Link:INB Home|INB English| INB русский язык|INB العربية|INB Türkiye|INB فارسی|INB Español|INB Français|INB Português|INB Deutsch|INB 國語|INB 中文|INB 日本语|INB 한국어|INB ภาษาไทย|INB tiếng Việt||Dinosaurs Jurassic Heavier Dino Arms Led Evolution To Birds
INB English forum
Welcome to (Industry & Native boffin) The industrial age here is full of fighting spirit, you and I both through this network space with Native biological spirit boffin came to the mad labs. home INBforum.com, come and join us Permanent name: inb-english.forumotion.com
INB English forum

Welcome to (Industry & Native boffin) The industrial age here is full of fighting spirit, you and I both through this network space with Native biological spirit boffin came to the mad labs. home INBforum.com, Permanent name: inb-english.forumotion.com


You are not connected. Please login or register

《《《《《《《上一页INBforum   Go down

上一页INBforum》》》》》》》View previous topic View next topic Go down  Message [Page 1 of 1]

1 Dinosaurs Jurassic Heavier Dino Arms Led Evolution To Birds on Sun Oct 12, 2014 12:45 am

Admin


Admin

 VIEW RELATED GALLERY »
Maniraptoran dinosaurs, such as Velociraptor, which were in the lineage that evolved into birds, dramatically developed a crouching trait.
SERGEY KRASOVSKIY/STOCKTREK IMAGES/GETTY IMAGES

 GALLERY
DinosaursofaFeatherComeTogether:Photos
VIEW CAPTION + 
VIEW CAPTION + 
VIEW CAPTION + 
VIEW CAPTION + 
VIEW CAPTION + 
VIEW CAPTION + 
VIEW CAPTION + 
VIEW CAPTION + 

UP NEXT
Meet The Top 10 Meat-Eating Dinos: Photos
[size=100]‹[/size]
[size=100]›[/size]
RELATED links
PHOTOS: Dinosaur Feathers Found In Amber
Birds Descended From Gliding Dinosaurs
Oldest Bird Was Actually A Dinosaur
 

Many dinosaurs, like T. rex, had scrawny arms, but paleontologists have discovered that as dinosaurs gradually evolved bigger arms, they began to stand and move more like birds.
The change, documented in the journal Nature, passed on to the descendants of dinosaurs -- birds themselves.
"Our study shows how mass was allocated to the forelimbs, starting in non-flying dinosaurs, to turn them into longer, heavier, more muscular wings that became more and more effective for flapping during flight," co-author John Hutchinson of the Royal Veterinary College’s Structure and Motion Lab told Discovery News.

PHOTOS: Dinosaurs of a Feather Come Together


Hutchinson and his colleagues used digitizing technology to create 3D images of the skeletons of 17 archosaurs, a group that included living crocodiles and birds as well as extinct dinosaurs. The researchers then digitally added flesh around the skeletons to estimate the overall shape of the body as well as the individual body parts, such as the head, forelimbs and tail.
The scientists found that as the arms got bigger, eventually turning into wings in some species, the hind limb posture got progressively more crouched as the center of mass moved forward. Before then, dinosaurs that stood on two legs had a fairly straight posture, similar to that of humans. Maniraptoran dinosaurs, such asVelociraptor, which were in the lineage that evolved into birds, dramatically developed this crouching trait.
Posture varies among today’s birds, with larger species like ostriches tending to have straighter legs to more economically support their own weight. But even these birds still have fairly crouched limbs overall.
The discovery calls into question an earlier theory that held dinosaurs became more bird-like when their tails grew shorter and lighter. Hutchinson and his team acknowledge that happened, but only after the other changes took place.
He explained that "the shortening of the tail coincided with a reduction of a once-large tail muscle that connected to the thigh and moved the leg back and forth during locomotion. Birds only have a tiny remnant of that muscle."
]

View user profile http://eng.inbforum.com

上一页INBforum   Go down

上一页INBforumView previous topic View next topic Back to top  Message [Page 1 of 1]

Permissions in this forum:
You cannot reply to topics in this forum

Copyright ©2009-2016 LTD Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

IT:SINGLESERVGoogle谷歌翻译TranslateFORUMSOFTLAYERGoogle谷歌广告联盟AdSenseAsia

 

Free forum | © PunBB | Free forum support | Contact | Report an abuse | Free forum