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Re: Extinction once again (was Re: ARE ORNITHOPODS BORING?)


To what Dan is saying, I would only reiterate what has been said before. The preponderance of evidence points to a quick and massive extinction, and even many surviving groups (like birds) suffered huge losses.
Therefore I personally think it is much easier to discuss the reasons the survivors made it through, and not dwell on those which didn't make it through K-T, which died from a multitude of factors which we could endlessly speculate about and never reach a consensus. If the blast didn't get them directly, there were plenty of after effects (injury, disease, asphyxiation, starvation, hypothermia, and so on). Nesting habitat problems may have been the "straw" that killed off some surviving species, but probably insignificant considering everything else that was going on.
To put it any other way, look at the glass as 1/4 full, and not dwell on the 3/4 that is empty. The more I learn about massive extinctions, the more convinced I am that this a more productive approach.
My two cents worth, Ken
****************************************************** 
From: Danvarner@aol.com
Reply-To: Danvarner@aol.com
To: dinosaur@usc.edu
Subject: Re: Extinction once again (was Re: ARE ORNITHOPODS BORING?)
Date: Sat, 17 Feb 2001 11:55:48 EST

In a message dated 2/17/01 7:46:16 AM Pacific Standard Time,
jbois@umd5.umd.edu writes:

<< ...adding stress to species which nested on the shores of the "Oceans of
Kansas." Habitat loss is the main cause of today's extinctions--why
would we doubt that it was important in other times--especially when we
know that vast tracts of potential nesting territory were reduced to zero? >>

This is pure speculation, but I would assume, that as in the present,
waterfowl of the K probably took advantage of the high productivity of the
long days of the upper latitudes during the nesting season. Productive
nesting areas today are places like the Yukon delta. Deltas wouldn't have
been effected that much by regressions unless the strandlines approached the
edge of the continental shelf. Remember also that the Western Interior
Seaway turned into one huge delta in the latest K. I see nesting real estate
for waterbirds actually increasing.
Focusing on the "Oceans of Kansas" for models of the K/T extinction Is
using way too small of an area for a sample in my opinion. What would have
been happening in Antarctica during the final K regression, for instance? DV. 
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