Life Sciences
clock | May 2, 2008Hypotheses leading to more hypotheses (from March 19, 2006 - the Malaria Day):
I have written a little bit about malaria before, e.g, here and here, but this is my special Malaria Action Day post, inspired by a paper [1] that Tara sent me some weeks ago and I never got to write about it till now.
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In a journal called "Medical Hypotheses" Kumar and Sharma [1] propose that jet-lagged travellers may be more susceptible to getting infected with malaria. They write:
Rapid travel across several time zones leads to…
clock | May 1, 2008You probably realize by now that my expertise is in clocks and calendars of birds, but blogging audience forces me to occasionally look into human clocks from a medical perspective. Reprinted below the fold are three old Circadiana posts about the connection between circadian clocks and the bipolar disorder, the third one being the longest and most involved. Here are the links to the original posts if you want to check the comments (especially the first comment on the third post):
January 18, 2005: Clocks and Bipolar Disorder
August 16, 2005: Bipolar? Avoid night shift
February 19, 2006:…
clock | April 30, 2008Single-celled Bacterium Works 24/7:
Researchers at Washington University in St. Louis have gained the first detailed insight into the way circadian rhythms govern global gene expression in Cyanothece, a type of cyanobacterium (blue-green algae) known to cycle between photosynthesis during the day and nitrogen fixation at night.
How Birds Navigate: Research Team Is First To Model Photochemical Compass:
It has long been known that birds and many other animals including turtles, salamanders and lobsters, use the Earth's magnetic field to navigate, but the nature of their global positioning…
clock | April 30, 2008As we mentioned just the other day, studying animal behavior is tough as "animals do whatever they darned please". Thus, making sure that everything is controlled for in an experimental setup is of paramount importance. Furthermore, for the studies to be replicable in other labs, it is always a good idea for experimental setups to be standardized. Even that is often not enough. I do not have access to Science but you may all recall a paper from several years ago in which two labs tried to simultaneously perform exactly the same experiment in mice, using all the standard equipment, exactly…
loom | April 30, 2008In my last post I wrote about how scientists are learning about the origin of animals by studying their genomes. One of the surprising findings of the latest research is that a group of animals called comb jellies (ctenophores) belong to the oldest lineage of living animals. Comb jellies look a bit like jellyfish--soft, tentacled creatures without brains or eyes but with a nervous system. As I wrote in the Boston Globe Monday, earlier studies had generally pointed to sponges as belonging to the oldest lineage. If comb jellies take their place, that may mean that the ancestors of sponges lost…
laelaps | April 30, 2008
The skull of Paranthropus boisei (AKA "Zinj," "Dear Boy," "Nutcracker Man," etc.). From Ungar et al. 2008.
Ever since the discovery of the hominds we call Paranthropus robustus in 1938 and Paranthropus boisei in 1959, the dietary habits of these "robust australopithecines" have been controversial. With skulls that seem to have more in common with gorillas than with Homo habilis, another hominid more closely related to us that lived during the same time, it has long been thought that Paranthropus was a dietary specialist. The saggital crest, large and thickly-enameled teeth, and huge jaws…
clock | April 29, 2008Birds Can Detect Predators Using Smell:
Many animal species detect and avoid predators by smell, but this ability has largely been ignored in the study of birds, since it was traditionally thought that they did not make use of this sense. However, it has now been discovered that birds are not only capable of discerning their enemies through chemical signals, but that they also alter their behaviour depending on the perceived level of risk of predation.
Help For Insomnia Patients? Different Processes Govern Sight, Light Detection:
A Johns Hopkins University biologist, in research with…
petnoyer | April 29, 2008This is the second in a series of five referenced articles about shared characteristics between deep and shallow water corals
Special guest post by Christina A. Kellogg
Just as humans have beneficial bacteria living on our skin and in our intestines, corals have symbiotic microbes in their mucus, tissues, and skeletons. Unfortunately, there are also disease-causing microbes that can infect corals. These coral-associated microbes include all three of the major domains of life: Bacteria, Archaea, and Eukarya (fungi, and in shallow-water corals, algae) and also viruses (Rosenberg et al. 2007…
tetrapodzoology | April 28, 2008
More recollections from the CEE Functional Anatomy meeting: part I is here. We looked in the previous article at Robin Crompton's overview of primate locomotor ecology and evolution, Renate Weller's overview of new technologies, John Hutchinson's work on dinosaur biomechanics, and Jenny Clack's new look at Ichthyostega [adjacent image is Jaime Chirinos's Thylacoleo restoration]. Still loads more to get through...
Paul O'Higgins took us back to primates. His key message was that two distinct computational techniques used to study anatomy - geometric morphometrics and finite element analysis (…
edyong | April 28, 2008
They say that size doesn't matter, but try telling that to bacteria. Most are very small, for they rely heavily on passive diffusion to ferry important nutrients and molecules across their membranes. To ensure that this happens quickly enough, bacteria need to ensure that their surface area is large enough relative to their volume - become too big and they won't be able to import enough nutrients to support their extra size.
These constraints greatly limit the size of bacteria. The larger ones solve the problem by being extremely long and slender, or by using an internal compartment called…
bleimanb | April 28, 2008UPDATE: Looks like the fount of wisdom that is The Time's Online lost a thing or two in the translation. Lucky for us, informed Zooillogix reader and sometimes D&D player, Dragon's Sorrow End, has set the record straight.
The government of Switzerland has passed the most comprehensive laws in the history of pet ownership to protect the well being of social animals. In hopes of creating an "informed population," the laws cover everything from guinea pigs to rhinoceroses. Here are some of the more interesting regulations:
- Dog owners are required to become qualified in a two-part course…
esiegel | April 28, 2008Old man Dave writes to me about his back problems:
The spine. I want to know about the spine. I know you are not that kind of PHD but still……. I’ve had back problems most of my adult life. It seems to me if we were “intelligently” designed that we might have a more efficient, and less troubling, method of uprightedness…. given the way the spine is constucted isn’t it possible that we were not “made” to walk upright??
Well, the spine goes back a long time, Dave, long before you were busting yours trying to lift things with your back instead of your legs. (You know better, Dave!) There are…
grrlscientist | April 28, 2008tags: Birds in the News, BirdNews, ornithology, birds, avian, newsletter
"Abstract"
Male Wood Duck, Aix sponsa.
Image: John Del Rio. [larger view].
Birds in Science
It wasn't too long ago that paleontologists thought that fossilization was a process where all biological material was replaced with inert stone. However, in 2005, Mary Higby Schweitzer of North Carolina State University rocked the paleontological world when she recovered a still-elastic blood vessel from inside a fractured thigh bone fossil of a Tyrannosaurus rex that lived 68 million years ago. Recent phylogenetic analyses of…
tetrapodzoology | April 28, 2008
At a vertebrate palaeontology workshop held in Maastricht in 1998, some colleagues and I sat in a bar, lamenting the fact that nobody cared about anatomy any more, and that funding bodies and academia in general were only interested in genetics. Given the poor to non-existent coverage that anatomy gets in many biology courses and textbooks, you might think that anatomy has had its day and that - as some molecular biologists told us in the 1980s and 90s - all the anatomical work worth doing had been published in the days of Owen and Huxley. Nothing could be further from the truth, and if you…
clock | April 27, 2008This post is a relatively recent (May 24, 2006) critique of a PLoS paper.
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There is a new study on PLoS - Biology that is getting some traction in the media and which caught my attention because it was supposed to be about circadian rhythms. So, I downloaded the paper and read it through to see what it is really about.
Well, it is a decent study, but, unfortunately, it has nothing to do with circadian rhythms. Many examples of tritrophic relationships involve parasitoids (usually small wasps) being attracted by plant volatiles which are…
laelaps | April 27, 2008After the success of The Lost World: Jurassic Park, the minds behind the franchise were in a bit of a fix. Tyrannosaurus and "Velociraptor"* had the run of the fictional islands for the past two movies; something new was needed to up the ante. The decision was made to make Spinosaurus the new villain in Jurassic Park III, the strange theropod being said to possess an 8-foot-long skull and stretch 60 feet from the tip of its crocodile-like snout to the end of its tail by the creative team. As if this weren't enough, the writers of the film had Spinosaurus kick the tar of of Tyrannosaurus,…
tetrapodzoology | April 24, 2008
The unusual fossil mammal skull posted here yesterday was, of course, that of the astrapotheriid astrapothere Astrapotherium magnum, as many as you said. But I'm a bit surprised that more people didn't get it straight away, given that astrapotheres were covered and covered again at Tet Zoo only a couple of months ago. However, I suppose that reading about something doesn't necessarily mean that you know how to identify its fossils... I'm still planning to post a write-up of the CEE Functional Anatomy meeting here ASAP, but haven't had time to finish it yet. Meanwhile...
... the modern animal…
laelaps | April 23, 2008
A female lowland gorilla (Gorilla gorilla) photographed at the Bronx Zoo.
By the year 1799, the Great Chain of Being had effectively been sundered, although some still clutched the shattered links in the hope that some linear order to the Creation would be found. The concept was no longer tenable, Charles White having to base his entire case for the superiority of Europeans over people of Asian and African descent (each "race" acting as a species to fill in a slot in the chain of "lower" to "higher") in An Account of the Regular Gradation in Man, and in Different Animals and Vegetables on…
oracknows | April 23, 2008I knew there was a reason why I like bioethicist Art Caplan.
Leave it to him not to be afraid not only to wander a bit afield of medicine than usual but also to call it as he sees it, mainly his argument for why Expelled! and its claim that "Darwinism" led directly to the Holocaust is not only historically incorrect but a form of Holocaust denial. I don't quite agree with him, but he makes a compelling argument:
The movie seeks to explain why, as a matter of freedom of speech, intelligent design should be taught in America's science classrooms and presented in America's publicly funded…
clock | April 23, 2008This is the sixth post in a series about mechanism of entrainment, running all day today on this blog. In order to understand the content of this post, you need to read the previous five installments. The original of this post was first written on April 12, 2005.
A Phase Response Curve (PRC) can be made in three ways:
One can construct a PRC for a single individual. If you have a reasonably long-lived organism, you can apply a number of light pulses over a period of time. The advantage is that you will always know the freerunning period of your organism, and you will know with absolute…