Navigation Links
Protowings may have helped bird ancestors cover rough terrain

Biologists have long argued about how birds evolved the ability to fly, because it is not immediately evident what improvement in fitness would result from ancestral, partly evolved wings. Two theories have recently dominated the debate: one postulates that flight evolved in tree-dwelling ancestors that used their forelimbs to help them glide, while the other considers ancestral birds to be terrestrial dinosaurs that developed powered flight from the ground up.

An article by Kenneth P. Dial and two co-authors in the May 2006 issue of BioScience summarizes experimental evidence indicating that ancestral protobirds incapable of flight could have used their protowings to improve hindlimb traction and thus better navigate steep slopes and obstructions. By using their protowings in this way, they would presumably have had an advantage when pursuing prey and escaping from predators.

Dial and colleagues performed experiments on several species of juvenile galliform (chicken-like) birds, concentrating on chukar partridges. Chukars can run 12 hours after hatching, but they cannot fly until they are about a week old. Even before they are able to fly, however, the birds flap their developing wings in a characteristic way while running, which improves their ability to climb steep slopes and even vertical surfaces. Dial and colleagues have named this form of locomotion "wing-assisted Iincline running" (WAIR). After they are able to fly, chukars often use WAIR in preference to flying to gain elevated terrain, and exhausted birds always resort to WAIR.

Dial and colleagues describe experiments showing that if the surface area of chukar wings is reduced by plucking or trimming the feathers, WAIR becomes less effective for climbing slopes. Dial and colleagues propose that incipiently feathered forelimbs of bipedal protobirds may have provided the same advantages for incline running as have now been demonstrated in living juvenile birds. Their work thus support s a new theory about the evolution of flight in birds. WAIR, which the authors believe to be widespread in birds, appears to offer an answer to the question first posed by St. George Jackson Mivart in 1871: "What use is half a wing?"


Source:American Institute of Biological Sciences

Related biology news :

1. Invasive exotic plants helped by natural enemies
2. Fused nasal bones helped tyrannosaurids dismember prey
3. Retrovirus struck ancestors of chimpanzees and gorillas millions of years ago, but did not affect ancestral humans
4. New technology shows our ancestors ate…everything!
5. Why we give: New study finds evidence of generosity among our early human ancestors
6. Mans earliest direct ancestors looked more apelike than previously believed
7. UAB scientists discover the origin of a mysterious physical force
8. Researchers discover way to make cells in the eye sensitive to light
9. Protein discovery could unlock the secret to better TB treatment
10. Mouse brain cells rapidly recover after Alzheimers plaques are cleared
11. Newly-discovered class of genes determines ?and restricts ?stem cell fate
Post Your Comments:

(Date:11/19/2015)... 2015  Although some 350 companies are actively involved ... few companies, according to Kalorama Information. These include Roche Diagnostics, ... market share of the 6.1 billion-dollar molecular testing market, ... for Molecular Diagnostic s .    ... controlled by one company and only a handful of ...
(Date:11/18/2015)... 2015 --> ... market report titled  Gesture Recognition Market - Global Industry ... 2021. According to the report, the global gesture recognition market was valued ... reach US$29.1 bn by 2021, at a CAGR of ... America dominated the global gesture recognition market ...
(Date:11/17/2015)... 17, 2015 Paris ... --> Paris , qui s,est ... DERMALOG, le leader de l,innovation biométrique, a inventé le ... et empreintes sur la même surface de balayage. Jusqu,ici, ... l,autre pour les empreintes digitales. Désormais, un seul scanner ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... QUEBEC CITY , Nov. 24, 2015 /PRNewswire/ - ... the request of IIROC on behalf of the Toronto ... this news release there are no corporate developments that ... price. --> --> ... --> . --> Aeterna Zentaris ...
(Date:11/24/2015)... SHPG ) announced today that Jeff ... 27 th Annual Healthcare Conference in New York ... a.m. EST (1:30 p.m. GMT). --> SHPG ) announced ... in the Piper Jaffray 27 th Annual Healthcare Conference in ... 1, 2015, at 8:30 a.m. EST (1:30 p.m. GMT). --> ...
(Date:11/24/2015)... ... November 24, 2015 , ... In ... paramount. Insertion points for in-line sensors can represent a weak spot where leaking ... 781/784 series of retractable sensor housings , which are designed to tolerate extreme ...
(Date:11/24/2015)... , Nov. 24, 2015 HemoShear Therapeutics, ... discovering drugs for metabolic disorders, announced today the ... its Board of Directors (BOD). Mr. Watkins is ... Human Genome Sciences (HGS), and also served as ... Jim Powers , Chairman and CEO of ...
Breaking Biology Technology: