evolution
gregladen | January 18, 2008There is a discussion on the internet about Junk DNA, that includes a discussion at Sandwalk (Larry Moran's blog) ... I made a comment there about genome size that was responded to by T.R. Gregory. I started to write my response in Larry's Little Box, but realized that it would not fit. So it is here:
Imagine a gene family distributed among all the species in a given taxon. There are several alleles per gene. The gene codes for an enzyme that plays a role in determining cell size. Different combinations of genes/alleles exist to cause cell size to vary such that each species has a…
awild | January 17, 2008
Here's a story about a parasitic nematode that turns black ants into ripe red berries. What's this about?
The parasite needs to get its eggs from an infected ant to healthy ants. Apparently it hasn't been successful the old-fashioned way, just broadcasting its eggs about the environment. Instead, these little worms have figured out a far more effective egg delivery vehicle: birds.
Ants of the genus Cephalotes often feed from bird droppings (for instance, see here). If a parasitic egg can get itself into a bird's digestive system, it'll wind up in a juicy fecal pellet where it may be…
evolvingthoughts | January 17, 2008
Colin Purrington has a nice set of publicly available images for use in pro-science talks. Go check 'em out.
evolvingthoughts | January 17, 2008
OK, so by now a number of you are either quite puzzled or are up in arms about this notion of mine that genes aren't information. First I'll recap and then make some general philosophical and historical points.
I argue that something can only be said to be information bearing if it is isomorphic to one formalisation of what counts as an Information Processing System (IPS). Anything that doesn't have the requisite mapping between these formal descriptions and physical systems doesn't count. I further argue that genes do not show the right properties of these formal systems, and hence should…
grrlscientist | January 17, 2008tags: researchblogging.org, Josephoartigasia monesi, Giant South American rodent, fossils, megamammals, Dinomyidae
The head of the newly-found Josephoartigasia monesi (A), in comparison to a South American rodent known as a pakarana, Dinomys branickii (B).
Image: G. Lecuona [larger size].
As a resident of NYC, you often hear stories of enormous rats that are aggressive enough to fight an alleycat -- and win. Even though I watch the rats run around in the subways and am impressed by their audacity, I've never seen any rats that had reached a particularly impressive size, although I have…
oracknows | January 17, 2008Things are crazy now for me, both at home and at work. I mean really, really crazy. So crazy that even I, one of the most verbose bloggers out there, am forced to take two or three days off from my little addiction--I mean habit. Consequently, having foreseen that this time would come around these dates, I, Orac, your benevolent (and, above all verbose) blogger have thought of you, my readers. I realize the cries and lamentations that the lack of fresh material inevitably causes. That, I cannot completely obviate. However, I can ease the pain somewhat, and I can do this by continuing my…
gregladen | January 17, 2008Things are just not like what they used to be. You know this. You know that the Age of Dinosaurs, for instance, was full of dinosaurs and stuff, and before transitional fossil forms crawled out of the sea to colonize the land, all animals were aquatic, etc. But did you know that from a purely modern perspective, the Miocene was the most important geological period?
First, lets get one thing straight. We are not in the so-called "Holocene." The so-called "Holocene" is a totally bogus geological period. Saying "Hey, we're in the Holocene, not the Pleistocene ... the Pleistocene is over…
pharyngula | January 17, 2008I thought it might be useful for the readers of Pharyngula to get my sense of the Colbert show experience.
Being a scientist on the show carries with it some challenges. We need to convey facts of science correctly and do so in a way reveals how fun our science is to do and to think about. We need to educate, enlighten, and excite. The challenge is we need to do this in 5 minutes with Stephen Colbert sitting across the table. To make matters worse, the show does not tell you the tack Colbert is going to take in advance, largely because so much of what he does is ad lib.
Because of this,…
gregladen | January 16, 2008People from different cultures use their brains differently to solve the same visual perceptual tasks, MIT researchers and colleagues report in the first brain imaging study of its kind.
This is not that surprising, but it is very interesting research. We already knew, for instance, that people who read and write different "kinds" of languages ... pictographic vs. non-pictographic ... use different regions of their brain for this function, and thus are differentially affected by strokes or other damage.
This news comes to us from an MIT press release...
Psychological research has…
gregladen | January 16, 2008Traveling from Ecuador to Africa, Jane Goodall takes the audience on an ecological journey, discussing highlights and low points of her experiences in the jungle. She shows how progress is helping research (DNA analysis) and hurting the environment (clear-cutting). And she draws a dozen parallels between primate and human behavior, making the point that we really aren't all that different. Our big advantage, she says, is the ability to communicate with sophisticated spoken language -- yet, sadly, we are abusing this power and destroying the planet. She urges the TED audience to behave…
mikethemadbiologist | January 16, 2008The NY Times has an article about the MRSA (methicillin resistant Staphylococcus aureus) strain that is spreading rapidly among gay men. One factor is that a subset of the gay population is immunocompromised due to HIV, and consequently, is more likely to acquire MRSA skin infections.
This strain is very drug resistant, unlike most community-acquired MRSA ('CA-MRSA'). Most CA-MRSA, while resistant to methicillin, is sensitive to clindamycin. However, this strain has acquired a plasmid (a transferable 'mini-chromosome') that confer resistance to commonly-used drugs to treat MRSA:
"This…
gregladen | January 16, 2008Well, it is a good thing that I have a thick skin and a good sense of humor, or I would be very put off by Larry Moran and probably T. Ryan Gregory as well.
Apparently, I stepped into an ongoing partially ad hominem debate over "Junk DNA" centering on the work of John Mattick and his research group. In this post, I'd like to provide a clarification of my "position" on Junk DNA, and I'll spend a moment admonishing my colleagues for being dorks.
My offending post is here. This is a report on a recent paper by Mattick and others in which they provide evidence that non coding RNA does…
mikethemadbiologist | January 16, 2008By way of ScienceBlogling Razib, I came across this Reason article by Ronald Bailey summarizing the presidential candidates views' on evolution. Bailey highlights two reasons what lack of support for evolution says about a candidate:
The candidate probably is weak on the separation of church and state.
The candidate is unable to rationally assess evidence.
But I think this misses the point entirely: evolution matters because evolutionary biology matters.
Granted this sounds like something Yogi Berra would say, but I'm tired of the Coalition of the Sane, regardless of where individual…
oracknows | January 16, 2008It's been a while since I've dealt with creationists trying to claim either that evolutionary theory is not relevant to the problem of microbial resistance to antibiotics or, even worse, making really bad medical recommendations on the basis of their interpretation of evolution.
This time around RPM has posted a nice article on Competitive Release and Antibiotic Resistance that suggests a possible way that we can use evolutionary theory to prolong the useful life of antibiotics before resistance evolves. The results explained by RPM remind me of an article I blogged about several months ago,…
evolvingthoughts | January 15, 2008
Anyone who knows the film The Princess Bride knows what happens next. Westley gets hit hard by a rodent about the size of a pitbull. However, it seems that ROUS's (Rodents of Unusual Size) actually may have existed, in Uruguay. Nature reports that the skull of one has been discovered, and the animal itself may have weighed a tonne (2200lbs) or so.
Next, we'll discover that there are miracle men...
pharyngula | January 15, 2008Watch Neil Shubin discuss evolution on the Colbert Report — he's good. He convinced me to run out and order his new book, Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body (amzn/b&n/abe/pwll)!
grrlscientist | January 15, 2008tags: researchblogging.org, blind cave fish, Astyanax mexicanus, evolution, fish, genetics
Blind cave fish, Astyanax mexicanus.
Image: Orphaned. Please contact me for proper credit and linkage.
Do you keep tropical freshwater fishes? I have kept tropical fishes for most of my life and was always intrigued by the so-called "blind cave fish", Astyanax mexicanus, that were sometimes offered for sale to the public. These fish evolved from a sighted species that live in surface streams, but since the blind cave fishes lived in caves since the mid-Pleistocene or earlier, they were not exposed…
gregladen | January 15, 2008You know that organisms develop, grow, and function in part because genes code for proteins that form the building blocks of life or that function as working bioactive molecules (like enzymes). You also know that most DNA is junk, only a couple percent actually coding for anything useful. Most importantly, however, you know that everything you know is wrong. Right?
The "Junk DNA" story is largely a myth, as you probably already know. DNA does not have to code for one of the few tens of thousands of proteins or enzymes known for any given animal, for example, to have a function. We know…
pharyngula | January 15, 2008
Hagfish are wonderful, beautiful, interesting animals. They are particularly attractive to evolutionary biologists because they have some very suggestive features that look primitive: they have no jaws, and they have no pectoral girdle or paired pectoral fins. They have very poorly developed eyes, no epiphysis, and only one semicircular canal; lampreys, while also lacking jaws, at least have good eyes and two semicircular canals. How hagfish fit into the evolutionary tree is still an open question, however.
There is a strong temptation to see hagfish as representing an earlier grade of…
razib | January 14, 2008Over the past few weeks I've talked about the relationship of genes & biology to culture. First I noted the likely impact of the evolutionary arms race between our adaptive immune system and plagues & endemic infectious diseases upon the course of human history. Second, I pointed to the utility of phylogenetics in giving us another tool through which we have a window onto the past. But what about culture's affect upon our genes? The canonical example is probably lactose tolerance, or more precisely lactase persistence. In this case the adoption of dairy culture has resulted in…