evolution
evolvingthoughts | June 8, 2008
Mystery Rays from Outer Space has a good essay on the evolution of spumaviruses ("foamy viruses") which are cytologically fatal in the lab, but which are latent in most body cell types in the nonhuman species they inhabit. It turns out that they have evolved over a long time to be nonvirulent by only infecting epithelial cells that are somatic dead-ends anyway, as they are about to be shed, and so they don't measurably affect the fitness of their hosts.
This leads directly to the question: why do some pathogens (viruses, bacteria, fungal infections etc.) evolve to low virulence ("virulence…
evolvingthoughts | June 8, 2008
A blog that I have just come across is Deric Bownds' Mindblog. He covers issues of standard and evolutionary psychology and is well worth reading. One of his posts is this: Social heirarchy, stress, and diet, in which he presents recent evidence that stressed primates (in this case humans) eat lower quality, high sugar and high starch, food (crisps and M&Ms).
Why? I can think of several reasons. One is that this gives immediate energy release to deal with the stressors. But what if you are constantly stressed, by, say, being of low status on the social dominance hierarchy? Then you…
evolvingthoughts | June 7, 2008
The final of my comments on this topic (see one and two here) addresses the question whether or not there is a rank of species.
Once I had a paper knocked back by a reviewer in which I argued that there was nothing unique to being species. This became my 2003 paper. The reviewer said that the paper failed to accept that there was a "grade of organisation" in biology that comprised species. This was not surprising as the paper argued that no such grade existed (and I was able to convince the editor that this was a decent argument to make). However, many biologists are convinced such a rank…
jrosenhouse | June 7, 2008Here's an interesting essay from Michael Ruse, published in the Georgia newspaper the Rome News-Tribune:
So why should we take the idea seriously? Why should we ever think that it could ever be much more than a “theory,” meaning an iffy hypothesis like speculations on the Kennedy assassination? Why should we ever agree that evolution is a “fact”?
Darwin realized full well that often we don't have direct evidence, but that doesn't stop us from talking about facts. Indirect evidence can be overwhelming. It can trump direct evidence even! Take a murder, or some other crime against the person.…
sa smith | June 6, 2008As you all heard from PZ, WHOOOO!!! Oklahoma governor Brad Henry vetoed Kerns 'Crazy Christian Bill of the Week' (I told you he is a nice guy).
As Vic Hutchison, head of Oklahomans for Excellence in Science Education noted in his newsletter to OKers, Gov. Henry could have let this bill just die. But he didnt. He vetoed it.
This is a major victory for supporters of separation of church and state and of quality in public education. LARGE numbers of individuals sent messages to legislators and the Governor in opposition to this bill as it worked its way through the process. To those, and to…
laelaps | June 6, 2008I have no idea where it came from (I assume it was made by PBS), but I just happened to stumble across this program all about Stephen Jay Gould called "This View of Life."
Watching the documentary is a bit strange because I never knew the young, gangly Gould. The first time I ever saw him on television (although I had no idea who he was), he was a stouter man talking about paleontology in a European museum, Palaeotherium being associated with the memory although I can't really recall how. In any case, it's definitely interesting to watch this program now, and I do appreciate the brief…
clock | June 6, 2008Bjoern Brembs alerts me to a cool new paper (OA so you can read the whole thing) - The great opportunity: Evolutionary applications to medicine and public health by Randolph M. Nesse and Stephen C. Stearns:
Evolutionary biology is an essential basic science for medicine, but few doctors and medical researchers are familiar with its most relevant principles. Most medical schools have geneticists who understand evolution, but few have even one evolutionary biologist to suggest other possible applications. The canyon between evolutionary biology and medicine is wide. The question is whether they…
evolvingthoughts | June 4, 2008
This is a kind of scattered post on a few things that have caught my eye, while I am avoiding boring work.
Paeloblog reports that a paper in Nature has done a phylogeny on continuous rather than discrete characters, using morphometric criteria to do a hominin phylogeny. This is not the first such attempt to use continuous characters in cladistics, and I would be interested if those who understand this topic comment on this attempt. It seems to me that the main difference between discrete and continuous data would be that the continua are an ordered set of otherwise discrete data points, so…
zooillogix | June 4, 2008A fascinating article in Livescience reveals the answer to a century-old zoological mystery: what do y-larvae grow up to become? Discovered in 1899, y-larvae are clearly young crustaceans but their adult stage could not be determined. While this in itself was perplexing, the newly discovered answer is even more startling: y-larvae metamorphosize into "simple, pulsing, slug-like masses of cells... far simpler than their larval stage." In a sense, the creatures revert backwards to forms more commonly seen further down the evolutionary ladder as they mature.
Watch the process
This awesome video…
laelaps | June 4, 2008In the course of rooting through the literature for more information on Eohippus, Hyracotherium, and the various associated genera (it's been a chore to find out their names, much less the relevant papers!) I stumbled across this 1927 poem by Richard Ashman, published in The Science News-Letter. It is obviously not meant to be accurate, but I have to say that the concluding verses made me laugh.
The Diplo-doclodipus
A sad young Eohippus, once,
Who pattered through the gorse,
Was sobbing as he pattered, for
His fondest hopes were shattered, for
He'd failed in all that mattered, for
He wasn't…
laelaps | June 4, 2008Even though I said that I had more pertinent material to read than discourses about the perceived clash of science & Christian theology, I contradicted myself by picking up John Hedley Brooke's Science and Religion last night. As I have become increasingly aware during the course of my reading, the present climate of argument around science & religion carries a tone of conflict and warfare that has been maintained for over 100 years the more. It is fashionable to invoke such imagery, religion slowly crumbling under the weight of science, but a historical perspective reveals…
evolvingthoughts | June 2, 2008
Creationism is being pushed legislatively in Texas again. But this line is priceless, from State Board of Education vice chairman, David Bradley (yes, you guessed, a Republican):
Bradley said he doesn't foresee any successful effort to remove the “strengths and weaknesses” requirement from the science standards.
“There are issues in the evolutionary process that have been proven wrong,” he said. “Evolution is not fact. Evolution is a theory and, as such, cannot be proven. Students need to be able to jump to their own conclusions.”
After all, if the grownups can jump to their own…
edyong | June 2, 2008
When it comes to evolution, a species' past has a massive bearing on what it might become. That's the latest message from a 20-year-long experiment in evolution, which shows how small twists of fate can take organisms down very different evolutionary paths.
The role of history in evolution is a hotly debated topic. The late Stephen Jay Gould was a firm believer in its importance and held the view that innocuous historical events can have massive repercussions, often making the difference between survival and extinction. To him, every genetic change is an "accident of history" that makes…
laelaps | June 2, 2008Of all the concepts of nature I have so far encountered in my research on the history of evolution as an idea, few (if any) are as virulent as the Great Chain of Being. Although Stephen Jay Gould claimed that White's 1799 book An Account of the Regular Gradation in Man, and in Different Animals and Vegetables represents the last gasp of the Great Chain of Being the idea was not simply discarded or forgotten. While the concept ultimately failed to make sense in terms of the ordering of nature it found a refuge in evolutionary theory, particularly in considerations of how humans are related to…
awild | May 31, 2008
30 years ago, biologists thought they'd solved one of Darwin's thorniest problems, the evolution of sterile social insects:
No doubt many instincts of very difficult explanation could be opposed to the theory of natural selection,âcases, in which we cannot see how an instinct could possibly have originated...I will not here enter on these several cases, but will confine myself to one special difficulty, which at first appeared to me insuperable, and actually fatal to my whole theory. I allude to the neuters or sterile females in insect-communities: for these neuters often differ widely in…
sa smith | May 31, 2008So almost exactly a year ago, Michael 'LiLo' Behe released his prized pig book, 'Edge of Evolution', where he stated, with utmost certainty, that HIV-1 'has not evolved'.
Yeah, that hasnt worked out too well for him.
Anyway, unlike Ivory Handed Creationists who dont lower themselves to doing anything as dirty as 'research', scientists have kept busy seeking out new proteins within our own bodies to explain some weird evolution in the Vpu gene of HIV-1. Turns out there is a component of the innate immune system that we didnt even know existed before we followed the trail of Vpus 'unimpressive…
evolvingthoughts | May 30, 2008
So we managed to attract 5 local PZombies (Craig, you are in trouble for not turning up!) on a wet Brisbane night. We had some interesting discussions (which I fear means that others listened to me nonstop) over beer. It's nice to know that those of us who are in thrall to our cephalod overlords are not alone in our struggle to conquer the world and make it safe for molluscs. But to show the superiority of cephalopods over chordates, watch this:
pharyngula | May 29, 2008I've discovered a couple of important things at this meeting.
One, late night sessions at west coast meetings are deadly for any of us coming from more eastern time zones. At least the morning sessions are low stress.
Two, I haven't heard one Drosophila talk yet, and the message is clear: we're now in the stage of evo-devo in which everyone is diversifying and chasing down a wide array of species. There was a bit of model-system bashing, but at the same time, everyone is acknowledging the crucial role of those traditional, but weird and derived, lab critters in providing a point of comparison…
loom | May 29, 2008I have been meaning for some days now to point your attention to my new article in the June issue of Scientific American called, "What Is A Species?" The hard copy is worth tracking down because it's got a lot of excellent illustrations and sidebars. SciAm has the full article online for subscribers, and I've posted the text over at carlzimmer.com.
There's so much I could say on the topic--pointing out how the recent news on polar bear extinction raises the question of how distinct polar bears are, for example--but I am scurrying in the shadow of a rising wave. (Attention people of Portland,…
gregladen | May 28, 2008... But don't panic. Apparently, this is normal.
It turns out that bacteria living at the bottom of the sea are far more abundant and diverse than scientists had previously thought. These bacteria appear to be consuming the planet's oceanic crust. This raises several interesting questions regarding the interaction and co evolution of life on Earth and the Earth itself.
[UPDATED]
This is all according to a paper being published May 29 in Nature. According to one of the study's authors, Katrian Edwards of USC:
A 60,000 kilometer seam of basalt is exposed along the mid-ocean ridge…