| Creation & Evolution Forum for the discussion of this important topic. This forum is open to non-believers. There is a Christians-only forum in the Christians-only section too. |
 | | 
25th February 2006, 08:50 PM
| | Junior Member
  
| | Join Date: 25th February 2006
Posts: 19
Blessings: 90,386
Reps: 10 (power: 0) | | | interesting.... |
6th March 2006, 03:21 AM
|  | Soldier of Knowledge
28    
 | | Join Date: 18th January 2004 Location: Ohio
Posts: 1,720
Blessings: 59,514
Reps: 18,604,695,596,698 (power: 18,604,695,606) | | Originally Posted by Oncedeceived No problem, thanks for letting me know.
Well, I never managed to find the PDF of that article. But one of the members of the paleontology forum where I requested it has given me a couple excerpts from it, that describe some of the differences between avian feathers and the structures on Longisquama. Appendage PIN (for Palaeontological Institute of the Russian Academy of Sciences) 2584/7, preserved as part and
counterpart, retains an infilling of finegrained sediment and high-fidelity impressions of the external left and right surfaces
of the appendage (Fig. 1). This infilling, preserved either on one side of the specimen or on the counterpart, shows that the
tubular configuration described for the proximal portion extends along the entire length of the appendage,
although the distal portion is expanded anteroposteriorly and flattened transversely. This indicates that in
life the two external surfaces were separated from each other by an intervening space (now sediment-filled Here, two corrugated membrane-like surfaces touch along their leading and trailing edges to form wide, smooth bands.
The two membranes were apparently supported by a median veinlike structure extending the length of the
appendage. This has been proposed as the homologue of the rhachis of avian feathers2. On either side of this ‘vein’, the external surfaces of the appendage are corrugated.
This corrugation varies along the appendage: proximally, individual rugae are relatively large and widely spaced,
but in the distal portion they are smaller and densely packed. The densely arranged distal corrugations have been compared to the pinnae of avian feathers, but the fossils indicate that these are formed on a membrane-like structure on either side of the ‘vein’.
From Reisz, Sues. 2000.
What this article is basically saying is that the structures on Longisquama had separate front and back membranes, which were subdivided into smaller corrugations. This is different enough from the structure of feathers that it’s unlikely the two could be homologous, although it’s still possible that the structures on Longisquama were developed from the same fiber-like elongation of scales that developed into feathers in dinosaurs.
__________________
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
|
30th April 2006, 11:51 AM
|  | Contributor
65 
| | Join Date: 4th March 2003
Posts: 6,393
Blessings: 117,788 My Mood 
Reps: 19,183,710,574,649,584 (power: 19,183,710,574,664) | | | I thought I would bump this thread because of our current discussion. Aggie's OP and following posts present some excellent evidence for the evolution of birds from dinosaur ancestors.
The Frumious Bandersnatch
__________________
A little Learning is a dang'rous Thing;
Drink deep, or taste not the Pierian Spring:
There shallow Draughts intoxicate the Brain,
And drinking largely sobers us again.
Alexander Pope
|
30th April 2006, 02:28 PM
| | Human
28 
| | Join Date: 13th October 2003 Location: Texas
Posts: 5,593
Blessings: 100,530
Reps: 7,339 (power: 21) | | |
__________________
"If I don't post here... I'll have to go back to writing 6000 words on an anarchist critique of the political philosophy of John Rawls... So it's either this or beer, and beer costs money." -Zoot |
3rd May 2006, 11:53 PM
|  | MokAce - Priest of the Flying Spaghetti Monster
24 
| | Join Date: 2nd January 2006
Posts: 1,528
Blessings: 90,980
Reps: 2,268 (power: 10) | | Originally Posted by Arkanin's Link TEST: If you believe birds evolved larger and larger wings over millions of generations until they could finally fly you are brainwashed.
Ironic indeed. |
4th May 2006, 12:33 AM
| | Senior Member
22 
| | Join Date: 11th April 2006
Posts: 955
Blessings: 91,695
Reps: 3,559 (power: 9) | | Originally Posted by Arkanin
Here's a quick tip: Don't throw your lot in with people who try to prove that fruits and vegetables will kill you. That way lies only suffering.
Suffering and hilarity. |
20th May 2006, 05:42 AM
|  | Senior Veteran
21  
| | Join Date: 9th January 2005 Location: Sydney
Posts: 3,219
Blessings: 2,067,252
Reps: 67,527,722,863,596,368 (power: 67,527,722,863,607) | | For example, this animal’s clavicles had been fused into a furcula (or “wishbone”) because this helped it to hold onto its prey. Unfortunately, I was unable to find a picture of this.
It's amazing how we have such a detailed fossil record. As far as I am aware, Coelophysis are among the first dinosaurs to have a fused clavicle (furcula). Furcula's can also be found in birds today!
Are furculas only found in birds? If so, then therapod dinosaurs can be shown to already have distinguishing avian features! Originally Posted by loony website The bird is said by evolutionists to grow hollow bones for less weight in order to fly. How would a bird pass this long-term plan to the millions of generations in order to keep the lighter bone plan progressing? The idea that birds or anything else has million-generation evolutionary plans is childish.
Of course, evolution isn't actively planned by creatures. They aren't even aware of it happening.
Birds with lighter bones would be more likely to survive than birds with heavier and thick-walled bones, and so this advantageous trait becomes dominant.
Also, it is not only birds that have thin-walled bones. Therapods like Coelophysis, Velociraptors and Archaeopteryx all have lightened bones.
__________________
Credit for avatar art goes to Kate Beaton.
| | |
| Thread Tools | | | | Display Modes |  Linear Mode |
| | |
