National Geographic mentions that a new species of moth sized bat has been discovered. Bat porn accompanies the article.
Filed under: Anthropology | Comments Off on Interesting Science – Mostly Anthropology – News
PhysOrg.Com has an interesting article by AP environmental reporter Michael Casey. The article, ostensibly about George Beccaloni’s quest to “return Wallace to what he sees as his rightful place in history.” The article recounts Beccaloni’s project to retrace Wallace’s trip through southeast Asia. An interesting moment in the article comes at the beginning when Beccaloni discovers the hut Wallace was staying in when he discovered natural selection. Unfortunately, almost from the beginning, the article credulously accepts creationist and Discovery Institute propaganda:
Connor MacLeod: How do you fight such a savage?
Ramirez: With heart, faith and steel. In the end there can be only one.
Rudolf Raff, in The Shape of Life, has an interesting discussion on attempts to iron out the relationships between lungfish, trout, and humans. On the surface it is quite simple. Lungfish are more closely related to humans than trout are. The lungfish has some adaptations to air breathing and one of the questions raised by the above relationship is whether these adaptations are homologous to those of tetrapods, or are they independent solutions to the same problem.
Enter the coelacanth. Morphological analyses of where the coelacanth fit into the above scheme yielded conflicting results as did various and sundry molecular analyses. One of the keys to solving the problem came in a mitochondrial DNA analysis that indicated a lungfish-tetrapod clade with coelacanths as the next branch and finally ray-finned fish. Assuming this is true, what can the fossil record and morphology tell us? This is where the story gets interesting. According to Raff, the lungfish, the coelacanth, and tetrapods are the few surviving members of a, once, more diverse rhipidistian clade. Early lungfish were deep sea forms that had gills, while modern forms are air breathers. Getting back to the question above, this means that the adaptations to air breathing are convergent with tetrapods. Raff concludes:
An especially striking demonstration of this conclusion is that the earliest know tetrapod, Acanthostega from the upper Devonian of Greenland has been shown by Coates and Clack to have had functional internal gills. It probably also possessed lungs, which were a primitive feature shared by bony fishes. Tetrapods have lost their gills in becoming more terrestrial. The first tetrapods thus convergently resembled modern lungfishes more than they resembled the earliest lungfishes. [page 162 – afarensis]
The molecular data wasn’t wrong, just incomplete due to missing taxa. In this case the taxa were missing due to extinction and this problem also, one thinks, affected the morphological analyses. I suspect that one could achieve the same affect by simply omitting some species from a morphological analysis. The point to take away from this is that in order to untangle the problem, both molecules and morphology were required. Not to mention more data. All to often, morphology and molecular analysis have been presented as being in some kind of zero sum conflict where there can be only one.
Update 1: Wesley Elsberry is also trying to win the trip.
As for me, I’ll be joining a contest where I win a free trip to someplace that will teach me how to spell and not make typos.