Thursday, November 4, 2010

Massive random update

I've got a lot of junk on my computer's desktop that I have been intending to blog about, and I'm getting tired of the clutter. So today is "Fall Cleaning" day!

First up is a report from Lavoué et al. on extreme morphological stasis in African butterfly fish. This is sort of the inverse of adaptive radiation, where the morphology of a closely-related group of critters diverges rapidly. In the case of the African butterfly fish, they're all classed in the same species, but the mitochondrial DNA of fish from the Niger basin are 15% different from fish in the Congo basin. So they've diverged genetically quite a lot, but their appearance has hardly changed at all.

Lavoué et al. 2010. Remarkable morphological stasis in an extant vertebrate despite tens of millions of years of divergence. Proc R Soc B doi: 10.1098/rspb.2010.1639.

Next comes a report from Light et al. on the phylogeny of sucking lice. The only reason I'm interested in this is because of a passage from John Ray that I love to quote when talking about natural theology:
Here, by the by, I cannot but look upon the strange Instinct of this noisome and troublesome Creature the Louse ... as an Effect of Divine Providence, designed to deterr Men and Women from Sluttishness and Sordidness, and to provoke them to Cleanliness and Neatness.
Sucking lice: Designed or evolved? I think a lousy baraminology project would be fun.

Light et al. 2010. Evolutionary history of mammalian sucking lice (Phthiraptera: Anoplura). BMC Evol. Biol. 10:292.

I think among creationists, life cycles are generally thought to be pretty complicated things that probably aren't amenable to a lot of variation. At least that's what I think creationists would think if they expressed an opinion about life cycles. Thinking back over the history of creationist literature, I recall different papers using life cycles as evidence of design, so I'm going with the idea that creationists probably think that life cycles are mostly invariant. Enter certain aphid species with life cycles that alternate between woody and herbaceous plants, while other members of the same genus complete their entire life cycle on the same plant. Maybe life cycles aren't so invariant after all. Read all about it in Emmanuelle et al.'s phylogenetic study of these aphids:

Emmanuelle et al. 2010. Evolutionary lability of a complex life cycle in the aphid genus Brachycaudus. BMC Evol. Biol. 10:295.

About a month ago, Nature had a paper from Burke et al. on a long-term experiment studying the evolution of Drosophila fruit flies. From the abstract:
We conclude that, at least for life history characters such as development time, unconditionally advantageous alleles rarely arise, are associated with small net fitness gains or cannot fix because selection coefficients change over time.
This is a point I try to raise with creationists interested in whether or not there can ever be a "beneficial" mutation. Mutations are only beneficial in some environmental context. Intuitively, I never thought that something unconditionally beneficial could exist, especially in when the environment is liable to change. Read all about it:

Burke et al. 2010. Genome-wide analysis of a long-term evolution experiment with Drosophila. Nature 467:587-590.

Over at ARJ, Vardiman and Brewer have a new paper simulating precipitation with a warm ocean in the continuing quest to understand the environmental conditions in the first centuries after the Flood.

Vardiman and Brewer. 2010. Numerical Simulation of Precipitation in Yellowstone National Park with a Warm Ocean: Continuous Zonal Flow, Gulf of Alaska Low, and Plunging Western Low Case Studies. ARJ 3:209-266.

In the blogging world, Paul Garner has an interesting list of the top five challenges for creationist geology. And finally, Paul Nelson notes the passing of prominent evolutionary biologist Leigh Van Valen.

I am now caught up.

Feedback? Email me at toddcharleswood [at] gmail [dot] com.