
for the molecular work. McKinney et al. (1998) is a related analysis for the bryozoan
example. For dinosaurs and mammals, see Gould (1983, chapter 30) and Van Valen &
Sloan (1977). Gould argues for independent replacement, Van Valen and Sloan (long
before the molecular data!) for competitive replacement. Novacek (1992) reviews
mammal fossils and phylogeny. A further classic case study is the replacement of
mammal-like reptiles by dinosaurs after the Triassic mass extinction: it looks noncompetitive
(Sereno 1999). Levinton (2001) and Gould (1989) discuss the number of
higher groups through geological time.
On species selection, Gould (2002b) is now a standard source for one side of the
question. Further discussion is in, among many others: Williams (1966, 1992 a who
prefers the term “clade selection”), Levinton (2001), and the exchange between Alroy
and McShea in Paleobiology (2000), vol. 26, pp. 319–33. As to evidence, in the text
of this chapter I concentrated on fossils. This is one of two methods. The other is to
compare the number of modern species between different branches of a phylogeny
with different character states. In Section 22.3.4, we looked at an example in the case
of wind versus biotic pollination. Another example, that fits with a recurrent theme in
this edition, is in Arnqvist et al. (2000). Polyandrous insect clades have a four times
higher rate of speciation than sister monandrous clades. Sexual conflict, of the type we
met in Section 12.4.7, is the prime suspect, and fits with ideas about speciation in
Section 14.12.
On global species diversity, a further topic is how diversity recovers after mass
extinctions. Miller (1998) includes discussion and references. Kirchner (2002) shows
that the speciation rate can have an upper limit that delays recovery following massive
extinctions. The trend to increasing diversity is one of a number of possible
macrotrends in the history of life, a topic reviewed by McShea (1998).
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