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).
13 papers this time, 5 open access.
Index:
- Special Issues [2]
- Arthropods [2]
- Developmental Biology [2]
- Ecology [2]
- Environmental [1]
- Evolution [1]
- History [1]
- Palaeontology [1]
- Zoology [3]
Special Issues:
- Impacts of global environmental change on drylands: from ecosystem structure and functioning to poverty alleviation.
- Biographical Memoirs of Fellows of the Royal Society 58.
It’s not really a special issue, but it’s best to classify any volume of this here. These are biographies of recently dead Royal Society members (“recently” measured in a timespan of years). Most interesting to me in this issue was Harry Whittington’s, the driving force behind the reinterpretation of Burgess Shale fossils in the 1970s and dead in 2010. Other biologists featured in this volume: Seymour Benzer (genetics); Tony James (biochemistry); Arthur Kornberg (biochemistry); Dan Lewis (botany); Iain MacIntyre (endocrine systems).
Arthropods:
- Brain anatomy in Diplura (Hexapoda). [OA]
- Neuroanatomy of Halobiotus crispae (Eutardigrada: Hypsibiidae): Tardigrade brain structure supports the clade Panarthropoda.
I’ve always supported a placing of the tardigrades as very close to the arthropods. Nice to see some more support.
Developmental Biology:
Gastrulation is the time of development when the germ layers are established. The majority of animals, excluding cnidarians and sponges, have three germ layers: endo-, ecto-, and mesoderm. Endoderm is responsible for things like the digestive system and lungs; ectoderm is responsible for the nervous system; and mesoderm for muscular and skeletal systems. This review outlines the steps that happen during gastrulation.
Because they’re immobile, plant physiology is fascinating – unlike animals, they have to face changing environmental conditions head-on, they can’t migrate or hide. They’re thus very flexible, with this flexibility caused by their continuously having populations of stem cells allowing plants to develop through their entire life cycle, as dictated by hormones. These hormones are reviewed in this paper. See Farnsworth (2004) for an ecological perspective.
Ecology:
- Phylogenetic constraints on ecosystem functioning.
- Ancient Origin of the Modern Deep-Sea Fauna. [OA]
I don’t quite agree with the conclusion of this paper, that deep sea habitats are evolutionarily stable. As I wrote in my deep sea posts, there is an equal amount of evidence suggesting that animals can recolonise the deep sea multiple times as environmental changes dictate. This doesn’t precluse some organisms truly being deep sea specialists though. In all, I would say that there is no generalisation.
Environmental:
Evolution:
Cave animals are some of the best examples to use of evolution. If you’re teaching evolution, get this paper for very thorough reviews of two cavernicolous model organisms, showing what happens to organisms when they’re left to evolve in the perpetual darkness of a cave: the fish Astyanax mexicanus and the isopod Asellus aquaticus.
History:
Those who’ve been reading the blog since the beginning will remember one of the earliest post series, on the planorbid snails of the Steinheim Basin (part 1 and part 2). I also mentioned the snails in my natural selection post. I really don’t know why Hilgendorf’s work is not more generally well-known – no popular evolution books mention them, to my knowledge, and it’s a shame because this isn’t only historically significant as the very first published evidence of gradual evolutionary transitions from only the fossil record and one of the first explicit phylogenetic hypotheses, but it’s a pretty good example of those too. I think one of the main reasons is that it’s from Germany; hopefully this paper will go some way to rectify the situation, providing a translation of Hilgendorf’s original dissertation as well as reviewing his corpus of related work.
Palaeontology:
The preservation here is stunning. Fuxianhuia is one of the more disputed arthropods of the early Cambrian due to its possession of “great appendages”, but making the “great appendage” arthropods paraphyletic. It’s classified as a stem-group euarthropod. Thus, the findings presented in this paper are very surprising: its brain shares many similarities with malacostracan brains, despite Fuxianhuia decisively not being a crustacean. It’s quite intriguing – not the fact that Fuxianhuia has a highly-developed brain (that’s a given), but the fact that the developments are so strikingly similar. To me, it means we have to be somewhat more careful with neurophylogenies – some characters may be very ancestral without our recognising them. I hope more stem-group arthropods get this same treatment (I can’t wait to see the brain of Anomalocaris).
Zoology:
Hapalochlaena lunulata is the greater blue-ringed octopus and the primary reason to not go swimming in Australia – it’s highly-poisonous and lives both in reefs, and shallow inlets and bays (i.e. no place is safe, although to be honest, they aren’t aggressive). The blue rings are chromatophore rings that are flashed as warning colouration, mostly to deter predators. They also flash them when feeding, after mating, and when under physiological stress. This paper describes the mechanism behind the flashing.
- Paths Less Traveled: Evo-Devo Approaches to Investigating Animal Morphological Evolution.
- What Is the Use of Elephant Hair? [OA]
Thermoregulation. Specifically, the hair helps them lose heat – a complete flip from the usual insulatory function of hair. Interesting stuff.
