evolution
gregladen | January 3, 2008
New research published in Science on the origins of multicellular life reveals an interesting pattern. The Cambrian Explosion may have been samosamo.
What is evolution about? Why are there different species, rather than just one (or a few) highly variable species? Is there a close correspondence between the ecological "spaces" that organisms can fit and the adaptations ... represented by morphology, for instance ... of the species that do exist? Can you imagine a different world where instead of having 10,000 species of birds there is only one bird that is highly adaptable in its…
gregladen | January 3, 2008Daily alcohol use by males has been shown to increase sexual arousal and decrease sexual inhibition.
In Fruit Flies.
The current (Jan 2) issue of PLoS ONE includes a paper by Lee et al exploring thye physiological side of changes in sexual behavior under the influence of alcohol, with an eye towards understanding this process in humans, using an animal model.
Alcohol has a strong causal relationship with sexual arousal and disinhibited sexual behavior in humans; however, the physiological support for this notion is largely lacking and thus a suitable animal model to address this issue is…
jlynch | January 3, 2008The National Academy of Sciences’ new book, Science, Evolution, and Creationism is now available for free download. It is a revision of an older work and features chapters on the nature of science, the evidence for evolution, and creationist claims. No doubt the Discovery Institute will respond with its usual blather.
mikethemadbiologist | January 3, 2008Beta-lactam antibiotics, penicillin and all of its subsequent derivatives, are critical, life saving drugs. One way bacteria protect themselves from these antibiotics is by producing enzymes known as beta-lactamases that cleave the beta-lactam, rendering the beta-lactam antibiotic harmless. There are many different kinds of beta-lactams (such as CTX-M), and they differ in how common or rare they are.
A recent study examined looked at the role fitness might have in making TEM class beta-lactamases very frequent and found in many different species, and keeping SME class beta-lactamases rare…
loom | January 1, 2008Sorry to start the New Year on a down note, but the January 1, 2008 issue of the New York Times has a review I wrote about a book called No Way Home. It's a sobering look at the decline of the world's great migrations. I've written a fair amount about the marvels of migration in recent months (here, here, and here), so it's sad to see that there might not be much to write about in years to come unless the world gets its act together.
razib | January 1, 2008Richard Dawkins on his acceptance of The Handicap Principle:
Verbal arguments of this kind can take us only so far. Mathematical models are needed, and various people supplied them, notably John Maynard Smith who concluded that Zahavi's idea, though interesting, just wouldn't work. Or, to be more precise, Maynard Smith couldn't find a mathematical model that led to the conclusion that Zahavi's theory might work. He left open the possibility that somebody else might come along later with a better model. That is exactly what Alan Grafen did, and now we all have to change our minds.
I translated…
evolvingthoughts | December 31, 2007
The Grauniad has a puff piece on what has changed the minds of "the intellectual elite". It seems Alan Alda is one of them in virtue of his screen roles... still I have to like his comment:
Until I was 20 I was sure there was a being who could see everything I did and who didn't like most of it. He seemed to care about minute aspects of my life, like on what day of the week I ate a piece of meat. And yet, he let earthquakes and mudslides take out whole communities, apparently ignoring the saints among them who ate their meat on the assigned days. Eventually, I realised that I didn't…
evolvingthoughts | December 31, 2007
OK, so the next door party finished about 1.30, but the family disputes finished about 5 am, so instead of thinking, I'm going to let others think for me, and round up a few New Years Day links...
Wesley Elsberry at Austringer has a nice piece on why creationists use the conflict model for the relation of science and faith.
Thinking Meat asks if life was "nasty, poore, brutish and short" as Hobbes thought, or things were simply just as much about survival as they are now, in preagriculture.
PsyBlog asks how well Epicurus, one of my favourite Greek Philosophers, fares in the light of…
razib | December 31, 2007Rich Lawler has an insightful comment:
It's interesting to note that a few of the most insightful observations about the evolutionary process were first promulgated verbally, then later proven mathematically (unlike H-W equilibrium). These include runaway sexual selection (first adumbrated by Fisher, then shown mathematically possible by Lande and Kirkpatrick), the handicap principle (first adumbrated by Zahavi, then--finally--shown to be mathematically possible by Grafen), and, of course, natural selection (first adumbrated by what's-his-face, then formalized by Wright, Fisher, and later…
voltagegate | December 31, 2007It's quite simple really. Just leave out the details:
The near extinction of the western barred bandicoot has led to the identification of a novel virus exhibiting characteristics of two ancient virus families.
The western barred bandicoot (WWB), an Australian marsupial once commonly found across western and southern Australia, is now endangered throughout parts of the country and already extinct on the mainland. While promoting conservation efforts, researchers discovered a debilitating disease affecting the species causing full body lesions.
Papillomaviruses (PVs) and polyomaviruses (PyVs)…
pharyngula | December 31, 2007That friend to the Discovery Institute and creationist advisor to the Vatican, Cardinal Schönborn, has a new book out, titled Chance or Purpose?. I haven't read it, but Michael Behe has, and Zeno finds a particularly delicious Behe blurb:
Science cannot speak of ultimate purpose, and scientists who do so are outside of their authority. In Chance or Purpose? Cardinal Schöborn shows that the data of biology, when properly examined by reason and philosophy, strongly point to a purposeful world.
Why should science be incapable of addressing the questions of an ultimate purpose? I hear this all…
gregladen | December 30, 2007First, have a look at this (warning, large file):
wow
It is a PDF file of the unrooted mammal evolution tree that came from this research.
Now, here is a question for you. There is a rumor that this graphic or something like it has been converted to a poster for sale. Anybody know where to get one?
Thank you very much.
razib | December 30, 2007Laelaps has an excellent post up, Evolution's Arrow, which you should read. Set some time aside, it is long. I don't know enough about paleontology to comment with great insight on the many of the topics which Laelaps alludes to, and some of them get a bit philosophical for my own taste (that is, issues turn on the interpretation of words), but there is one point which I might assert is somewhat muddy:
...Looking at the hominid evolutionary bush pictured below [see here, it's clear that we are but a single surviving twig of a group that once had a much greater diversity, australopithecines (…
clock | December 29, 2007Two grape genomes were published this year, one in Nature, the other in PLoS ONE. Larry Moran explains the methodologies and results of both and discusses the trustworthiness of each. The Nature paper is explained in The Grapevine Genome, and the PLoS ONE paper is discussed in The Second Grapevine Genome Is Published. Obligatory Readings of the Day.
laelaps | December 29, 2007The evolution of life on earth has no direction and no predetermined end; what is adaptive today might not be tomorrow, and the scores of extinct creatures preserved in the rocks of this planet attest to an ongoing process that results in what Charles Darwin rightly called "endless forms most beautiful and most wonderful." The man hailed as the co-discover of natural selection, Alfred Russel Wallace, would not agree with my opening remarks, though. While Wallace contributed much to biological science in his own right, the incorporation of anthropocentric spiritualism into his hypotheses…
sporte | December 28, 2007If you look below the fold, you can see two molecules locked in a tight embrace. These molecules or their closely related cousins can be found in any cell because their ability to evolve is slowed by their need to interact with each other in the right way.
In an earlier post, I asked:
Who are they?
One partner is a small bit of 16S ribosomal RNA, about 56 nucleotides to be precise. The other partner is S15, one the proteins in the ribosome.
If we could look inside the bacteria that made these, we would see lots of other proteins binding to these two partners within a molecular machine.…
oracknows | December 28, 2007Lately, bloggers, including some of my fellow ScienceBloggers, have been expressing various concerns about the phenomenon that is Ron Paul, the Republican candidate who's ridden a wave of discontent to do surprisingly well in the polls leading up to the Iowa caucuses and New Hampshire primaries. First, Jake and Greg have pointed out that Ron Paul apparently does not accept the theory of evolution. The other day, Ed Brayton and Sara Robinson discussed a story about an open letter by Bill White, the leader of the American Socialist Workers' Party, in which White claimed that Paul and his aides…
laelaps | December 27, 2007
The famous footage of "Benjamin," a Thylacine that died in captivity due to neglect on September 7, 1936. It was the last known living member of its species.
Convergent evolution can be a tricky thing, and one of the most celebrated examples of it (at least among creationists) is the case of the extinct marsupial predator the Thylacine (Thylacinus cynocephalus, also known as the Tasmanian Tiger or Tasmanian Wolf). Indeed, when compared to the skull of a wolf (a placental predator), the differences between the skulls of the predators are so slight that anyone but an expert would easily…
mikethemadbiologist | December 27, 2007One of the lesser known microbiology facts is that the pathogen Shigella is actually E. coli. Since I'll be writing more about this cool bug soon, from the archives, here's an explanation (with a little modification).
As I mentioned in a previous post, Orac has two very good posts on MDs and creationism. In one of the posts, he links to a creationist medical student who writes the following:
Has anyone ever documented a plateful of Strep pneumo mutating into E coli? Or even into Strep pyogenes? I didn't think so. They mutate, and they exchange information. But they remain separate species…
razib | December 27, 2007Mark of Denialism left a comment below re: Vitamin D deficiency:
I wouldn't call that evidence thin biff. The role of vitamin D in tuberculosis was actually pretty well nailed by studies of immigrants in the UK which demonstrate that latent TB infections will reactivate in the sunless climate. The demonstration of the role of Vit D in making defensins seems the likely physiological explanation.
I am wary though of some of the more hyperbolic claims I've seen about vitamin D lately. It's fascinating stuff, sure. But until replicated in RCT rather than epidemiologically I think it's too early…