Posted on 06/15/2009 6:27:50 AM PDT by SunkenCiv
Here, we look at a rather different proposal: the decidedly non-standard, non-mainstream Birds Come First (or BCF) hypothesis proposed by George Olshevsky. Rightly or wrongly, BCF has never been discussed in the technical literature (I have at least alluded to it in historiographical articles (Naish 2000a, b)), and all of George's articles on it have been in the 'grey' or popular literature (Olshevsky 1991, 1994, 2001a, b). Thanks, predominantly, to his activity on the dinosaur mailing list (a popular discussion list for dinosaur aficionados and researchers), George's BCF hypothesis was once well known and much discussed, and perhaps considered seriously by at least a few specialists [image below shows some of the 'dino-birds' integral to the BCF hypothesis (read on), with Archaeopteryx at far right. This illustration is (c) Luis Rey and originally appeared in Olshevsky (1994)]
(Excerpt) Read more at scienceblogs.com ...
Birds Come First -- oh no they don't!To begin with, let me note that the underlying premise of BCF is fundamentally problematical: the idea that there is some sort of 'central trunk' (Olshevsky 1994, p. 42) or single, unbroken lineage that extended from the first stem-archosaur to the most recently evolved, modern bird. Old 'family tree' diagrams did indeed show a single, central lineage that included the ancestors of the various 'branches' -- this is where we get the erroneous idea of ladder-like progression and missing links from -- but this concept is erroneous and always relies on the idea that one group or species is somehow special, or sat at the 'top' of the tree (in most trees that 'special' organism is Homo sapiens).
by Darren Naish
Tetrapod Zoology
June 10, 2009
Discovery raises new doubts about dinosaur-bird linksIt's been known for decades that the femur, or thigh bone in birds is largely fixed and makes birds into "knee runners," unlike virtually all other land animals, the OSU experts say. What was just discovered, however, is that it's this fixed position of bird bones and musculature that keeps their air-sac lung from collapsing when the bird inhales. Warm-blooded birds need about 20 times more oxygen than cold-blooded reptiles, and have evolved a unique lung structure that allows for a high rate of gas exchange and high activity level. Their unusual thigh complex is what helps support the lung and prevent its collapse... However, every other animal that has walked on land, the scientists said, has a moveable thigh bone that is involved in their motion -- including humans, elephants, dogs, lizards and -- in the ancient past -- dinosaurs... "For one thing, birds are found earlier in the fossil record than the dinosaurs..." Ruben said... "But one of the primary reasons many scientists kept pointing to birds as having descended from dinosaurs was similarities in their lungs," Ruben said... The newest findings, the researchers said, are more consistent with birds having evolved separately from dinosaurs and developing their own unique characteristics, including feathers, wings and a unique lung and locomotion system. There are some similarities between birds and dinosaurs, and it is possible, they said, that birds and dinosaurs may have shared a common ancestor, such as the small, reptilian "thecodonts," which may then have evolved on separate evolutionary paths into birds, crocodiles and dinosaurs. The lung structure and physiology of crocodiles, in fact, is much more similar to dinosaurs than it is to birds... old theories die hard, Ruben said...
News and Communication Services
Oregon State University
6-9-09
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Gods |
Sometime in the 1990s, the hypothesis was written about in popular mags, such as the Discover article I remember (it's probably around the house somewhere). |
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· Discover · Nat Geographic · Texas AM Anthro News · Yahoo Anthro & Archaeo · Google · · The Archaeology Channel · Excerpt, or Link only? · cgk's list of ping lists · |
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Dinosaur-Bird Flap Ruffles Feathers
Yahoo!News | October 10, 2005 | E.J. Mundell
Posted on 10/11/2005 4:07:11 AM PDT by mlc9852
http://www.freerepublic.com/focus/news/1500340/posts
Surprise: Chickens Can Grow Teeth
Live Science | 22 February 2006 | Bjorn Carey
Posted on 02/23/2006 6:41:48 AM PST by GreenFreeper
http://www.freerepublic.com/focus/news/1584077/posts
[snip] ...a mutant chicken with a full set of crocodile-like chompers... called Talpid, also had severe limb defects and died before hatching. [end]
Cretaceous Chicken: Bus-Sized Dinosaur Breathed Like Birds Do
foxnews | September 30, 2008
Posted on 09/30/2008 3:08:33 PM PDT by Justice Department
http://www.freerepublic.com/focus/chat/2094323/posts
Downy dinosaur found in China was an early bird
The Times | 1/13/2008 | Lewis Smith
Posted on 01/12/2009 6:55:59 PM PST by bruinbirdman
http://www.freerepublic.com/focus/news/2163538/posts
BCF is not BADD.
:’)
Well, it’s about time “science” got it right: Genesis very properly said birds were created very shortly after the “monsters in the sea.”
And both critters were said to be around a long time before any of the modern mammals.
The only way to solve these questions is to invent a time machine. /sarc
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