By CARL ZIMMER - NATIONALGEOGRAPHIC.COM
Added: Thu, 03 Feb 2011 13:39:01 UTC
Thanks to Alan for the link. original link
Most of us will never get to see nature's greatest marvels in person. We won't get a glimpse of a colossal squid's eye, as big as a basketball. The closest we'll get to a narwhal's unicornlike tusk is a photograph. But there is one natural wonder that just about all of us can see, simply by stepping outside: dinosaurs using their feathers to fly.
Birds are so common, even in the most paved-over places on Earth, that it's easy to take for granted both their dinosaur heritage and the ingenious plumage that keeps them aloft. To withstand the force of the oncoming air, a flight feather is shaped asymmetrically, the leading edge thin and stiff, the trailing edge long and flexible. To generate lift, a bird has merely to tilt its wings, adjusting the flow of air below and above them.
Airplane wings exploit some of the same aerodynamic tricks. But a bird wing is vastly more sophisticated than anything composed of sheet metal and rivets. From a central feather shaft extends a series of slender barbs, each sprouting smaller barbules, like branches from a bough, lined with tiny hooks. When these grasp on to the hooklets of neighboring barbules, they create a structural network that's featherlight but remarkably strong. When a bird preens its feathers to clean them, the barbs effortlessly separate, then slip back into place.
The origin of this wonderful mechanism is one of evolution's most durable mysteries. In 1861, just two years after Darwin published Origin of Species, quarry workers in Germany unearthed spectacular fossils of a crow-size bird, dubbed Archaeopteryx, that lived about 150 million years ago. It had feathers and other traits of living birds but also vestiges of a reptilian past, such as teeth in its mouth, claws on its wings, and a long, bony tail. Like fossils of whales with legs, Archaeopteryx seemed to capture a moment in a critical evolutionary metamorphosis. "It is a grand case for me," Darwin confided to a friend.
Stephen Cave - Financial Times Comments
What we really know about our evolutionary past – and what we don’t
- - Ancestors Trail Walk Comments
WALK DARWIN’S TREE OF LIFE ~ 26 AUGUST 2012 - event begins on Saturday 25 August
Liat Clark - Wired.co.uk Comments
Astrophysicists simulate 14 billion years of cosmic evolution in high resolution
Alok Jha - The Guardian Comments
Cambridge scientists claim DNA overlap between Neanderthals and modern humans is a remnant of a common ancestor
- - Science Blog Comments
Why, after millions of years of evolution, do organisms build structures that seemingly serve no purpose?
Charles Choi - CBS News Comments
Four decades ago, in 1972, the Koobi Fora Research Project discovered the enigmatic fossilized skull known as KNM-ER 1470 which ignited a now long-standing debate about how many different species of early Homos existed.
MORE BY CARL ZIMMER
Carl Zimmer - Discover Magazine Blogs Comments
There’s something fascinating about our chromosomes. We have 23 pairs. Chimpanzees and gorillas, our closest living relatives, have 24. If you come to these facts cold, you might think this represented an existential crisis for evolutionary biologists.
Carl Zimmer - iTunes Comments
Science writer Carl Zimmer and evolutionary biologist Douglas Emlen have teamed up to write a textbook intended for biology majors - free app available for the iPad
Carl Zimmer - Discover Magazine Blogs 13 Comments
The human genome contains about 100,000 fragments of endogenous retroviruses, making up about eight percent of all our DNA
Carl Zimmer - The New York Times 19 Comments
The first goal of the project, known as the Open Tree of Life, is to publish a draft by August 2013. For their raw material, the scientists will grab tens of thousands of evolutionary trees that are archived online. They will then graft the smaller trees into a single big one.
Carl Zimmer - The Loom 6 Comments
A Hot Young Earth: My Answer to the
Annual Edge Question