I only just found out that Jerry Fodor recently debated Philip Kitcher on the merits of Darwinism, specifically the value of natural selection in an explanatory capacity. While Fodor is an avowed atheist and metaphysical naturalist, he nevertheless takes a very dim view of Darwinism (though not evolution or common descent), and I tend to find his views interesting for one reason only: His ability to really, really irritate a diverse array of people.

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I've been reading Kirschner and Gerhart's The Plausibility of Life, which so far is a fascinating read. I'm not done, but it appears that their view is that there have been sudden appearances throughout natural history of "core processes" in living organisms, which then allow the organisms to evolve by relatively small, simple steps. But what they haven't done, so far, is explain where these core processes come from. Perhaps they will offer an explanation later in the book.
But you think they would offer at least a passing mention of Lynn Margulis's ideas of endosymbiosis and symbiogenesis. She knew about the sudden appearances of core processes, and suggested that they came about by acquiring the genomes of other organisms. This happened, according to her view, by either bacteria or protists engulfing other bacteria (endosymbiosis), or more recently, by multi-cellular organisms being infected by bacteria or viruses (symbiogenesis). Read the rest of this entry »

Today's New York Times carries a story in its 'science' section by Carol Kaesuk Yoon entitled From a Few Genes, Life's Myriad Shapes.

It's a story about Evo-Devo, with strong allusions to what we are familiar with around TT as Front-Loading. Some pertinent quotes from the article seem to speak obliquely to challenges Evo-Devo has presented to the standard Neo-Darwinian story line since it took off in the 1980s, a clear indication that it can take decades for new ideas and new evidence to rise to a level where the implications are marketed to a public universally taught the standard RM-NS pablum that still maintains its hegemony in public education by force of law…

…the advent of molecular biology reinvigorated the study of development in the 1980s, and evo-devo quickly got scientists' attention when early breakthroughs revealed that the same master genes were laying out fundamental body plans and parts across the animal kingdom. For example, researchers discovered that genes in the Pax6 family could switch on the development of eyes in animals as different as flies and people. More recent work has begun looking beyond the body's basic building blocks to reveal how changes in development have resulted in some of the world's most celebrated of evolutionary events.

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As long as we're on the subject of grandmas, I wanted to bring up an interesting, but poorly understood, biological phenomenon. Genetic information inherited from a specific parent may be "hidden" (through gene silencing), but over a number of generations, the information may contribute to the phenotype of the group. This is known as genomic imprinting. This and other kinds of examples related to genomic imprinting, such as transgenerational epigenetic inheritance, may even explain what occured here

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Lizard Wizard Johnathan B. Losos, lately of Harvard University, has released results of a very interesting experiment on lizards inhabiting small cays in the Bahamas showing surprisingly rapid evolution – like, within a single generation – via the introduction of a new predator.

In order to appreciate the details, a little background on previous findings is warranted. Losos revealed in 1998 that Caribbean Lizards Evolve Independently on separate islands, despite an end result that shows very similar morphology and behavior. In evolutionary terms, this is known as "convergence."

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Chordates may have started with this little eel-like critter, known as Pikaia, but today spans a diverse range of animals, such as mammals, birds, and fish. In a surprising discovery, a group of researchers have found that some of the signalling machinery used by chordates dates far further back.

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This is a thread about nothing, and therefore everything. In case you don't know what to talk about, here's some links a couple of months old – by blogosphere standards, an eternity.

Wesley J. Smith writes about the PETA, who "liberates" animals from a life with humans – by killing them and leaving their bodies in a dumpster.

Joe Carter writes about "the theocracy canard", the belief that the US is turning into a theocracy. Although Jonathan Rowe agrees with Carter that much of the theocracy rhetoric is overblown, he still takes exception to some of his claims. For more about the interplay between church and politics, check out what Timothy Goddard has to say.

Finally, in The New York Review of Books, a triple-review of books on evo-devo, challenging and revising the traditional Neo-Darwinian synthesis.

Have something you want to share? Do it here. Some thematically related suggestions for discussion:

Evolution News & Views points to an article in The Chronicle on Higher Education (registration required) on the case of Francis Beckwith, the pro-life and ID-friendly philosopher who had tenure denied to him at Baylor. From the article:

C. Stephen Evans, a professor of philosophy and humanities, says he will consider resigning if the decision is not reversed. Mr. Evans, who calls himself a liberal democrat, says Mr. Beckwith is being "railroaded for his conservative views, even though he clearly merits tenure on the basis of his scholarly work and teaching."

Denyse O'Leary of Post-Darwinist doesn't support attempts to mess with the science classes of high schoolers, because she believes that students should earn the right to dissent from their teachers' views.

To those of you taking Front-Loaded Evolution 101, here's a little thing that might be on the exam:

In the September 12 issue of the journal Public Library of Science Biology, the researchers report that in both fruit fly and chick embryos proteins called BMPs play similar roles in telling cells in the early embryo to switch certain genes on and off, specifying the identity of the cells making up the three primary subdivisions of the central nervous system. The findings suggest a unified model of early neural development in which at least part of the mechanism for creating neural patterning has been preserved from a shared ancestral organism that lived over 500 million years ago.
"Mechanism to Organize Nervous System Conserved in Evolution"

Another open thread for you to roam around in. Some stray thoughts:

A while ago, it was announced that the Flores people, also known as hobbits, discovered in 2004, "do not represent a new species as then claimed, but some of the ancestors of modern human pygmies who live on the island today", and that their exceptional small brain size was due to birth defects in one of the individuals. The paper arguing this is freely available, and anthropologist John Hawks has a good summary of the research.

The New York Review of Books reviews three new books about the "discoveries [that] have radically altered our views of evolution and of the relation of human beings to all other animals." One of the books is Sean Carroll's Endless Forms Most Beautiful, which I've written about here, while another is Kirschner's and Gerhart's The Plausibility of Life, which I've quoted from here and here.

Intelligent design is often described as an insidious creationist plot. In what can only be a perplexing paradox, some creationists actually criticize intelligent design, like Carl Wieland from Answers in Genesis. Over at WithAllYourMind.net, Barry is planning a series of post responding to those criticisms. The first installment can be read here.

The other day, I lamented the fact that I dont write more about front-loading, the idea that the designer made the first organisms with the future in mind, and that the original design influenced the course of evolution. So, to make up for it, here's some news about everyone's favorite topic.

Front-loading: Developmental biologist PZ Myers writes about research, showing that much of the complexity of modern organisms arose much earlier thanhas previously been suspected:

The most important message, though, is that the morphological complexity of modern bilaterians has molecular antecedents in seemingly simple organisms. It suggests that the cnidarian ancestor might well have been bilaterally symmetrical, and that the apparent simplicity of modern jellyfish and anemones may be the product of a loss of bilaterality, meaning that the basic regulatory interactions that define asymmetry in animals may have a greater antiquity than we usually think.

I told you so.

Front-loading: In case you haven't noticed it, my fellow Telician Mike Gene is writing a book, and his new blog The Design Matrix is dedicated to scientific discoveries that are relevant to the book. In the post, "Extending the Reach of Front-Loading", he considers the possibility that the development of eco-systems are front-loaded.

And more front-loading: From "Building divergent body plans with similar genetic pathways", in the journal Heredity:

Many genes that are considered vertebrate 'mesodermal' genes, such as nodal and brachyury T, are likely to ancestrally have been involved in the formation of the mouth and anus, and later were evolutionarily co-opted into mesoderm during vertebrate development.

On Telic Thoughts, we like to focus on aspects of life and evolution that help us see evolution as something that may be more interesting than conventional neo-Darwinian explanations would have us expect. But it looks like good old-fashioned, Darwinian gradualism may have played the crucial role in whale evolution:

the gradual shrinkage of the whales' hind limbs over 15 million years was the result of slowly accumulated genetic changes that influenced the size of the limbs and that these changes happened sometime late in development, during the fetal period.

Relying on anatomical data, the researchers argue that Sonic hedgehog (a crucial gene in limb development) was inactivated late in whale evolution.

On the other hand, another report on the same study tells us that taking Sonic hedgehog offline early on seems to have been the key event in dolphin evolution.

Critics of Neo-Darwinism are often admonished to remember the research it has inspired and the fulfilled predictions it has made. However, such advise wouldn't be entirely fair unless we were also asked to remember the cases where Neo-Darwinism has bet on the losing horse. So, without further ado, here is Ernst Mayr, one of the major architects of the Neo-Darwinian synthesis, on the hopeless prospects of finding "deep homology":

Much that has been learned about gene physiology makes it evident that the search for homologous genes is quite futile except in very close relatives. If there is only one efficient solution for a certain functional demand, very different gene complexes will come up with the same solution, no matter how different the pathway by which it is achieved. The saying "Many roads lead to Rome" is as true in evolution as in daily affairs.
Ernst Mayr, Animal Species and Evolution (Harvard University Press, 1963), p. 609

Mayr's theoretical argument is hard to gainsay, but unfortunately, reality refused to butt. One of the great suprises of evo-devo was the discovery that hox genes, which are used to construct structures such as limbs and eyes, are shared between mice and flies, the common ancestor of which lived 600 million years ago. Interested readers are invited to check out my old post on this subject, titled "Carroll and the ancient genetic tool kit".