[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
RE: Dinosaur Revolution Review
> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]
> On Behalf Of Scott Hartman
> Sent: Thursday, September 15, 2011 12:55 PM
> To: Jura
> Cc: dinosaur@usc.edu
> Subject: Re: Dinosaur Revolution Review
>
> I've often disagreed with how Jason applies some of the
> evo-devo findings to feather distribution, but I want to go
> on the record as agreeing with him in part: there really
> isn't a known mechanism for dermal types to shift after
> ovo/utero within an individual's lifetime.
> That's not to say I don't believe in the possibility of
> fuzzy juveniles, but they would have to work within known
> developmental mechanisms.
[snipped a lot of good stuff: go back to the original to read]
It think the error here is the appropriate level at which to look at the
"feathers-back-to-scale" issue. Almost certainly it is
impossible to "go back" **at the follicle level**: once a follicle is dedicated
to one of those modes, it is probably dedicate for
life (or simply turns off).
But we are dealiing with organisms here that in some cases increase their
surface areas by many many many many orders of magnitude,
while scale size (for instance) increases at no where near that rate. Almost
certainly there was the appearance of new follicles
during ontogeny: the developmental process in these has (so far as I know) not
been explored in great detail.
Thomas R. Holtz, Jr.
Email: tholtz@umd.edu Phone: 301-405-4084
Office: Centreville 1216
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661
Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843
Mailing Address: Thomas R. Holtz, Jr.
Department of Geology
Building 237, Room 1117
University of Maryland
College Park, MD 20742 USA