These are papers that may be of general interest published this week, with commentary as necessary. No specific case studies, overly specialised research, or taxonomic papers. Papers ordered only by their appearance in my inbox. For PDFs, e-mail me, I get most of them. You can request an in-depth analysis of any paper and I’ll do it as I get the time.
Open-access papers, those that are free to read/download even without an academic connection, are tagged with [OA] for easy finding with your browser’s text search (Ctrl+F).
12 papers this week, 4 of them open access.
New Books in the Store:
Special Issues:
“Evolutionary rescue” happens when a population or species becomes adapted to environments which are lethal to its ancestors. This special issue is full of case studies and examinations of the phenomenon from a theoretical level, so worth reading if this interests you. Schiffer et al. is the only [OA] paper, luckily it’s one of the more interesting ones.
An amazing special issue on one of the coolest phenomena in biology, one which I’ve written about before: parasites that take over and manipulate their hosts’ behaviour. All the papers here are excellent reviews.
If you’re even remotely interested in human evolution, get the papers from this special issue. They cover everything, from development in hominins to morphology to brain to language and ecology. Very highly recommended.
Botany:
Given just how dependent on physical factors plant development is, it’s no wonder that they develop somewhat differently in space with no gravity. This research is cool because it allows us to narrow down exactly what is gravbity-dependent and what isn’t. Besides this, it’s also useful in case we ever get around to establishing space colonies or something.
Evolution:
An introduction to caves as ideal nmatural arenas for evolution isn’t needed. This paper demonstrates that in caves, evolution will be canalised to form distinct morphological classes, and that the emergence of these classes is dependent on the cave habitat to which a species is adapting. That this happens for the entire community is the remarkable result, meaning that these morphologies are ecomorphs, not just specific adaptations. Of course, this study was only done with one genus, but the same result being found with a broader taxonomic study wouldn’t surprise me.
This is what I would love to do if I had money and a lab.
History:
This is an excellent look at the history of ideas about speciation, and also serves as a glossary/dictionary. Worth keeping just as a reference.
Microbiology:
This is of interest for those who are into endosymbiosis.
Palaeontology:
Amazing find that will require me to update my stock history of life lecture, specifically the part that says that the only mammals that survived past the KT event were marsupials and placentals. This Miocene fossil is a mammal and is neither a marsupial nor a placental. Okay, I’m overblowing it a bit, since apparently this has been known for a bit, but it’s the first I’ve heard of it (and I consider myself as keeping abreast of the literature). So, still spectacular.
This is significant for those interested in the evolution of birds.
Here, we redescribe the wings of the archaic bird Archaeopteryx lithographica and the dinosaur Anchiornis huxleyi and show that their wings differ from those of Neornithes in being composed of multiple layers of feathers. In Archaeopteryx, primaries are overlapped by long dorsal and ventral coverts. Anchiornis has a similar configuration but is more primitive in having short, slender, symmetrical remiges. Archaeopteryx and Anchiornis therefore appear to represent early experiments in the evolution of the wing. This primitive configuration has important functional implications: although the slender feather shafts of Archaeopteryx and Anchiornis make individual feathers weak, layering of the wing feathers may have produced a strong airfoil. Furthermore, the layered arrangement may have prevented the feathers from forming a slotted tip or separating to reduce drag on the upstroke. The wings of early birds therefore may have lacked the range of functions seen in Neornithes, limiting their flight ability.
Phylogenetics:
It never ceases to surprise me that this isn’t straightforward and clear. Remember: fossils provide the only tangible evidence for how traits evolved. They’re the baseline information against which everything else must be checked for validity.
Zoology:
In zoology, “gordian knot” refers to an aggregation of mating nematomorphs (hairworms) – the normally free-living aquatic organisms gather into a tight ball, imaginarily reminiscent of Midas’s legendary knot. This study looked at what exactly happens in these Gordian knots. I was surprised that the knots are first composed entirely of males, with females getting in the mix later.
I mentioned chemosynthesis in the deep sea in two of my deep sea posts. This paper is a thorough review, concentrating on those organisms that can survive solely by chemosynthesis and not rely indirectly on photosynthetic products, like oxygen or marine snow.
This paper has a ton of coauthors and it’s not a genomic paper? Expectations are automatically raised then. And it doesn’t fail – it serves as a standard reference for how many marine species have been described so far. I will need to read the statistics for how many exist in total more carefully as I’m a bit skeptical of the number they predict (0.7 – 1 million) – it seems rather low to me. Still, get it if you’re interested in biodiversity.
The neural crest has long been considered the key innovation that allowed vertebrates to achieve their evolutionary success. Some authors even go as far as treating it as a fourth germ layer. Basically, the neural crest is a dorsal fold of the neural tube from which a population of migratory multipotent cells is derived. These migrate along specific pathways to form, among other things: the skull and face, teeth, a lot of the heart and circulatory vessels, pigment cells, the spinal column and the peripheral nervous system, and the thyroid and adrenal glands.It’s also long been known that its evolution was not a spontaneous one, but that glimmers of it can be seen in other chordates. This paper is significant in that it identifies more than “glimmers”: it identifies a full-fledged neural crest in a tunicate.
