Science
pharyngula | October 31, 2009This talk should put me back in my comfort zone—developmental biology, evolution, and fish, with the stickleback story, one of the really cool model systems that have emerged to study those subjects.
What is the molecular basis of evolutionary change in nature? How many genetic changes are required to produce new traits? Which genes are used? What types of mutations? Few or many changes required?
The dream experiment would be to cross a whale and a bat and figure out what their genetic differences are. That's impossible, so they searched for other organisms with a suite of differences that…
pharyngula | October 31, 2009Darwin had problems with the fossil record that he explained as a result of imperfections. Modern paleo has corrected some of that with the discovery of many intermediates. Jablonski is going to talk about the fossil record as a laboratory for testing evolutionary hypotheses. Marine bivalves are model systems with both modern forms and good fossil preservation for developing analysis techniques.
The fossil record gives access to raw rates of development, unique events, and long intervals, spatial dynamics, and morphological transitions in form.
Extinction in the fossil record is a problem.…
grrlscientist | October 30, 2009
Image: wemidji (Jacques Marcoux).
Nam et ipsa scientia potestas est (And thus knowledge itself is power)
-- Sir Francis Bacon.
Have you read an especially good essay about science, nature or medicine lately? If so, why not share it with the world by submitting the URL for this essay to a blog carnival designed to share excellent writing with others? You don't need to be the author of an essay to submit it for consideration, and this is one way that blog carnivals grow in size and influence: by sharing with others.
Scientia Pro Publica (Science for the People) was just published recently…
pharyngula | October 30, 2009A phylogeny is a statement about the evolutionary history of organisms. Cladograms give branching order only, but phylograms include branch lengths as well. They inform us about diversification of lineages, patterns and rates of trait evolution, and the ages of taxa and timing of radiations.
The tree is a model for the history of life at the macroevolutionary level. Darwin fully embraced the idea.Trees now being built with DNA sequence data, using improved phylogenetic algorithms and increased computational power. We now have many well-supported phylogenies backed up by multiple lines of…
pharyngula | October 30, 2009Lander began by saying he wasn't an evolutionist — an interestingly narrow definition of the term. He's a fan of the research, but considers himself a biomedical geneticist, as if that was something different.
Having entire genomes of many species available for quantitative analysis is going to lead to a qualitative change in the science we can do.
He gave a pocket summary of the human genome project. Mouse genome followed, then rat and dog, and now have sequence (to varying degrees of completeness) of 44 species, out of 4600 mammals. Within Homo, there's the hapmap project and the 1000…
pharyngula | October 30, 2009Earlier today, Jerry mentioned to me that he noticed my earlier blog posts on the meeting, and thought I wasn't being critical enough. So I think that means I'm supposed to let my inner beast out for this one. (Nah, actually, it's because I'm in note-taking transcription mode while listening to these talks. I have to digest them for a bit before I can do any synthesis.)
What is the biogeography of speciation? Can one species split into two while splitting into two? Allopatric speciation: no gene exchange; Parapatric: limited exchange; Sympatric: free gene exchange. Allopatric is sort of the…
pharyngula | October 30, 2009How do we distinguish bacterial species? Cohan shows us some nice diagrams of phenotypic and molecular clusters, and they show groups separated by gaps — therefore, species. Unfortunately the species defined thereby are big and contain considerable diversity within them. Darwin defined species as divergent forms between which one finds morphological gaps. Mayr: cohesive set of organisms whose divergence is constrained by genetic exchange. Speciation requires a breakdown of that exchange.
Mallet has developed a version of Darwin's species definition that includes molecular characters. Under…
pharyngula | October 30, 2009Oops, missed the first part of this talk due to the distractions of Lunch. Walked in as he was talking about tree vs. ladder thinking (people have a hard time conceptualizing trees) and history as a chronicle — barebones description of events — or a narrative — events linked by causal explanations.
It took a century for biologists to use systematics to make testable hypotheses about evolution. Darwin himself talked at length about all kinds of evidence for evolution, but strangely neglected fossils and dinosaurs altogether. Sereno blames this on rivalry with Richard Owen, who was the big…
pharyngula | October 30, 2009How do we explain the diversity of species in the world? The core process is speciation, a splitting of a lineage into two divergent lines that at the end, cannot interbreed. What do we know about speciation in Darwin's finches?
They evolved from a common ancestor in 2-3 million years into 14 different species, filling different ecological niches in the Galapagos, largely free of human interference. Showed us photos of four different species with very different beaks.
Developed predictions of population density from things like available biomass, and worked out relationship of expected…
awild | October 30, 2009
Tribolium castaneum, the Red Flour Beetle
Here's a beetle that the genetics-inclined entomologist will recognize. Tribolium castaneum, the red flour beetle, was the first Coleopteran to have its genome sequenced.
This small tenebrionid is native to the Indo-Australian region but has become a pest of stored grains around the world. I photographed these individuals from a lab culture at the University of Arizona where they were being used in studies on beetle development.
Photo details: Canon MP-E 65mm 1-5x macro lens on a Canon EOS 20D
ISO 100, f/13, 1/250 sec, diffused flash
pharyngula | October 30, 2009I have wireless access in the lecture hall today, so I'm going to try liveblogging these talks. This may get choppy! What it will lack in editing will be compensated for by more timely and regular updates. I hope. At least I'll be able to dump something to the site every 40-60 minutes.
He summarizes the idea that there is a wealth of genetic diversity in populations to allow for effective selection. Lack of mutations should not limit a straightforward selection response. This raises a paradox, however: organisms have phylogenetic niche conservatism. Many species are evolutionarily…
pharyngula | October 30, 2009Whoa. This was a data-rich talk, and my ability to transcribe it was over-whelmed by all the stuff Hauser was tossing out. Unfortunately, I think the talk also suffered from excess and a lack of a good overview of the material. But it was thought-provoking anyway.
One of the themes was how people resolve moral dilemmas. He began with a real world example, the story of an overweight woman in South Africa who insisted on joining a tour exploring a cave, and got stuck in the exit tunnel, trapping 22 people behind her. Do you sacrifice one to save many? One of the trapped people was a diabetic…
pharyngula | October 29, 2009It was a fine evening here in Chicago, with all these superstars of evolutionary biology in attendance. It was also an information-dense evening — I tried to keep up on my little laptop, but I know I missed a lot. Fortunately, I'm not alone: Rob Mitchum and Jeremy Manier were also covering the event, and have a play-by-play available. I'll just dump what I've got here tonight. I do have wi-fi passwords so I can get things up a little more promptly tomorrow and Saturday.
Richard Lewontin opened up with a few deprecatory comments about the religiosity of our surroundings (the talks were given…
catdynamics | October 29, 2009
You either get this or you do not.
courtesy John F. (click to embiggen)
Loathe as I am to admit it, that is rather good.
Hm. E/mc √(-1) pV/nR is way too derivative.
Maybe Q/V √-1 pV/nR
Or,
Q/V √-1 4√(P/A ε σ)
yeah, that's the ticket!
nRT/V kBln(Ω) (TS - pV)
has potential though.
Especially in that nice blue & white.
Right sub-field also...
pharyngula | October 29, 2009Here's part of an explanation I've liked for a long time: they're a product of developing cognitive processes that bias the brain to model the world with supernatural shortcuts.
(Moved below the fold because the silly video defaults to autoplay.)
grrlscientist | October 28, 2009
Image: wemidji (Jacques Marcoux).
Nam et ipsa scientia potestas est (And thus knowledge itself is power)
-- Sir Francis Bacon.
Have you read an especially good essay about psychology, behavior or neurobiology lately? If so, why not share it with the world by submitting the URL for this essay to a blog carnival designed to share excellent writing with others? You don't need to be the author of an essay to submit it for consideration, and this is one way that blog carnivals grow in size and influence: by sharing with others.
Scientia Pro Publica (Science for the People) was just published…
pharyngula | October 28, 2009I'm liking these CreatureCast videos from Casey Dunn — I showed the first in this series, now here's the second. It uses very simple animation to illustrate basic concepts…like the evolution of multicellularity in this one.
CreatureCast Episode 2 from Casey Dunn on Vimeo.
drorzel | October 28, 2009Some time back, commenter HI won a guest post by predicting the Nobel laureates in Medicine. He sent me the text a little while ago, and I've finally gotten around to posting it (things have been crazy around here):
Since Chad gave me the right to guest blog as a prize for correctly predicting the Nobel Prize winners, I thought it would be appropriate to write a post about the Nobel Prize. (It would have been more timely if I had written this sooner. This is why I'm not a real blogger.)
It was fun to be able to predict some of the Nobel Prize winners this year and last year. It is more…
drorzel | October 28, 2009Here's an extremely dorky Dorky Poll topic. I can't believe I haven't used this one before:
What sort of particles do you prefer?(poll)
Choose only one.
pharyngula | October 27, 2009Why? Because Jerry Coyne can mention this amazing conference, I can take a look at the luminaries speaking at it, and decide at the drop of a hat that I'm going. So this weekend, I'll be spending my Halloween at a major conference on evolution. Yay!
Look forward to lots of liveblogging (I hope…if they have wi-fi in the conference halls. If not, there will be some massive data dumps in the evenings.)