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  Topic: Science Break, Selected Shorts< Next Oldest | Next Newest >  

Posts: 1002
Joined: Dec. 2006

(Permalink) Posted: July 22 2008,20:42   

Quote (Lou FCD @ July 22 2008,18:53)
I haven't located the original PNAS paper yet, but this movie was kind of cool.

The accompanying blurb, from LiveScience:

The Odorrana tormota frog opens and closes tubes in its ears when listening and calling at night. In this movie, the researchers shined a light under the frog's jaw to illuminate the inside of the mouth. The small circles of light on the side of the frog's head that brighten and dim show the opening and closing of the Eustachian tubes. Credit: National Academies of Science, PNAS (2008)

Yup, PNAS is bad about getting papers up on time. In the meantime, I have three that might be of interest (yes, I'm a literature hound)

The Ascent of the Abundant: How Mutational Networks Constrain Evolution:

Evolution by natural selection is fundamentally shaped by the fitness landscapes in which it occurs. Yet fitness landscapes are vast and complex, and thus we know relatively little about the long-range constraints they impose on evolutionary dynamics. Here, we exhaustively survey the structural landscapes of RNA molecules of lengths 12 to 18 nucleotides, and develop a network model to describe the relationship between sequence and structure. We find that phenotype abundance—the number of genotypes producing a particular phenotype—varies in a predictable manner and critically influences evolutionary dynamics. A study of naturally occurring functional RNA molecules using a new structural statistic suggests that these molecules are biased toward abundant phenotypes. This supports an “ascent of the abundant” hypothesis, in which evolution yields abundant phenotypes even when they are not the most fit.


Species richness and structure of three Neotropical bat assemblages:

We compared the assemblages of phyllostomid bats in three Neotropical rainforests with respect to species richness and assemblage structure and suggested a method to validate estimates of species richness for Neotropical bat assemblages based on mist-netting data. The fully inventoried bat assemblage at La Selva Biological Station (LS, 100 m elevation) in Costa Rica was used as a reference site to evaluate seven estimators of species richness. The Jackknife 2 method agreed best with the known bat species richness and thus was used to extrapolate species richness for an Amazonian bat assemblage (Tiputini Biodiversity Station; TBS, 200 m elevation) and an Andean premontane bat assemblage (Podocarpus National Park; BOM, 1000 m elevation) in Ecuador. Our results suggest that more than 100 bat species occur sympatrically at TBS and about 50 bat species coexist at BOM. TBS harbours one of the most species-rich bat assemblages known, including a highly diverse phyllostomid assemblage. Furthermore, we related assemblage structure to large-scale geographical patterns in floral diversity obtained from botanical literature. Assemblage structure of these three phyllostomid assemblages was influenced by differences in floral diversity at the three sites. At the Andean site, where understorey shrubs and epiphytes exhibit the highest diversity, the phyllostomid assemblage is mainly composed of understorey frugivores and nectarivorous species. By contrast, canopy frugivores are most abundant at the Amazonian site, coinciding with the high abundance of canopy fruiting trees. Assemblage patterns of other taxonomic groups also may reflect the geographical distribution patterns of floral elements in the Andean and Amazonian regions.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94, 617–629.


The origin of snakes (Serpentes) as seen through
eye anatomy

Snakes evolved from lizards but have dramatically different eyes. These differences are cited widely as compelling evidence that snakes had fossorial and nocturnal ancestors. Their eyes, however, also exhibit similarities to those of aquatic vertebrates. We used a comparative analysis of ophthalmic data among vertebrate taxa to evaluate alternative hypotheses concerning the ecological origin of the distinctive features of the eyes of snakes. In parsimony and phenetic analyses, eye and orbital characters retrieved groupings more consistent with ecological adaptation rather than accepted phylogenetic relationships. Fossorial lizards and mammals cluster together, whereas snakes are widely separated from these taxa and instead cluster with primitively aquatic vertebrates. This indicates that the eyes of snakes most closely resemble those of aquatic vertebrates, and suggests that the early evolution of snakes occurred in aquatic environments. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society,
2004, 81, 469–482.

Church burning ebola boy

FTK: I Didn't answer your questions because it beats the hell out of me.

PaV: I suppose for me to be pried away from what I do to focus long and hard on that particular problem would take, quite honestly, hundreds of thousands of dollars to begin to pique my interest.

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