Monday, May 17, 2010

Birds of a Feather

After a brief hiatus, in which I was sunburned beyond all recognition (UV rays bad), its back to the sciencey goodness. I figured I would lead off with a story about feather evolution, and if you've been reading this blog then you know that I just love a good feather evolution story. This one was reported on the ScienceNOW website.

It is generally agreed that birds evolved from small dinosaurs about 150 million years ago. As you may already know, the first birds weren't exactly the best fliers. There has been a debate on about how the feathers of these early birds/later dinos were actually used - for gliding or for more sustained flight.

Robert Nudds of the University of Manchester and Gareth Dyke of University College Dublin took a close look at a 100 million year old bird by the name of Confuciusornis. They were looking to see whether or not the feathers of this bird were strong enough to provide both lift and withstand breaking due to rapid flapping of the arms/wings.

They applied Euler-Bernoulli beam theory (or Engineer's beam theory) to this feathery conundrum. This theory is used by engineers to calculate the load bearing strength of structural beams. The thoery was tested out on the bird's primary feathers (outer edge of wing - the big ones) because they bear the most load. After taking lots of measurements of the feathers (diameters, lengths, etc) and combining it with the estimated body weight of the bird, they plugged the values into the Euler-Bernoulli equations. The conclusion: The wings would have buckled under the stress. The same analysis was performed on the older (140 mya) Archaeopteryx. It also failed.

Other scientists are not completely sold on these conclusions. They cite examples of fossils found in lake and marine sediments, saying that some flight (rather than simple gliding) took the birds to those distances. Also, fossilized feathers can be difficult to measure accurately which could affect the results of the calculations.

The story link:
http://news.sciencemag.org/sciencenow/2010/05/did-first-feathers-prevent-early.html

(image from http://www.toyen.uio.no/palmus/galleri/montre/english/161_632.htm)
Post a Comment
Related Posts with Thumbnails