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Re: Temperature and Offspring Size

People here at the 45 degree parallel in Vermont are moving toward a
"flipper shape" rapidly--short arms, short legs, round bodies. Heat
conservation measure (surface/volume), obviously, that will be useless when
global warming takes full effect.
Scott Perry
----- Original Message ----- 
From: "Richard W. Travsky" <rtravsky@uwyo.edu>
To: <dinosaur@usc.edu>
Sent: Tuesday, October 03, 2006 3:54 PM
Subject: Temperature and Offspring Size

> Not sure of the implications for dinocritters since all the eggs/newborn
> that I ever read about are small, even for large parents...
> http://www.sciencedaily.com/releases/2006/10/061002214856.htm
> ...
> In a new study from The American Naturalist, Michael Angilletta (Indiana
> State University), Chris Oufiero (University of California, Riverside),
> and Adam Leach (University of California, Berkeley) used a new statistical
> approach that can test multiple theories at the same time, an approach
> they hope will shed light on many evolutionary problems.
> They used data from many populations of Eastern Fence Lizards (Sceloporus
> undulatus), which revealed that the lizards in colder environments produce
> larger offspring than lizards in warmer environments.
> So why do animals in colder climates produce larger offspring? One theory
> suggests the larger size of offspring counteracts their slow growth in the
> cold. Yet another theory suggests large offspring are not directly linked
> to temperature at all. Instead, large offspring just happen to be produced
> by large mothers, who grow large because they require more energy to
> reproduce in the cold.
> When they tested the theories simultaneously with their new approach, the
> team concluded that temperature's effect on reproduction is a byproduct of
> its effect on adult size. "This result could have widespread
> significance," says Angilletta. "Temperature determines the adult size of
> virtually all organisms. For many of these organisms, we expect
> temperature to also leave an imprint on reproduction."
> ...