birds
clock | August 16, 2006I And The Bird #30 is up on Burning Silo. Get your birding blogging thirst quenched today!
clock | August 15, 2006
This post from March 27, 2006 starts with some of my old research and poses a new hypothesis.
The question of animal models
There are some very good reasons why much of biology is performed in just a handful of model organisms. Techniques get refined and the knowledge can grow incrementally until we can know quite a lot of nitty-gritty details about a lot of bioloigcal processes. One need not start from Square One with every new experiment with every new species. One should, of course, occasionally test how generalizable such findings are to other organisms, but the value of models is…
clock | August 15, 2006
One of the assumptions in the study of circadian organization is that, at the level of molecules and cells, all vertebrate (and perhaps all animal) clocks work in roughly the same way. The diversity of circadian properties is understood to be a higher-level property of interacting multicelular and multi-organ circadian systems: how the clocks receive environmental information, how the multiple pacemakers communicate and synchronize with each other, how they convey the temporal information to the peripheral clocks in all the other cells in the body, and how perpheral clocks generate…
clock | August 15, 2006
This post, from January 25, 2006, describes part of the Doctoral work of my lab-buddy Chris.
Mammals have only one circadian pacemaker - the suprachiasmatic nucleus (SCN). Apparently all the other cells in the body contain circadian clocks, too, but only the SCN drives all the overt rhythms. Without the SCN, there are no rhythms - the peripheral clocks either get out of phase with each other, or their clocks stop ticking altogether.
If you place various tissues in a dish, the SCN cycles indefinitely. All other tissues are capable of only a few oscillations in the absence of a daily signal…
clock | August 15, 2006
One of the important questions in the study of circadian organization is the way multiple clocks in the body communicate with each other in order to produce unified rhythmic output.
In the case of mammals, the two pacemakers are the left and the right suprachiasmatic nucleus (SCN). The tow nuclei are anatomically close to each other and have direct nerve connections between them, so it is not difficult to imagine how the two clocks manage to remain continuously coupled (syncronized) to each other and, together, produce a single output, thus synchronizing all the rhythms in the body.
In the…
clock | August 14, 2006Going into more and more detail, here is a February 11, 2005 post about the current knowledge about the circadian organization in my favourite animal - the Japanese quail.
Japanese quail (Coturnix coturnix japonica), also known as the Asian Migratory Quail, are gallinaceous birds from the family Phasianidae, until 1960s thought to be a subspecies of European migratory quail (Coturnix coturnix coturnix), but now considered to be a separate species, designated as Coturnix japonica. The breeding range of the wild population encompasses Siberia, Mongolia, northeastern China and Japan, while the…
clock | August 14, 2006
This post was originally written on February 11, 2005. Moving from relatively simple mammalian model to more complex systems.
I have previously described the basic properties of the circadian organization in mammals. Non-mammalian vertebrates (fish, amphibians, reptiles and birds) have more complex circadian systems than mammals. While the suprachiasmatic area remains a site of circadian pacemakers, it is, unlike in mammals, not the only such site.
The pineal organ, which in mammals is a purely secretory organ, is directly photosensitive in other vertebrates (with the exception of snakes)…
clock | July 21, 2006
Some plants do not want to get eaten. They may grow in places difficult to approach, they may look unappetizing, or they may evolve vile smells. Some have a fuzzy, hairy or sticky surface, others evolve thorns. Animals need to eat those plants to survive and plants need not be eaten by animals to survive, so a co-evolutionary arms-race leads to ever more bizzare adaptations by plants to deter the animals and ever more ingenious adaptations by animals to get around the deterrents.
One of the most efficient ways for a plant to deter a herbivore is to divert one of its existing biochemical…
clock | July 16, 2006Do you read Darren Naish's blog Tetrapod Zoology? If not, you should start now. Just check out some of the most recent posts, for example this two-parter on sea snakes: 'A miniature plesiosaur without flippers': surreal morphologies and surprising behaviours in sea snakes and Sea kraits: radical intraspecific diversity, reproductive isolation, and site fidelity.
Or, this two-part post about the importance of the shape of the birds' bills: The war on parasites: a pigeon's eye view and The war on parasites: an oviraptorosaur's eye view.
Or an amazing four-part story about Angloposeidon, a…
clock | June 21, 2006
A delightful World Cup-themed edition of I and the Bird is up on The Hawk Owls' Nest. A great round-up and an excellent example of creative hosting.
Next edition is the First Year Anniversary of the carnival, so it goes back home to 10000 Birds. The theme is "why you blog, why you bird, or why you blog about birds". Send your entries to Mike by July 5.
clock | June 15, 2006The Aquatic Ape theory is bunk, but Aquatic Sparrow theory just got a huge boost. There is no way I can explain the Big Evolution News Of The Day as well as Grrrlscientist did, so please go here and enjoy the amazing news of the wading/aquatic ancestors of all modern birds, with the beuatiful pictures of excuisitely well-preserved fossils from China.
clock | June 13, 2006SEED Magazine has an interesting article on the advances in avian transgenics....
I've been out of the loop for the past 3 or so years, but I took an Avian Biotechnology graduate class with Jim Petitte (mentioned in the article) a few years back, in which we did every step of the method separately, not really trying to make a transgenic chicken over a semester, but trying to figure out how to make each step work for us. The year I took it was the first time his class actually managed to produce a chimaera. Jim was so excited he was jumping up and down and hitting the ceiling - and he is a…
clock | June 9, 2006Friday, May 26th.
Morning
After such an exciting and exhausting first day, we gave ourselves the luxury of sleeping late on Friday. After grabbing some bagels and pretzels from street vendors, we took the kids on their first ever ride on the Underground. They were excited. Of course, we got on a wrong train which took us to Brooklyn. After we realized we have crossed a bridge, kids got nervous, but we just got out, crossed to the other side of the tracks and got on the same line in the other direction and back to Manhattan in minutes.
Interestingly, I did not find the NYC underground very…
clock | June 9, 2006Where did I get my Internet handle? Answer below the fold...
Many years ago, when my wife signed up for AOL (at the time when that was still a rational choice), all the rest of the family could add their own e-mail addresses. I thought it might be a good idea to have an AOL addresss to serve as a public address for everyone to know - spam and all.
So, I tried to pick various nice names but, nope, they were all taken, so in the end I thought nobody on Earth would have "coturnix". Well, one other person did, but I added number 1 to it and it's been serving me well for many years now. When…
cmooney | February 21, 2006Why is it that all birdwatching trips seem to end up the same way: You trudge along lengthy forest trails and freeze your ass off, only to find at the very end that the bird you were searching for was sitting in the parking lot the whole time? Such was my experience this weekend.
On Sunday we went to Virginia, to Occoquan Bay National Wildlife Refuge, to look for Bald Eagles and whatever else we could find. Except for some distant sightings of what may have been eagles, we didn't see squat. But then, while stuck in traffic on the way back to Washington, D.C., what did we see but a majestic…
cmooney | January 24, 2006How naive I am. I thought it was settled that the Ivory-Billed Woodpecker was back among us. I guess I was wrong. As an amateur birdwatcher, I also thought that the videotape provided of the bird was extremely convincing. But I guess I can't be too certain any more, as a real expert ornithologist doesn't buy it.
There's a lot of hope involved here, and hope can easily cloud our judgment. But once again--though I'm not an expert--I don't see how hope alone can explain the striking white outer wings of the bird in the video. My hunch, and it's only a hunch, is still that this is the real thing…