[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
The actual running Archie paper...
...is in this week's Nature. (Nature 399: 60 - 62).
Haven't seen the article yet, but from the Nature website, here is the
abstract (aka first paragraph):
The wing of Archaeopteryx as a primary thrust generator
PHILLIP BURGERS AND LUIS M. CHIAPPE
Since the late 1800s, the debate on the origin of flight in birds has centred
around two antagonistic theories: the arboreal (take-off from trees) and
cursorial (take-off from running) models. Despite broad acceptance of the
idea that birds evolved from bipedal and predominantly terrestrial
maniraptoriform dinosaurs, the cursorial model of flight origins has been less
successful than the arboreal model. Three issues have contributed to this
lack of success: the gap between the estimated maximum running speed of
Archaeopteryx (2 metres per second) and its estimated minimum flying
speed (6 metres per second); the high energy demands of evolving flight
against gravity; and the problem of explaining the origin of the 'flight' stroke
in an earthbound organism. Here we analyse the take-off run of
Archaeopteryx through lift-off from an aerodynamic perspective, and
emphasize the importance of combining functional and aerodynamic
considerations with those of phylogeny. Our calculations provide a solution to
the 'velocity gap' problem and shed light on how a running Archaeopteryx
(or its cursorial maniraptoriform ancestors) could have achieved the velocity
necessary to become airborne by flapping feathered wings.
So, they ARE addressing the phylogeny question to a certain degree (although
to what degree has yet to be determined). Note also that in the abstract at
least they say that it *could* provide a solution and shed light on a
ground-up scenario, not that it demonstrates unequivocally that "ground-up"
Still, I will play by my own rules and wait to see the data before going any
Thomas R. Holtz, Jr.
Vertebrate Paleontologist Webpage: http://www.geol.umd.edu
Dept. of Geology Email:firstname.lastname@example.org
University of Maryland Phone:301-405-4084
College Park, MD 20742 Fax: 301-314-9661