About 24 cm from left to right.
It was growing on dead wood.
The previous fungus post was here.
Posted by AYDIN ÖRSTAN at 17:11
JOHAN MERTENS, LYNDA BELADJAL, ANGELICA ALCANTARA, LIESJE FOUGNIES, DOMINIQUE VAN DER STRAETEN and JAMES S. CLEGG (2008). Survival of dried eukaryotes (anhydrobiotes) after exposure to very high temperatures Biological Journal of the Linnean Society, 93, 15-22 pdf
Ever since Antonie van Leeuwenhoek demonstrated the appearance of animalcules* in cultures made with previously dry dust more than 300 years ago, biologists have been getting kicks out of pushing the limits of the survivability of dried animals and plant seeds. This is one of those studies the object of which seems to have been to demonstrate how high a temperature certain organisms can survive—regardless of whether or not the results had any biological significance.
Mertens et al. showed that the seeds or spores of various plants (Cardamine, Taraxacum, Adiantum, etc.), the cysts of the crustaceans Branchipus schaefferi (fairy shrimp) and Artemia franciscana (brine shrimp) as well as adult bdelloid rotifers and tardigrades survived exposures to temperatures as high as 130 °C for as long as 10 min.
The trick was to desiccate the seeds, spores and the animals first (for 3 days over silica gel) before heating them slowly at a rate of 4 °C per minute. However, the bdelloid Philodina did survive exposure to 120 °C even when it was heated rapidly (100 °C/min).
This is all very interesting, but what exactly do these results mean considering that these organisms are unlikely to experience such high temperatures in their habitats except perhaps during wild fires? The authors try hard to come up with a speculative scheme to explain how the ability to tolerate high temperatures could have arisen during the Devonian or earlier when the earth was supposedly a warmer place—but not that warm. But this doesn’t explain how adaptations to survive temperature extremes unlikely to be encountered in the organisms’ present or Devonian habitats arose to begin with.
Such extreme over-adaptations are likely to be the unintended byproducts of moderate over-adaptations to environmental stresses likely to be encountered occasionally. If desiccated rotifers and tardigrades or the seeds and spores of various plants are routinely exposed to temperatures around 40 °C, then those individuals that have evolved to incorporate a safety factor into their adaptation that makes them survive slightly higher temperatures, say 50 °C, will fare better in the long run when and if the habitat temperature happens to rise that high. It is likely that the mechanism that confers protection at 50 °C also protects at much higher temperatures that the animals will never experience as long as the cost of maintaining such a mechanism for occasional use is not too expensive.
*Leeuwenhoek’s animalcules were probably bdelloid rotifers, see Tunnacliffe, A. and J. Lapinski. 2003. Philosophical Transactions: Biological Sciences 358:1755-1771.
Posted by AYDIN ÖRSTAN at 13:08
Remember this beech tree that had fallen down sometime at the end of last year in the park near my house? I had been assuming since then that it was a dead tree. About 10 days ago I was standing on it (it forms a nice natural bridge over a small creek) when all of a sudden it dawned on me that its "dead" branches were covered with green leaves. Imagine my surprise.
Posted by AYDIN ÖRSTAN at 19:26
Posted by AYDIN ÖRSTAN at 18:19
Posted by AYDIN ÖRSTAN at 08:01
Posted by AYDIN ÖRSTAN at 17:57
This is the continuation of an earlier post about a poison ivy plant I photographed at the Georgetown University Hospital last week. I took this picture in Rock Creek Park not too far from the hospital on the same day.
Posted by AYDIN ÖRSTAN at 18:23
The reader Andrew Broome from New Zealand recently sent a link to a podcast of a Radio New Zealand interview with the owner of Silver Trail snail farm in Hawke's Bay New Zealand where you can get "hand-harvested gourmet snails".
The snail they are raising is the petit gris, or the little gray, which is a vernacular name for Helix aspersa (Cantareus aspersus, Cornu aspersum, etc.).
If you have 10 minutes to spare, listen to the podcast; it's entertaining. And I hope you'll understand their English better than I have. I think I got most of it, though.
Posted by AYDIN ÖRSTAN at 17:29
A Christian friend who also studies snails wrote in a recent e-mail:
I used to be religious, but nowadays my belief is getting weaker. For a biologist it is hard to be religious anyway...I have bought many cheap books from the David Brown Book Company over the years and am on their mailing list. An e-mail that came today announced several books that are on sale. This was one of them:
The Instruments of Torture, Revised and Updated - by Michael KerriganI am hoping it is the book that is revised and updated.
Posted by AYDIN ÖRSTAN at 18:05
Posted by AYDIN ÖRSTAN at 10:31
Lately I have been making frequent trips to Georgetown University Hospital in Washington, D.C. due to my wife's illness (details some other time). While walking along a wall at a busy section of the hospital yesterday, I noticed a lone plant growing out of a crack at the base of a brick wall.
Posted by AYDIN ÖRSTAN at 16:29
During yet another excursion to the used bookstore a couple of weeks ago, I found a near perfect copy of M. C. Escher, His Life and Complete Graphic Work. The price of $12 for an oversized 350-page book was one of those rare bargains.
Posted by AYDIN ÖRSTAN at 15:23
Posted by AYDIN ÖRSTAN at 18:10
The AMG Newsletter No. 15 is available here.
This issue contains articles on the mollusks found in excavations in the Middle East, the clausiliid Papillifera bidens (=Papillifera papillaris) in North Africa (seems like there is something about that snail in every issue of the Newsletter), an essay on the difficulties of distinguishing between mollusk shells modified by accidental or taphonomic processes and those intentionally modified by humans. There are also abstracts of recent relevant papers and books.
Posted by AYDIN ÖRSTAN at 13:17
Although I don’t work with freshwater snails and don’t know much about them, I happen to belong to the mailing list of a group of researchers interested in freshwater gastropods of North American (FWGNA) run by Rob Dillon of the College of Charleston. At irregular intervals, Rob e-mails to the group members his always informative and entertaining essays on various aspects of the taxonomy, ecology and biology of North American freshwater gastropods (archive). His essay of 25 February 2009 was about Charles Darwin’s interest in freshwater mollusks. Upon reading Rob’s piece, I remembered this post of mine from 2005 about Darwin’s experiments with land snails when he was trying to understand their dispersal mechanisms.
A few days later, I conceived the idea of combining Rob’s essay with my blog post in one article about Darwin’s work with mollusks in general. Rob liked the idea and I started working on it. I finished the first draft towards the end of March and sent it to Rob. He made some revisions and sent it back to me; I made a few more revisions and then sent the manuscript to Mollusc World, the magazine of the Conchological Society of Great Britain and Ireland.
Our joint effort, titled Charles Darwin the malacologist, recently got published in the July issue of Mollusc World. You may download a pdf version of the paper from here.
Darwin was truly a versatile biologist. The scope of his interests and the depths of his knowledge relative to what was known during his time are amazing.
Posted by AYDIN ÖRSTAN at 09:32
I had been meaning to attach my old camera to the front of my Greenspeed Anura to take pictures while riding. This afternoon I finally had a chance to do it. Because the camera's remote receiver is in the front, I had to turn the camera towards the back or at least sideways to be able to operate it with the remote from where I was sitting. Here is the camera attached to the front of the trike.
Posted by AYDIN ÖRSTAN at 18:17
Sometimes they just stay there, like this dead catbird I photographed the other day by the side of a road. It was probably a hit-and-run victim.
Posted by AYDIN ÖRSTAN at 19:11
Posted by AYDIN ÖRSTAN at 21:22
Posted by AYDIN ÖRSTAN at 17:05
Posted by AYDIN ÖRSTAN at 17:33
Time flies when you are procrastinating. I mentioned in this post back in December of last year that I was working on the material collected during a land snail survey we had done in Turkey early in the summer of 2004. I am still not finished, because after December I took a long break and worked on other stuff. I am now back at it and I intend to finish sorting all the specimens by the end of the year.
Imagine my pleasant surprise today when a bag of shells I picked randomly had the date of 4 July 2004. It seems like it was only, well, 5 years ago.
Posted by AYDIN ÖRSTAN at 20:38
This year is the 151st anniversary of the historic session of the the Linnean Society in London on 1 July 1858 when Charles Darwin’s and Alfred Russel Wallace’s independently developed ideas on evolution by natural selection were made public for the first time.
Darwin had been developing his ideas for 20 years, but before that day he had revealed them only to a few close friends and correspondents, including the American botanist Asa Gray. Wallace, on the other hand, had come up with his version of natural selection, very much similar to that of Darwin's, several months earlier while doing fieldwork in the Malay Archipelago and communicated it to Darwin in a now famous letter*.
The presentation at the Linnean Society was initiated with a letter of introduction by Darwin’s close friends Charles Lyell and Joseph D. Hooker, opening with the words:
My Dear Sir, -- The accompanying papers, which we have the honour of communicating to the Linnean Society, and which all relate to the same subject, viz. the Laws which affect the Production of Varieties, Races, and Species, contain the results of the investigations of two indefatigable naturalists, Mr. Charles Darwin and Mr. Alfred Wallace.This was followed by the reading of extracts from an unpublished essay Darwin had written in 1844, part of his 1857 letter explaining his ideas to Gray and the manuscript Wallace had sent to Darwin.
Posted by AYDIN ÖRSTAN at 13:53
A friend at work walked into my office today with a plastic water bottle containing a live snail. It was a gift* for me picked up by her husband yesterday in San Diego, California.
Posted by AYDIN ÖRSTAN at 18:14