Papers from this week. [OA] indicates open access, and all are discussable on request.
General Interest, Important:
After he came back from the Beagle voyage, Darwin never set foot on a boat again, and he became a sort of recluse, using a mysterious illness as an excuse to avoid excessive socialising. Opinion has generally been split between him suffering from Chagas Disease, or him merely being a hypochondriac. This paper proposes another hypothesis, that he was suffering from some sort of mitochondrial disease, based on analysis of his maternal family tree: several of his maternal family members died of mitochondrially-caused illnesses, so it was likely he had some sort of mitochondrial dysfunction as well.
I mentioned Osedax back in the very early history of the blog in one of the deep sea posts. They’re fascinating little creatures, a specialised genus from an already highly-specialised annelid family that lives only in extreme marine habitats, have no mouth gut, or anus: the Siboglinidae. They feed by having chemoautotrophic endosymbionts in them, with the only exception being Osedax, a genus first described only in 2004. The Osedax female burrows its hind end into bones that have fallen on the ocean floor, and then branches out into the bone, like a root system. Inside a special organ called the trophosome lie a bunch of gamma-proteobacterial endosymbionts which digest the bone and hand the nutrients off to the mothership. This paper greatly expands our knowledge of this system, by finding that the roots help the bacteria by mass-producing acid to help dissolve the bone, allowing the roots to spread further, and the bacteria to have easier access to bone.
Some more data on the plasticity of the human brain. It’s a pet topic of mine, since I often cross swords with people who think that intelligence is completely genetically hardwired into every individual human, thus throwing away everything we know about the evolutionary history of humans, all of social science, and quite a bit of evolutionary theory too.
I summerised what happened to vertebrates at the end-Triassic in a single slide in my Mesozoic Vertebrates lecture. All the Crurotarsi died out, except for one group, the crocodylomorphs. This paper provides a much higher resolution of what happened to the Crurotarsi. Yes, all but the crocodylomorphs got wiped out, but there was no significant shift in disparity – which means that the crocodylomorphs must have had an incredibly quick and effect adaptive radiation to replace all the other ecotypes.
- Production of chimeras between the Chinese soft-shelled turtle and Peking duck through transfer of early blastoderm cells.
Just something to freak out those who think that science has gone too far: turtleducks! Frankenstein’s Monster is just one day away! Okay, not really, there was no phenotypic change, but this is very cool nonetheless, showing that cells from two different classes can get developmentally integrated into the adult, at least in the case of duck cells in the adult turtle.
Bioinspired robotics are pretty awesome, and one of the best practical uses of zoology and especially entomology – the modular design of arthropods and insects is very conducive to engineering. I’ve written about insect flight and its complications here and here, and this paper demonstrates a robot that has replicated it. Impressive.
The molecular clock is another one of my pet topics, with my preferred scientific hobby being to shit on the majority of molecular clock studies. See my beef with it in this four-part series: 1, 2, 3, 4. This paper critically discusses molecular clock applications in insects.
The presence of silk-spinning spigots (see my spider lecture) on tarantula feet has been one of the recent controversies of tarantula biology. This could be the death knell for this story: tarantulas have weird stuff happening in their tarsi, but silk-spinning isn’t one of them.
- Misconceptions of sexual selection and species recognition: a response to Knell et al. and to Mendelson and Shaw.
A very interesting exchange happening in TrEE on how sound studies asserting the presence of fossil sexual selection and sexual dimorphism are. Be sure to read the replies by Knell et al. and Mendelson & Shaw. There are valid points raised by all parties.
Like any reasonable environmentalist, I’m a fan and supporter of increased nuclear power. Of course, the irrational public perception and fear of nuclear power is one of the larger impediments. The papers here are level-headed and show that nuclear power must be a key transitional power source to wean us off of fossil fuels. Read the rest of this entry »