[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Declining pterosaur diversity




On Sun, 28 Nov 2004, Jaime A. Headden wrote:

> John Bois (jbois@umd5.umd.edu) wrote:
>
> <Penny, D. and M.J. Phillips 2004 The Rise of birds and mammals: are
> microevolutionary processes sufficient for macroevolution? _Trends in
> Ecology and Evolution_ Vol.19 No.10 pp.518-522.

>   Why does half the paragraph have to be about crown groups and wether or
> not we can refer fossils to them?

Alroy's thing is that nothing important happened until the K/T event;
that this lead to a subsequent radiation of mammals that have the signal
traits of extant mammals.  Crown groups are important to Alroy, no? And
what about me?  I would like a finding of mammals (and birds) that
increase predation/competition pressure over the Cretaceous.  Crown groups
would ne nice but not necessary.

> ...the authors support
> the declining diversity they see as evidence for this replacement regime.
> We need more evidence for this, not ghost competitors to explain a problem
> with the extinction scenario.

One of the most important functions of a scientist is to propose testable
and alternate hypotheses.  This paper is very much in this spirit.