The Evolution of Flight

CHAPTER 13: UPDATES

  1. OCTOBER 2005. NEW THOUGHTS ON PTEROSAUR FLIGHT (p. 181)
  2. FEBRUARY 2005. Gliding Ants (p. 179)

  1. 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.

  2. 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

Lecture Notes on weed seed dispersal

Flight in Insects

P. 178. 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. 179. Parachuting Vertebrates

P. 179. Early Gliding Vertebrates

Pterosaurs

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.

Emery, N. J., and N. S. Clayton 2004. The mentality of crows: convergent evolution of intelligence in corvids and apes. Science 306: 1903-1907. When you read it, you will find that corvids (crows) are on the same level as primates in terms of intelligence and learning (tool use, for example).

How clever are crows?

The Solnhofen Limestone

Home of Archaeopteryx, the earliest bird, and many beautiful pterosaur fossils.

Early Birds, including Archaeopteryx

The Origin of Feathers

The Origin of Powered Flight in Birds

The Arboreal Hypothesis

I have to say that I think the arboreal hypothesis is so weak that it's not worth writing about. See a brief note that I wrote.

The Display and Fighting Hypothesis

The WAIR hypothesis

was published in January 2003. Here is the paper, by Ken Dial. (Thank you, Science!). Stories at the time:

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 the majority opinion is that Archaeopteryx could fly. . (Article on EvoWiki.)

I suspect, however, that Archaeopteryx could not fly. Part of the problem as I see it, as I say in the book, is that Archaeopteryx could not have had an effective upstroke without the supracoracoideus system.

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, and will discuss them here eventually. 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... Stay tuned. Here is the paper, rightly or wrongly posted on the Web, but not by Nature. And here is a story from the San Francisco Chronicle.

For my latest take on the lack of flight in Archaeopteryx, see this mini-essay from August 2004.

Earlier Bird Evolution?

New Cretaceous Birds

New discoveries of Cretaceous birds and close relatives: