A new study looking at the structure of feathers in bird-like dinosaurs has shed light on one of nature's most remarkable inventions – how flight might have evolved.
Academics at the Universities of Bristol, Yale and Calgary have shown that prehistoric birds had a much more primitive version of the wings we see today, with rigid layers of feathers acting as simple airfoils for gliding.
Close examination of the earliest theropod dinosaurs suggests that feathers were initially developed for insulation, arranged in multiple layers to preserve heat, before their shape evolved for display and camouflage.
As evolution changed the configuration of the feathers, their important role in the aerodynamics and mechanics of flight became more apparent.
Natural selection over millions of years ultimately modified dinosaurs' forelimbs into highly-efficient, feathered wings that could rapidly change its span, shape and area – a key innovation that allowed dinosaurs to rule the skies.
This basic wing configuration has remained more or less the same for the past 130 million years, with bird wings having a layer of long, asymmetrical flight feathers with short covert feathers on top. They are able to separate and rotate these flight feathers to gain height, change direction and even hover.
This formation allows birds to move in such a way as to produce both lift and thrust simultaneously – a capability that man, with the help of technology, is still trying to successfully imitate.
The research, published today [21 November] in Current Biology, looked at the dinosaur Anchiornis huxleyi and the Jurassic bird Archaeopteryx lithographica. The latter is 155 million years old and widely considered to be the earliest known bird, presenting a combination of dinosaur and bird characteristics.
Their wings differed from modern day birds in being composed of multiple layers of long feathers, appearing to represent early experiments in the evolution of the wing.
Although individual feathers were relatively weak due to slender feather shafts, the layering of these wing feathers is likely to have produced a strong airfoil.
The inability to separate feathers suggests that taking off and flying at low speeds may have been limited, meaning that wings were primarily used in high-speed gliding or flapping flight.
Dr Jakob Vinther, from the University of Bristol's Schools of Biological and Earth Sciences, said: "We are starting to get an intricate picture of how feathers and birds evolved from within the dinosaurs. We now seem to see that feathers evolved initially for insulation. Later in evolution, more complex vaned or pinnate feathers evolved for display.
"These display feathers turned out to be excellent membranes that could have been utilised for aerial locomotion, which only very late in bird evolution became what we consider flapping flight. This new research is shedding light not just on how birds came to fly, but more specifically on how feathers came to be the way they are today - one of the most amazing and highly specialised structures in nature."
Dr Nicholas Longrich of Yale University added: "By studying fossils carefully, we are now able to start piecing together how the wing evolved. Before, it seemed that we had more or less modern wings from the Jurassic onwards. Now it's clear that early birds were more primitive and represented transitional forms linking birds to dinosaurs. We can see the wing slowly becoming more advanced as we move from Anchiornis, to Archaeopteryx, to later birds."
University of Bristol: http://www.bristol.ac.uk
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
Dinosaurs, those bygone masters of the planet, were warm-blooded just like today's mammals, according to a scientist who judged their metabolism using body mass and growth rates deduced from fossils of species including Tyrannosaurus rex.
Previously unknown prehistoric beaver bears an uncanny likeness to the modern state symbol
The latest research shows memories “lost” to amnesia aren’t gone forever; they’re just not accessible
The chief disease agency in the U.S. is looking into why the spores shipped to laboratories in nine states and a military base in South Korea hadn't been properly neutralized. So far no one is sick.
When players can change tactics, the game loops endlessly between the three weapons
When you spend five years watching kangaroos, you start to see some strange things.
Nearly three-quarters of fresh shop-bought chickens test positive for food poisoning bug campylobacter in year-long study.
Designed to give paralysed people more independence, the implant also lets us see if brain activity can show a person's decisions – before they realise they've made any
Australopithecus deyiremeda, which lived about 3.4 million yeas ago, suggests our ancestors were more diverse than we thought
Scientists say it's not just a murder from another era, but also part of one of the earliest mass graves.