evolution
razib | November 17, 2008Richard Lawler pointed me to a new paper by Sean Rice, A stochastic version of the Price equation reveals the interplay of deterministic and stochastic processes in evolution. The Price Equation is the generalization of selective evolutionary dynamics by the amateur evolutionary biologist George Price which so impressed W. D. Hamilton. But as Rice notes it only captures a slice of the various parameters which influence evolutionary processes. Like some other papers I've pointed too Rice presents some relatively counter-intuitive results, or at least results which confound our general…
razib | November 17, 2008Ancient DNA, Strontium isotopes, and osteological analyses shed light on social and kinship organization of the Later Stone Age:
In 2005 four outstanding multiple burials were discovered near Eulau, Germany. The 4,600-year-old graves contained groups of adults and children buried facing each other. Skeletal and artifactual evidence and the simultaneous interment of the individuals suggest the supposed families fell victim to a violent event. In a multidisciplinary approach, archaeological, anthropological, geochemical (radiogenic isotopes), and molecular genetic (ancient DNA) methods were…
laelaps | November 17, 2008
"The Young Monkey," from Funny People, or the True Origin of Species
When I refer to a book with the phrase Origin of Species in the title, it is generally understood that I am talking about the volume by Charles Darwin, published in 1859, that was so important that we are still avidly discussing it almost 150 years after it was published. Like any popular hit, however, there were other tomes that tried to capitalize on the fame of On the Origin of Species by Means of Natural Selection.
Earlier this year I mentioned one such title; a print version of some of T.H. Huxley's popular lectures…
pharyngula | November 16, 2008Here's another youtube bandwagon to jump on: I Am Darwin. Get in front of your webcam and talk about how Darwin has influenced you, concluding with "I am Darwin", and send the youtube link to Tom Barbalet. How many Darwins are out there, anyway?
laelaps | November 16, 2008During the past few weeks I have tried to step back from adding new material to my book to gain a better perspective on how I'm telling the story I want to convey. Much of what I'm writing concerns recent discoveries to explain how we know what we say we know about evolution, but the framework from which all that hangs is a combination of historical and scientific narrative.
Nowhere is it more important to be conscious of this than in the chapter on human evolution. I have done my best to avoid illustrating evolution as development towards a given point, that our species in particular was…
grrlscientist | November 16, 2008tags: Birdbooker Report, bird books, animal books, natural history books, ecology books
"One cannot have too many good bird books"
--Ralph Hoffmann, Birds of the Pacific States (1927).
The Birdbooker Report is a special weekly report of a wide variety of science, nature and behavior books that currently are, or soon will be available for purchase. This report is written by one of my Seattle birding pals and book collector, Ian "Birdbooker" Paulsen, and is edited by me and published here for your information and enjoyment. Below the fold is this week's issue of The Birdbooker Report which…
evolvingthoughts | November 14, 2008
As I have argued before, there is a class of objects in the biological domain that do not derive from the theory of that domain, but which are in fact the special objects of the domain that call for a theoretical explanation. The example I have given is mountain, which is a phenomenal object of geology, and yet not required by the ontology of any geological theory, which does include overfolds, tectonic plates, upthrusts, the process of differential erosion, and so on. At the end of the theoretical explanation, the mountains have not disappeared so that we might now drive from Arizona to Los…
gregladen | November 14, 2008The paper I'm about to discuss is a minefield of potential misconceptions that arise from the way we often use language do describe natural phenomena. This is a situation where it would be easier to start with a disclaimer ... a big giant obvious quotation mark ... and then use the usual misleading, often anthropomorphic language. But I don't think I should do that. We'll address this research the hard way, but the result will be worth the extra work.
Here is the basic hypothesis. The null model is that genetic variation arises randomly and this variation is the raw material on which…
clock | November 14, 2008Go here (requires a 5-second process of signing up for FriendFeed, a move you will not regret, if you want to comment instead of just reading) and participate in liveblogging as the Beagle Project crew visits the opening of the Darwin exhibition.
edyong | November 14, 2008When we think about cooperative behaviour, most of us would think of animals like ants, meerkats, lions or, indeed, humans. But don't rule out yeast. The small, single-celled fungus has provided us with much of our knowledge of genetics and molecular biology and now, it's shedding light on the evolution of cooperation too.
The budding yeast, Saccharomyces cerevisiae, is one of the most widely studied of laboratory microbes, but scientists mostly know it as a solitary species. Brewers, on the other hand, use S.cerevisiae to make beer and are all too aware of its social side. Their strains…
awild | November 13, 2008
Atta cephalotes carrying leaves, Ecuador
Molecular Phylogenetics and Evolution this morning has the first detailed molecular phylogeny of the leafcutting ant genus Atta. MaurÃcio Bacci et al sequenced several mitochondrial genes and the nuclear gene EF-1a from 13 of the 15 described species-level taxa, using them to infer the evolutionary history of the genus.
This is an important paper.Â
Atta is the classic leafcutter ant of the new world tropics and a model system for co-evolution among the ants, the fungi they cultivate, and a suite of microbes that either parasitize or protect the…
gregladen | November 13, 2008In 1953 a student named Stanley Miller did an experiment showing that the simple chemicals present on the early Earth could give rise to the basic building blocks of life. Miller filled a flask with water, methane, hydrogen and ammonia--the main ingredients in the primordial soup. Then he zapped the brew with electricity to simulate lightning, and, voila, he created amino acids, crucial for life. Now, scientists have reanalyzed this classic experiment, and found that the results were even more remarkable than Miller had realized.
Jeffrey Bada, a former student of Miller's, preserved the…
oracknows | November 13, 2008
The things I do for my readers.
I'm referring to a movie entitled The Beautiful Truth, links to whose website and trailers several of you have e-mailed to me over the last couple of weeks. Maybe it's because the movie is only showing in New York and Los Angeles and hasn't made it out of the media enclaves of those cities out to the rest of us in flyover country, or maybe its release is so limited that I just hadn't heard of it. Certainly that appears to be the case, as the schedule shown at the website lists it as beginning an engagement in New York tomorrow and running through November 20…
evolvingthoughts | November 12, 2008
So wrote the renaissance humanist, Erasmus of Rotterdam: Man is to man either a god or a wolf. Here, courtesy of Leiter, is an article in The Telegraph, in which philosopher Mark Rowlands describes his life with a wolf, and how he ended up learning, as he puts it, how to be a human from the wolf.
Few animals are as similar in their social behaviour to humans as wolves. The domesticated dog is subordinated to human breeding goals, but the wild wolf is itself - a pack animal with dominance psychology, capable of identifying intentions in other agents, of exploring, teaching and playing. And…
edyong | November 12, 2008
Hair, or fur, is one of the hallmarks of mammals, the group of animals to which we belong. It is an evolutionary innovation that provides us with protection and helps us to maintain our constant body temperature And while hair is a uniquely mammalian feature, its genetic building blocks are anything but. A new study has found that genes responsible for building the locks on your head have counterparts that construct the claws of lizards.
Hair is made of proteins called keratins, which interact with each other to form long, hard filaments. Keratins are widespread in the animal world but…
grrlscientist | November 12, 2008tags: ecology, exotic species, introduced species, non-native species, invasive species, monk parakeets, quaker parrots, Myiopsitta monachus, Michael A Russello, Michael L Avery, Timothy F Wright
Monk (Quaker) parakeets, Myiopsitta monachus, with nest.
Image: Arthur Grosset [larger view].
Invasive species are everywhere: from plants such as Scotch (English) broom, Cytisus scoparius, whose yellow flowers bloom prolifically along roadways of North America, Australia and New Zealand to mammals such as human beings, Homo sapiens, which are the ultimate invasive species because we have…
pharyngula | November 12, 2008There is a maddeningly vague press release floating around, and I think everybody has sent me a link to it now. It contains a claim by some chemists that they have discovered a new organizing principle in evolution.
A team of Princeton University scientists has discovered that chains of proteins found in most living organisms act like adaptive machines, possessing the ability to control their own evolution.
The research, which appears to offer evidence of a hidden mechanism guiding the way biological organisms respond to the forces of natural selection, provides a new perspective on…
gregladen | November 12, 2008It is hard to kill fungus. Well, not really. They can't handle being burned and chlorine does them in and lots of other chemicals are bad for hem. But when a fungus infects a person ... like with Aspergillos, an infection with Aspergillus in the lungs, fungi are tricky. To kill an infectious agent, one typically poisons it somehow, but to ingest, inject, inhale, or even topically apply a chemical may also affect the person. The reason it is relatively easy to kill an infecting bacterium than it is to kill an infecting fungus is, in part, because fungi are phylogenetically more closely…
evolvingthoughts | November 11, 2008
There have been several attempts to produce an ontology of biology and the life sciences in general. One of the more outstanding was Joseph Woodger's 1937 The Axiomatic Method in Biology, which was based on Russell's and Whitehead's Principia and the theory of types. In this, Woodger attempted to develop a logic system that would account for all the objects of the theories of biology, especially of embryology, physiology (including cell theory) and genetics. It was hard going even for logicians (Tarski himself wrote an appendix), and the theory thus elucidated seemed to be very post hoc - it…
laelaps | November 11, 2008
Lately I have been a bit fixated on the arguments over evolution & creationism in America during the beginning of the 20th century (see here and here). As a result of further digging, I came across a few more resources that raise some interesting questions.
First is a short article from the Theological Monthly published in 1922. Entitled "Is Darwinism Still Popular?" the piece attacked scientists and members of the media who ridiculed folks like William Jennings Bryan for their belief in creationism. Much of it would sound awfully familiar to anyone acquainted with the present creation…