Re: Selective Extinction

[Chris Campbell <sankarah@ou.edu>]

Rob Meyerson wrote:
> 
> Betty Cunningham writes,
> 
> >birds, of course, survived, whereas pterasauroids did not so if you can
> >perhaps explain why?
> >Wehn Mt. St. Helens went off, birds that flew away survived, but still
> >had to deal with the ash that covered everything afterwards to search
> >for food and water.
> 
> When we look at the major theories for the late-K mass extinction, all 
>of them point to a heavily restrictive environment.  To use the haymaker-
>impact scenario as an example, the resulting disruption of the land food 
>chain will mean that food will be in short supply.  Because of this, 
>animals that can get by on small amounts of food will survive, which would 
>include most ectotherms and smaller endotherms.  Under this hypothesis, 
>birds survived because they enhabited the "small endotherm" end of the 
>scale, while the pterosaurs were in the "large endotherm" end.
> 
> So, IMHO, birds survived simply because they were small.

Problem being that crocs (large ectotherms) survived while small dinos
(small endotherms) didn't.  

Chris