Interesting Science Stuff

Something that will make the creationists and ID types sad. Here is the abstract:

Vestigial structures occur at both the anatomical and molecular levels, but studies documenting the co-occurrence of morphological degeneration in the fossil record and molecular decay in the genome are rare. Here, we use morphology, the fossil record, and phylogenetics to predict the occurrence of “molecular fossils” of the enamelin (ENAM) gene in four different orders of placental mammals (Tubulidentata, Pholidota, Cetacea, Xenarthra) with toothless and/or enamelless taxa. Our results support the “molecular fossil” hypothesis and demonstrate the occurrence of frameshift mutations and/or stop codons in all toothless and enamelless taxa. We then use a novel method based on selection intensity estimates for codons (ω) to calculate the timing of iterated enamel loss in the fossil record of aardvarks and pangolins, and further show that the molecular evolutionary history of ENAM predicts the occurrence of enamel in basal representatives of Xenarthra (sloths, anteaters, armadillos) even though frameshift mutations are ubiquitous in ENAM sequences of living xenarthrans. The molecular decay of ENAM parallels the morphological degeneration of enamel in the fossil record of placental mammals and provides manifest evidence for the predictive power of Darwin’s theory.

I’ll have more to say about it later.

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Interesting Anthropology and Science News

There are several interesting items on Science Daily.

First, Monkeys Get A Groove On, But Only To Monkey Music:

The similarities in communications between monkeys and people suggest deep evolutionary roots for the musical elements of speech, Snowdon says. “The emotional components of music and animal calls might be very similar, and from an evolutionary perspective, we are finding that the note patterns, dissonance and timing are important for communicating affective states in both animals and
people.”

You can hear samples of the music here.
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Interesting Anthropology and Paleontology News

There is some interesting news relating to anthropology and evolution – over and above Darwinius masillae (which I will have a couple of posts about next week). Continue reading

Do Deep Sea Fish Have Good Hearing?

An interesting article over at National Geographic looks at that question:

Roughly 90 percent of the ocean is completely dark, beyond the reach of the sun’s rays.

The researchers wondered if the fish had evolved to have sharper hearing, which might help them catch prey, find mates, or elude predators in the darkness.

The researchers were looking at fish that lived in waters as deep as 1.6 miles. What they found was interesting:

The inner ear (pictured) of a blue antimora (inset) is exceptionally rigid—a feature never before seen in a deep-sea fish, according to a study to be presented in May 2009.
Photograph courtesy Xiaohong Deng et al.; inset photograph courtesy NOAA

A couple of things stand out in the National Geographic article. First, the ears were compared to those of surface dwelling fish and were found to have long rods attached to their ototliths:

“We do not quite know what [the stalks’] function is yet,” said study co-author Xiaohong Deng, a marine biologist at the University of Maryland.

But Deng suspects these stalks allow the otoliths to register sounds that would otherwise be too faint to hear.

The ridgehead ears’ also had very long hair bundles—features also seen in the ears of shallow-water species known to have great hearing, such as the pinecone soldierfish and clown knife fish. The bundles may enhance the fish’s sensitivity to sound and to their own head motion, which would improve the fish equivalent of balance, Deng said.

Second, a second species had rigid inner ears similar to that found in bluefin tuna. The close proximity of the swim bladder – an organ that controls buoyancy and amplifies sound – strengthens the suggestion. What this says to me is that evolution has found multiple ways of dealing with darkness. It also indicates that the affects of selection on the swim bladder, or for better hearing, are likely to have unintended consequences…

Interesting Evolution News

There are a number of interesting pieces of evolutionary research in the news. Some are a little on the old side…

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Interesting Evolutionary Research

There are are couple of interesting pieces of research in the news. The first concerns tail shedding in island lizards. PhysOrg has the story:

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NCSE On YouTube!

The National Center for Science Education has a YouTube Channel!

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