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From: John Bois <email@example.com>
> Where am I going wrong? Using your "data" I made 72 little slips of
> paper and colored 30 green (mammals), 12 red (dinos), 5 pinks, 15 blues,
> 10 yellows. Then I took out 30%--and your 75% extinction rate is
> high. In Ward's Nov. _Science_ paper 70% is cited so I used that--or 22
> slips at random. I simulated 10 K/T extinctions. Only one <clade> became
> extinct (Yellow) and that only happened once!!!
If I remember right, the _Science_ paper had a 70% *extinction* rate,
not a 70% survival rate. Certainly a 30% species extinction rate
is way low, as the *family* extinction rate is almost that high, and
rates get larger, not smaller, at lower taxonomic levels.
I think this is your problem. At a 30% species extinction rate, few
higher taxa will become extinct, as you found out.
Another way to get the species extinction rate is to *average* the
extinction rates from the various non-protected groups in Archibald's
data. I am fairly certain that this number will come out to be over
50% at the very least.
The peace of God be with you.