The Evolution of Flight
Chapter 13: IMAGES FOR LECTURES
CHAPTER 13: UPDATES
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OCTOBER 2005. NEW THOUGHTS ON PTEROSAUR FLIGHT (p. 169)
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FEBRUARY 2005. Gliding Ants (p. 165)
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New flight model for pterosaurs. Basically, the novelty is in proposing a flap effect for a strip of tissue along the leading edge of the wing, manipulated by the pteroid bone. The idea was tested in a wind tunnel. The "flap" would have been used mainly on take-off and landing, but could have been used to do barrel-rolls in flight (if needed!). This function would be analogous to the flaps on an airplane (aeroplane for Brits). And all pterosaurs had it. The paper was in the Proceedings of the Royal Society of London, October 2005. I think it is a classic. The experiments were done in Ellington's lab in Cambridge, so you can be sure about them. What they have done is to take away any lingering doubt there may have been that pterosaurs could take off and land effectively.
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Gliding ants. Here's something else to add to the list of animals that have evolved gliding. Press release from UC Berkeley, February 2005. Astounding: but there are probably lots more of them if anyone looked.
CHAPTER 13: NOTES AND WEB LINKS
Flight in Insects
P. 166. Swimming (and skimming) as a preadaptation
Flight in Vertebrates
UC Berkeley's pages on vertebrate flight: the subsections include pages on most of the sections below.
P. 167. Parachuting Vertebrates
P. 167. Early Gliding Vertebrates
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Sharovipteryx, a Late Triassic gliding lepidosaur
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Longisquama, a Late Triassic gliding lepidosaur
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Longisquama, including a photograph of the real specimen.
Pterosaurs
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Introduction to Pterosaurs from UC Berkeley
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Pterosaurian flight from the UC Berkeley site: you can bet that Kevin Padian had a lot of input into this one!
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Masters of an Ancient Sky: feature article from 1994 in Discover magazine. Excellent survey of the state of research into pterosaur flight at that time. Discover magazine
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Lords of the Ancient Skies: a feature article from National Geographic. National Geographic
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A new pterosaur (from the Cretaceous of Brazil), claimed to fish by skimming the water.
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The largest pterosaurs: azhdarchids. These include Quetzalcoatlus, perhaps best interpreted as a gigantic heron, fishing in inland lakes, or striding on and around wetlands looking for crayfish from shallow water, or for frogs or turtles. The best popular account of this is by Darren Naish on his blog: Tetrapod zoology blog, with many links, including one to the serious paper on azhdarchid palebiology, which they published in the open-access PLoS One.
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The brilliant paper by Larry Witmer and colleagues on pterosaur brains, balance, and behavior, published October 2003:
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Pterosaur nests have been found occasionally, but a major nesting area has been discovered in Chile.
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A pterosaur embryo inside a pterosaur egg. Illustration from a Nature paper, 2004.
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The full Nature paper
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Pterosaur crests as display structures. BBC News OnLine, July 27, 2006. The paper is in Palaeontology.
Birds
Birds are much underrated in terms of intelligence: "bird-brain" is a term of abuse in American vernacular. The reality is that (modern) birds are very clever, and it may be that the cunning of dinosaurs was one of things that Michael Crichton got right in Jurassic Park:. Crows have been studied intensively:
The Solnhofen Limestone
Home of Archaeopteryx, the earliest bird, and many beautiful pterosaur fossils.
Early Birds, including Archaeopteryx
The Origin of Feathers
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How feathers form in chickens.Press release, October 31, 2002. The hope is (and it is only a hope) that the sequence seen in chickens is also the evolutionary sequence that took place 150 million years ago. Not guaranteed!
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Many theropod dinosaurs had feathers. That means that feathers did not evolve for flight. So how/why did they evolve? I naturally like an idea that I developed jointly with my colleague Jere Lipps. Here, for historical interest, is what Jere Lipps and I wrote in 1982.
The Origin of Powered Flight in Birds
The Display and Fighting Hypothesis
The WAIR hypothesis
was published in January 2003. .pdf file of the paper
Here's my take. The observations on living birds are fascinating, but the application to the origin of bird flight is wrong, in my opinion. I wrote a very brief note to Science about it, but it was not published: Letter to Science, submitted February 2003, rejected March 2003.
Did Archaeopteryx Fly?
It is fair to say that opinion is divided on whether Archaeopteryx could fly. . (Long essay on Wikipedia, updated to March 2013.)
I suspect that Archaeopteryx could not fly. Part of the problem as I see it, and say in the book, is that Archaeopteryx could not have had an effective upstroke without the supracoracoideus system. For my longer mini-essay on the lack of flight in Archaeopteryx, see this mini-essay.
In 2010, Nudds and Dyke reported in Science that the feathers of Archaeopteryx were too weak to support active flight. Abstract of the paper
Phil Currie argued in response that since Archaeopteryx was preserved in shallow marine sediment, that it must have flown to get there. This is nonsense: Schäfer's 1972 book on paleoecology from the 1970s described in detail how dead shorebirds floated out to sea after drying out on the beach. ScienceNow news item.
In May 1999, Nature published a paper by Burgers and Chiappe, which claimed that Archaeopteryx ran well, and was able to take off by flapping its wings and running. I have problems with this paper. In a nutshell, I suspect that Burgers used equations from living birds that fly to do his calculations on Archaeopteryx. In other words, he assumed his answer first. But he avoids saying that, even in the small print of the footnotes... Here is the paper, rightly or wrongly posted on the Web, but not by Nature.
New Cretaceous Birds
Some Cretaceous birds and close relatives:
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Jeholornis, a new primitive fossil bird from China, with seeds preserved in its gut.
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Feature on the fossil deposits of Liaoning, China, from BBC News OnLine.
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Confuciusornis, an Early Cretaceous bird from China. (It has DISPLAY feathers!).
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Protopteryx, a new very early bird from China.
Description with images.
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A feathered bird chick from the Lower Cretaceous of China. It is tucked up as if it died inside the egg at a very late stage, and it's strong-boned and feathered. If it's feathered at this stage, it would have hatched as a precocial chick. That means (to me) that the bird was NOT nesting in a tree, but on the ground. Yet the artist, Zongda Zhang, has portrayed the birds as hatching in a nest in a tree! I can't think of a precocial chick today that hatches from a nest in a tree. Maybe there's some inscrutable logic that requires (maybe even permits) such an interpretation, but I don't see it. The Beijing group working on early birds seem to be fixated on an arboreal origin for flight (so maybe for birds?), and this may be an offshoot of that viewpoint, in the face of the evidence. Or maybe I am biased: I am on record in the book as saying the arboreal origin of flight is nutty (to paraphrase). Anyway, read the blurb, read the paper (which is in Science, October 2004), and decide for yourself.
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Asparavis, a new Cretaceous bird from Mongolia: it is one of the earliest birds that lies in the direct ancestry of surviving birds today.
Press release from Yale University.
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A Web essay on Ichthyornis from the Oceans of Kansas Web site. Updated 2012.
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A Web essay on Hesperornis from the Oceans of kansas Web site. Updated 2012.
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A reconstruction of the flightless fishing bird Baptornis from the Oceans of Kansas Web site. Updated 2012.
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Cretaceous birds already had bird lice
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A Cretaceous duck? This is part of a huge argument about how many lineages of "modern" birds were present before the K-T boundary. The fossil is from the latest Cretaceous, but it is from Antarctica, so it won't be easy to try to collect more. The specimen is either an "unidentifiable bundle of bones", or has bones with unquestioned affinity to the Anatidae, the family to which modern ducks belong. I'm not willing even to guess who is right. It would be a surprise to me if the specimen really is an anatid, but stranger things have turned up.
Cenozoic Birds
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Songbirds had their origin (all of them) in Australasia. Press release. The paper is Barker, F. K., et al. 2004. Phylogeny and diversification of the largest avian radiation. PNAS 101: 11040-11045, and it is here: PNAS paper
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Titanis walleri, and other "terror birds". Careful -- it is Titanis not Titanus. Carl Zimmer article, 1997.
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Bullockornis from Australia. There is something about this bird that inspires purple prose: it has been called the "Demon Duck of Doom" (even in Wikipedia!) and the "Thunder Bird from Hell".
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Penguins
The Largest Flying Birds
Bats
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Flight in bats Slides from a lecture at the University of Maryland
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Tree of Life Website on Bats, with links at the end of the section.
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Short National Geographic feature on the bats of Barro Colorado, a very diverse concentration, June 2007
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A bat that eats birds: BBC News OnLine, August 2001.
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How vampire bats take off. (They jump high enough to get in a couple of powerful wing beats. This is not likely to have been the way that bats originally evolved flight.)
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How bats invented butterflies. BBC News OnLine, January 2000. Some moths may have evolved into day-flying butterflies to avoid nocturnal bat predation. (No evidence for this story, but it sounds plausible.)
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Some bats have evolved ultraviolet vision: stories from October 2003. Press release about a new paper in Nature. Here is another version of the release with a picture of the bat. Mammals lost color vision: only primates as a major clade re-evolved it. This bat from tropical America searches for nectar in the dark, and is also color-blind. What it has done is to "push" its black-and-white vision into the ultraviolet (the flowers it visits bloom at night, and their petals reflect whatever little light there is, with very high reflections at ultraviolet wavelengths). This looks like impressive co-evolution to me. We will have to wait for more studies on more nectar-sipping bats to see how common it is. It is a very laborious business to do the experiments, however. The paper is at Nature 425: 612-614, but of course Nature does not make its contents universally available on the Web.
The reference list for Chapter 13
Page last updated, April 7, 2013
Links last checked March 15, 2013
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