lesliegliani: Most Interesting Papers of the Week ? Teaching Biology

মঙ্গলবার, ২৭ নভেম্বর, ২০১২

Most Interesting Papers of the Week ? Teaching Biology

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).

18 papers this week, 2 of them open access.

New Books in the Store:

Special Issues:

I was mostly interested in McInerny & Etienne.

All papers [OA]! I especially recommend Dunn et al. and Telfer & Bown.

Arthropods:

Every aphid species has special cells called bacteriocytes within which live symbiotic bacteria, Buchnera. This relationship has been around for ~250 million years, and is retained because it?s an obligate symbiosis for both the aphid and the bacterium, since neither can reproduce successfully without the other. This paper identifies just how deep the co-speciation has gone between these two is, with aphids generating completely new proteins to deal somehow with Buchnera:

We identified a novel class of genes that encode small proteins with signal peptides, which are often cysteine-rich, that are over-represented in bacteriocytes. These genes are first expressed at a developmental time point coincident with the incorporation of symbionts strictly in the cells that contribute to the bacteriocyte and this bacteriocyte-specific expression is maintained throughout the aphid?s life.

This is a thorough review of Mesozoic weevils. If you work with them, get it! For the basics of weevils, see my post.

Botany:

This review summarizes current knowledge about optimal defence patterns in above- and below-ground plant tissues, including information on basal and induced defence metabolite accumulation, defensive structures and their regulation by jasmonic acid (JA).

?Floral mimicry? refers to traits in flowers that allow them to attract insects by mimicking other flowers in either Batesian (mimic offers no nectar reward) or M?llerian (both flowers mimic each other, resulting in more flower visits to both) ways. This study shows which traits are most important for flowers to mimic, at least in orchids.

This study shows that traits that mimic, in order of importance, the spectra, shape and nectar guide patterns of flowers of rewarding plants would be under strong selection in food-deceptive orchids as they maximize attractiveness to their pollinators.

One of my pet peeves is the overreaction to wildfires, with people exclaiming that they?re disastrous to ecosystems. No, they?re not. Plants in wildfire-prone areas are adapted to seasonal fire, and adaptations to fire are ancient in many plants, as this paper demonstrates.

Focusing on the widespread 113-million-year-old family Proteaceae, fireproneness among Gondwanan Angiosperm floras can now be traced back almost 90 million years into the fiery Cretaceous. The associated evolution of on-plant (serotiny) and soil seed storage, and later ant dispersal, affirms them as ancient adaptations to fire among flowering plants.

Environmental:

A good meta-analysis on the topic.

We find 136 case studies of climatic impacts that are potentially relevant to this topic. However, only seven identified proximate causes of demonstrated local extinctions due to anthropogenic climate change. Among these seven studies, the proximate causes vary widely. Surprisingly, none show a straightforward relationship between local extinction and limited tolerances to high temperature. Instead, many studies implicate species interactions as an important proximate cause, especially decreases in food availability. We find very similar patterns in studies showing decreases in abundance associated with climate change, and in those studies showing impacts of climatic oscillations.

Evolution:

Besides being a good review of the state of the art, this is an excellent reference article:

I also provide tables with full or summarised data on (a) genital asymmetry across all animal phyla with internal fertilisation; (b) genera with dextral as well as sinistral species; (c) species with dextral as well as sinistral individuals; (d) genera with symmetric as well as asymmetric species; (e) species with symmetric as well as asymmetric individuals.

(Historical) Geology:

The break-off of India from Gondwana and its subsequent crash into Asia, forming the Himalaya Mountains, is one of the most spectacular events in Earth?s history ? the Himalayas changed climatic conditions (including setting the stage for human evolution!), and the sheer speed at which India jetted into Asia is remarkable. There?s even speculation that it may have played a role in the Cretaceous extinction, since its path went through the Reunion magmatic hotspot, where India might have picked up the lava that later went into the Deccan Traps. This reviews deals with how India evolved during this time.

A geochemical analysis of the most important Chinese Ediacaran localities (including Dengying and Doushantuo), with implications for palaeoenvironment. See Bristow et al. (2009) for more information.

Palaeontology:

Phosphatocopines are a group of 60+ Cambrian bivalved arthropods (probably crustaceans) with a unique, phosphatised carapace.

Not all impacts are globally-devastating events.

I didn?t know people still wrote Cenozoic like that.

The earliest flying fish fossil!

Zoology:

Cool party trivia.

I wrote about this cancer and its detrimental effect on the Tasmanian Devil in this post (the charity offer is long gone by now, although you should still buy that book anyway).