evolution
awild | March 16, 2008
Pheidole creightoni major worker, California
After reading a couple times through Corrie Moreau's hot-off-the-press Pheidole evolution paper, I am pleased to give it a thumbs-up. The paper is behind a subscription barrier, so I have distilled the results into an informal summary:
Pheidole is one of the most important groups of ants. They are distinctive in always having at least two sharply-defined types of worker ants in the nest: minor workers that just sort of look like normal little ants, and the very front-heavy major workers with an enormous head and powerful jaws. Pheidole is…
jlynch | March 15, 2008John Wilkins and I have been at the Edges and Boundaries of Biological Objects workshop here in Salt Lake City for the past few days. John live-blogged some of the talks, so you may want to check his posts out. Lots of interesting stuff was discussed about populations (here and here), the fossil record (here), ecosystems (here and here), system dynamics and boundaries (here and here), DNA bar-coding (here and here), species, rank-free classification, and homology. All in all some really thought-provoking ideas that will take me a good while to digest.
Discussions are likely to continue at the…
evolvingthoughts | March 14, 2008
Roberta is a great philosopher from UC Davis and she's talking about the notion of populations.
Known she needed a definition of population for a long time - this is a first stab.
"Population" has many definitions by biologists. Most try to limit it by space or time or interbreeding. But very little analysis. We invoke it often - it needs a proper definition. Uses include conspecificity, arbitrary delimitation, geography, area and time, interbreeding, etc.
Second motivation based on selection and drift, which are processes that occur in populations. These processes become arbitrary if…
evolvingthoughts | March 14, 2008
Jon is a Utah biologist. His talk is on population genetics.
He is talking about an unusually clean evolutionary experiment that leaves natural populations just as messy as they were before. Real populations are so complicated they frustrate basic models and general principles of population genetics. The whale lice of right whales are the case study used. The speciated about 5 million years ago and have distinct habitats.[Coalescent theory has completely changed how we do this work.]
Okay: species are communities of genes, he says. Various problems - ring species, clines, yadda yadda. […
evolvingthoughts | March 14, 2008
This is a session on paleontology that I missed the start of because I had to go get my power supply.
Julia, a paleontologist, is discussing the evolution of birds, and how paleontology was misled by hypotheses that used the wrong taxa and characters. I'd love to blog it more extensively, but I missed the start.
She is noting the telic nature of some hypotheses, and how she and her colleagues worked in a different way, phylogenetically. Adopting a method used in molecular phylogeny, they supposed that character states might be decomposeable into smaller subregions, anatomically. They…
evolvingthoughts | March 14, 2008
Jay is an ecological philosopher. He wants to sketch how ecologists have used boundaries, and outline both a skepticism and an interactive approach.
He's not talking about types of ecosystems but tokens; not biomes, for example. Second, some ecosystems are sociopolitical objects (Greater Yellowstone).
In 1935, A. G. Tansley distinguished ecosystems - the abiotic and biotic resources - and rejected communities - set of interacting species. Ecosystem ecology focused on the flow of nutrients and energy through organisms and their environments. Organisms are transducers of energy and…
evolvingthoughts | March 14, 2008
Lunch being had we crowd into a new room to hear Stephen Peck, a biologist from Brigham Young University down the road a ways in Provo. Stephen is talking about ecological boundaries.
A group of ecologists set up seven different ecosystem groups for agroecosystem studies. They debated how to define an ecosystem, and it simply got harder. They needed a biological indicator to determine the state of the ecosystem and couldn't even get to defining the latter. Over fifteen years, he hasn't been able to figure it out.
Properties of ecosystem boundaries:
Fuzzy
Non-regulated -> Highly…
evolvingthoughts | March 14, 2008
Bill Wimsatt is somewhat of a hero around here and for good reason. He is perhaps one of the most influential under-published philosophers of biology. Today he's talking about modularity in biological and cultural evolution.
Modularity is a recurrent theme in biology and culture. Evolved systems are usually modular. It's easier to make a modular system, because there are fewer part types - polyfunctional parts.
They are easier to modify if you can adapt to local circumstances by changing one or a few parts rather than the whole system. Quasi-independent parts
A small number of parts…
evolvingthoughts | March 14, 2008
Jim Griesemer is one of my favourite philosophers. Here he's discussing the work of Herbert Simon on dynamical boundaries.
What Simon said was that subsystems are nearly decomposable - systems are hierarchical and their internal relations are stronger than their cross level relations - and that this is a criterion for the dynamic specification of such systems.
He discusses the Hora and Tempus example. Jim asks, how do either of them make watches at all? He asserts that scaffolding - any structure or element that facilitates the development of a system's skills or capacities - is…
evolvingthoughts | March 14, 2008
Monica Piotrowski (Utah) also is talking about DNA Barcoding. She starts with a child's coin sorter. Imagine that it's a bug-sorter, sorting by DNA samples. What does the child now have? She claims Barcoders must have a species concept to measure the success of their practice. They have none, and so they are in a two-horned dilemma neither option of which is a good option.
COI is claimed to be 99.75% identical within, and <97.5% between species. Hence it can delimit, but not describe, species, according to Hebert and Strauss, the founders and promoters of Barcoding. So, what's the…
evolvingthoughts | March 14, 2008
Brent Mishler is a very nice guy who is wrong on a few things - Phylocode, species, and so on - but he's absolutely right about barcoding. He's talking today about so-called DNA barcoding and species concepts.
He says that species are just the least inclusive taxa for whatever view of taxa one has - there is no species problem per se.
He thinks that species are just the smallest monophyletic group worth diagnosing. And more: since biology should be free of taxonomic ranks, species (as a rank) should be dropped. I can agree or not depending on what interpretation is given here. Brent…
loom | March 14, 2008Science writer Edmund Blair Bolles is in Barcelona at the Evolution of Language conference, and he's live-blogging like crazy. Fascinating stuff well worth checking out. [Link fixed-cz]
evolvingthoughts | March 13, 2008
I have just sat through one of the most teeth clenchingly bad philosophy talks, given on phylogenetics by a philosopher who has never read anything sensible on phylogenetics to phylogenetic systematists. One of the last mentioned leant over to me and asked "Does this guy know anything?" I had to say no. I am protecting the guilty for reasons of manners, but people: If you are going to lecture professionals about what they do as a philosopher, at least try to learn the science first. Whatever you do, don't think that because you've read a book by a critic of the topic that you understand the…
gregladen | March 12, 2008Charles Darwin turns 200 next year--Happy birthday, dude!--and the Peabody Museum of Natural History is getting excited. You would think that a couple centuries would have kicked the last bit of dust over the grave of "intelligent design," but sadly, it ain't so. The people at the Peabody still have some convincing to do, and that's where Travels in the Great Tree of Life, a multimedia exhibit curated by evolutionary biologist, Yale professor and Peabody Director Michael Donoghue, comes in. ...
[Read the rest here]
mikethemadbiologist | March 12, 2008I've written before about CTX-M-15 beta-lactamases which make bacteria resistant to most cephalosporin antibiotics--those antibiotics that begin with cef- (or ceph-) or end with -cillin. I've also discussed the role of clonal spread in the rise of antibiotic resistance: most (but obviously not all) resistant infections are not the result of a sensitive strain evolving resistance during the course of infections, but rather due to colonization by a previously resistant strain. A recent article in Emerging Infectious Diseases discusses the role of clonal spread in the dissemination of CTX-M-…
razib | March 11, 2008You've probably heard about this story. Check out Afarensis and Anthropology.net for a summary of the science. But Kambiz also has some juicy gossip about the back-story here....
oracknows | March 11, 2008You may remember from yesterday that I wrote about a concerted propaganda effort by antivaccinationists to torture the facts and science behind a case of a girl with a rare mitochondrial disease whose condition may have been exacerbated by vaccination, resulting in an encephalopathy with some autism-like symptoms. Actually, I had had in mind an entirely different topic for yesterday, but news events drove me. Basically, I couldn't stand all the B.S. I saw emanating from antivaccinationists on news broadcasts and radio, and I had to do my little part to counter it. Fortunately (or…
evolvingthoughts | March 10, 2008
John Lynch took me to the Arizona-Sonora Desert Museum yesterday, and made me walk. Naturally I forgot my camera, so I can't show you the really cool hummingbirds, or the cougar/puma (it has a split personality) or the bighorn sheep, let alone the amazing diversity of plant life (until I came here I though "cactus" was a single species - just kidding), but you can see all that at the Museum's website and digital library.
I forgive John for making me walk - he was not to know that silverbacks, especially albino silverbacks, are lazy fat buggers. But the provision of ice cream and slushy…
edyong | March 10, 2008
The story of evolution is filled with antagonists, be they predators and prey, hosts and parasites, or males and females. These conflicts of interest provide the fuel for 'evolutionary arms races' - cycles of adaptation and counter-adaptation where any advantage gained by one side is rapidly neutralised by a counter-measure from the other. As the Red Queen of Lewis Carroll's Through the Looking Glass said to Alice, "It takes all the running you can do, to keep in the same place."
The Red Queen analogy paints a picture of natural foes, wielding perfectly balanced armaments and caught in a…