Amazing but true coincidence at K/T.

[John Bois <jbois@umd5.umd.edu>]

You could argue that post K/T evolution of mammals and birds was
simply crossing the "t"s and dotting the "i"s.  The major work
had already been done: for mammals, a reason had been found for
cognitive development and some adaptive threshold had been
reached which made further development likely, and reproductive
modes had been made secure; for birds, flying had been
"perfected", and, in part because of this, they were
reproductively secure as well.  In a sense, as subsequent
evolution bore out, mammals and birds had come of age at the K/T!

Explaining mammalian evolution in terms of them being simple
beneficiaries of "ecological release", i.e., as merely moving
into the niches left vacant by the dinosaurs is, in light of what
they had already evolved at that time, insufficient.  Relative to
their reptile forbears, they had made some profound advances
requiring major genetic innovations.  Now, this culmination of
two separate phylogenies to a point where they could both take on
the world, at just the same time--at the K/T--is an amazing
coincidence!!!!  BUT IT HAPPENED!  So here we are looking for a
non-amazing cause (bolide) for all the species' perturbations at
the K/T (terrestrial, at least) when we have a perfectly
legitimate _amazing_ cause, the coincidence of the coming of age
of two major vertebrate lines.

     And you tell me that this would have no significant effect
on the other vertebrates of the day.