Re: "Oxygen Helped Mammals Grow, Study Finds"

[Tim Williams <twilliams_alpha@hotmail.com>]

Mike Taylor wrote:

> On the Internet, no-one knows who you are.  How can you tell that I'm
> not an algae colony with unusually developed typing skills?
>
> (I'm not really an algae colony, of course.  I'm a lobster.)

I'm a slime mold!

David Marjanovic wrote:

> One more quote (refs removed):
> "Whereas the relatively rapid decline in oxygen at the end-Permian and 
> early Triassic is suggested to have been a major factor contributing to the 
> extinction of terrestrial animals (mostly reptiles) at this time, the rise 
> of oxygen over the ensuing 150 My almost certainly contributed to evolution 
> of large animals.

This may be a daft question, but I had heard/read that oxygen levels were 
relatively high during the Permian.  This allowed large flying insects 
(_Meganeura_) to thrive during this period, owing to the higher oxygen 
tension in the atmosphere.  The end-Permian drop in O2 may have contributed 
toward their extinction too.

> Interesting how the authors use "secular" -- apparently for "long-term".

As in "The data presented here provide evidence of a secular increase in 
atmospheric oxygen over the past 205 My that broadly corresponds with three 
main aspects of vertebrate evolution, namely endothermy, placentation, and 
size."

I think we need to know more about the religious beliefs of marsupials 
before we can draw any firm conclusions.

Cheers

Tim