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RE: How Did Hadrosaurs Survive?



Strange things happen again. Judging from the archives, traffic is so high 
that listproc can't keep up sending me all the e-mails so I haven't even got 
the following yet. I'm answering based on my Sent Mail.

On Thursday, 31. October 2002 20:05, I wrote:

> [...]

> This is part of the reason why the predator is _always_ at a disadvantage.
> Here's what an intro lecture in ecology says:
>
> 1. The life-dinner principle. [...]
>
> 2. The prey is a moving target. [...]

And of course I forgot the third aspect, the Limited Catastrophe model aka 
Survival of the Imperfect:

Anteaters dig termite nests open. They eat for 5 to 10 minutes, stop, clean 
their fur painstakingly and go on to the next nest. Results in a dozen nests 
and 5 to 10 km per night. What for? Why don't they open fewer nests and eat 
them empty? In hindsight it's clear: it's resource management, the anteaters 
keep the nests alive. But how do they know? It turns out that about 5 min 
after a nest has been opened the termite soldiers have reached the anteater's 
skin and bite so the anteater has to stop. Anteater skin is not optimally 
adapted. How come? It can't be a design constraint, vertebrate skin is 
enormously adaptable, close relatives of anteaters like armadillos and, to a 
lesser extent, ground sloths have evolved armor.
        The idea here is that if a mutation occurs that increases fitness 
beyond 
what is sustainable in the long term, it spreads throughout the deme, and the 
deme dies out before more can happen. (Demes, from Greek demos = a people, 
are parts of populations. Organisms in the same population are in 
theoretical, those in the same deme in actual sexual contact.) So any armored 
anteaters have starved long ago. And the simple observation that 
*Tyrannosaurus* survived for millions of years looks like good evidence that 
it wasn't an Ultraraptor (search the archives of 1999 for this term if you 
need it).

In the archives it says "remainder of message truncated". There is no 
remainder, you haven't missed anything. :-)