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Egg predation? The fossils say no!
My apologies to all who have a) had enough of both of the threads I've
responded to today, and b) had enough of sifting through my gargantuan
On mammalian egg predators wiping out dinosaurs:
I'm afraid that this theory has become on of those "just so stories" of
evolution of the type that the media peddles as fact. I am extremely
suspicious, and have grown more than a bit weary, of theories that involve
one species out competing another, and the idea that whole groups can be out
competed (yes, this I am including having all of their eggs eaten) by a whole
other group is bordering on unreasonable.
Yes, there are no simple explanations. I just watched the Discovery
Channel last night tell me that Angiosperms were too tough for Barasaurus to
eat, so _Barasaurus_ died out. They may have been on the right track, but
since, as far as I know, _Barasaurus_ and angiosperms NEVER MET, there seems
to be a problem.
The problem I see here is scale, time and taxonomic. We have a date
after which no non-avian dinosaurs lived. It's called the K/T boundry (yes,
it's a range, but, jeez, at what second where you born, when you head came
out, or when the umbilical was cut?). It is both a geological event, and a
biological marker. Whether or not dinosaurs were on the decline or not
before the end, that was their end. Now you're going to tell me that the
last thirty or so million years of dinosaur evolution was a losing battle
with egg thieves?
Evolution, my friend, works on a much shorter time scale. If a threat
becomes too much for a species to bear, it evolves or dies out. You portray
the constant pressure of milk-sucking furballs grinding down the entire group
of dinosaurs. Well, it wouldn't have. It would have ground down each
species, one at a time. They could not have applied equal pressure to all
dinosaurs so that they all died out on April 1st, 65 million BC. And before
you react to my saying "all", see below.
But, you know, there's something funny here, because, when each species
went extinct, it's niche was NOT filled by those "fabulous furballs" (humbug,
I say). It's niche did not stay vacant (ok, perhaps at the very end, but if
you want to argue that all of this happened in the last million years of dino
evoltuion, see below). A NEW DINOSAUR rose to fill it. And, in order for
that new dinosaur to rise, it had to adapt (that being the name of the game),
to fight off the egg stealers. Now, y'all can argue your egg laying
strategies all you want, but I can tell you one thing, if a new species
evolves in this putatively egg-hostile environment, it *HASU* to be doing
So now we return to the possibility of all of this class warfare
happening in the last million years or so of dinosaur evolution, where,
theoretically, no one has the time to evolve a defense strategy. Competition
breeds evolution. And, all of a sudden, these pesky Ubermammals that are
claimed to be so hot are getting nailed by the proliferation of small
I will not now, nor I suspect will I ever, stipulate to the possibility
of several independant (for it would have to happen on several continents
simulatneously, why would you emigrate when there's *SO* much plentiful food
right there) groups of ovivorous mammals suddenly rising from the earth like
the Rabach from the ocean to devour ALL dinosaurs eggs, and especially to eat
every Troodon, Velociraptor, Deinonychus, etc egg before they could breed
like rabbits on the new food supply.
I will not even stipulate to increased predation weaking dinosaurs for
the final battle, for the above reason (more prey = more predators), and also
because, if dinosaur eggs were such an easy target, then your theory must
assume that 100 million years of evolution had not produced a bird, lizard,
snake, pterodactyle, thecodont, or small dinosaur that would not have already
exploited this niche. Mammals are *NOTHING* special, they are certainly not
God's gift to the earth, and we should not start endowing cretaceous mammals
with supernatural powers in order to provide a just-so story to ease our
minds on the question of the K/T extiction.
Sorry. That may have rambled or sounded accusatory. Didn't mean to go off
that much, but, hey, I'm no SJ Gould.
Jonathan R. Wagner
Graduate student sanz portfolio