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An eclectic blog with mostly science related postings from the viewpoint of an evolutionary biologist.
Madhusudan Katti
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- August 23, 2010
- 05:22 AM
- 404 views
Overlooking the familiar in cataloging biodiversity
by Madhusudan Katti in a leafwarbler's gleanings
via myrmecos.net
Familiarity, they say, breeds contempt. Or, even if we aren't actually contemptuous of the familiar, we often simply ignore it. It is not surprising, then—although it should be—that Tapinoma sessile, the odorous house ant of North America, the very same little brown one that is pictured above, and that you may well have swept off your kitchen counter today, remains relatively poorly studied! It is so widespread and common across a variety of habitats in North America, it seems, that entomologists haven't really bothered to study it all that much since it was first described by Thomas Say, considered a father of American entomology.
So much so, that they even lost track of the original type specimen used to describe the species. How odd is that, for a widespread species not to have its identity securely moored to a type specimen enshrined in a museum somewhere? Almost like a nation's President not having a birth certificate!
When I accepted the offer of a faculty position in my current department here at CSU-Fresno six years ago, among other items on the startup list of equipment for my laboratory, I had (only half-jokingly) requested an espresso machine to boost my productivity. Hey, it had worked for my last postdoc advisor! But my then department chair, Dr. Fred Schreiber, only got a chuckle out of that one, and we moved on. A couple of years later, Fred called me up one afternoon to ask if I still wanted that espresso machine! A graduate student working in his lab had left one behind while moving on to the next stage of his career, and Fred had no use for it. That Starbucks Barista has since sat on a counter in my lab keeping me caffienated enough to get tenure and keep a research program afloat.
It so happened that, Chris Hamm, that graduate student who is now in the Ph.D. program at Michigan State University, had been studying the common odorous house ant, that same rootless species, for his masters thesis. While collecting specimens in California, he discovered a two-toned (or bicolored) variant that looked similar, yet rather different from the descriptions of T. sessile. So he carefully measured the two different morphs and compared their morphologies to find that they differ consistently (and statistically significantly) across a range of characteristics. So much so, that the bicolored morph must be recognized as a new species of ant!
A brand new species that was being trod underfoot daily in households across California, but had apparently never been looked at all that carefully by any entomologist in a region full of so many biologists! And we fret about losing biodiversity in remote corners of the world.
Chris has honored Fred by naming the new ant after him. Tapinoma schreiberi will forever mark the legacy of the man who has mentored so many in our department (including me as a greenhorn faculty member) over the past 3+ decades. How fitting that the paper was published the very year that Fred has taken early retirement, as of last week.
In the process of searching for the identity of this new ant, Chris also discovered the shaky foundation upon which rested the identity of T. sessile—and has done his bit to correct that injustice as well. He collected a new type specimen, from near the grave of its original discoverer, Thomas Say, to fill that huge hole in its taxonomic origin, even as he was giving it a new cousin! Alex Wild has more on that story at Myrmecos.
Now I find myself looking closely at ants around here, even as I sip my espresso and thank Chris for a good story, and for my morning/afternoon cuppa joe!
Reference:
Hamm, C. (2010). Multivariate Discrimination and Description of a New Species of Tapinoma from the Western United States Annals of the Entomological Society of America, 103 (1), 20-29 DOI: 10.1603/008.103.0104
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Hamm, C. (2010) Multivariate Discrimination and Description of a New Species of Tapinoma from the Western United States . Annals of the Entomological Society of America, 103(1), 20-29. DOI: 10.1603/008.103.0104
- December 2, 2010
- 07:02 PM
- 403 views
Arsenic and Old Lace
by Madhusudan Katti in a leafwarbler's gleanings
As you may very well have heard by now, NASA made a bit of a splash today in the mainstream media and especially the science (and sci-fi too, of course) blogosphere / twitterverse through its press conference about a fascinating biological discovery with potential astrobiological significance. An "alien" life-form that incorporates Arsenic (which normally kills our kind of life-form) instead of Phosphorus in the "backbone" of its very DNA. Actually its a bacterium from the mud at the bottom of Mono Lake, east of the Sierra Nevada in California, not some bug-eyed green monster from your sci-fi imagination, even though the lakescape itself has an otherworldly quality to it:
So, a bacterium that uses Arsenic is found in an old lake... well, the poor joke (and the title of this blog post) practically writes itself doesn't it? Maybe they should name this bacterium "old lace", as someone tweeted. Here's what the wee beastie looks like:
NASA's press conference was timed to coincide with the publication of a paper about this discovery, but the advance notice from NASA generated a fair amount of hype and breathless anticipation about "alien life" and so forth. The paper itself is now available at Science (perhaps behind a pay firewall, but maybe not), so you can read it and make up your own mind. The paper is very interesting indeed and the central discovery of this strange form of DNA in the bacterium leads to endlessly fascinating questions and speculations about the origin and evolution of life on this planet, and perhaps on others. The media hype surrounding the discovery, though... well, what can one say about media hype about such stories?
Rather than try to translate the paper for you poorly (me not being a microbiologist and all) or engage in more poorly-informed speculation, let me point you instead to several good blog posts that do a much better job than I ever could, and also offer a more balanced perspective to keep the hype in check but also share the excitement of such a fascinating discovery. To start with what's actually in the paper itself, Bhalomanush does a good job of describing the methodology underlying the discovery, while asking "Dude, where's my alien life?". Bad Astronomer Phil Plait, who had been urging caution to cool the hype building up in anticipation of NASA's announcement, offers a typically readable perspective on the real news. His fellow Discover magazine blogger Ed Yong offers perhaps the best commentary I have read on the whole discovery and pours some well-deserved cold water on some of the breathless hype. Over on ScienceBlogs, Greg Laden takes a more evolutionary perspective and places this study in the context of what it might—and might not—mean for the origin of life on our planet as well as Charlie Darwin's second theory about a common ancestor shared among all known lifeforms. Even if the paper is too much for you (some of it is for me because my PhD is in the wrong kind of biology for this stuff!), you'll do much better to read these blog posts rather than the more mainstream media accounts, I think.
Let's cool the hype a bit shall we, down to just the right level of simmering excitement at which the science can really thrive.
Reference:
Wolfe-Simon, F., Blum, J.S., Kulp, T.R., Gordon. G.W., Hoeft, S.E., Pett-Ridge, J., Stolz, J.F., Webb, S.M., Weber, P.K., Davies, P.C.W., Anbar, A.D., and, Oremland, R.S. (2010). A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus Science (early release on Dec 2, 2010).
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Wolfe-Simon, F., Blum, J.S., Kulp, T.R., Gordon. G.W., Hoeft, S.E., Pett-Ridge, J., Stolz, J.F., Webb, S.M., Weber, P.K., Davies, P.C.W., Anbar, A.D., and, Oremland, R.S. (2010) A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus. Science. info:/
- June 21, 2011
- 12:28 PM
- 335 views
The oceans rise, even as they decline... so long, fish!
by Madhusudan Katti in a leafwarbler's gleanings
Two interesting, alarming reports this week about what's happening (no small thanks to us) to the dominant habitat on this watery planet. First, that habitat is becoming even more dominant: a paper in PNAS meticulously reconstructs global sea-levels over the past two millenia to show that the oceans have been steadily rising, in concert with climatic changes, and that their rise has accelerated in recent years. This figure ought to worry you:
via realclimate.org
Meanwhile, though, that dominant habitat is also becoming emptier of inhabitants, as we continue to deplete marine wildlife in alarming ways.
via bbc.co.uk
So concludes an international panel of marine scientists convened by the International Programme on the State of the Ocean (IPSO). Even though conservation biologists have a reputation for being alarmists, this statement from one of the panelists, should worry you:
"The findings are shocking," said Alex Rogers, IPSO's scientific director and professor of conservation biology at Oxford University.
"As we considered the cumulative effect of what humankind does to the oceans, the implications became far worse than we had individually realised.
"We've sat in one forum and spoken to each other about what we're seeing, and we've ended up with a picture showing that almost right across the board we're seeing changes that are happening faster than we'd thought, or in ways that we didn't expect to see for hundreds of years."
via bbc.co.uk
There's more:
"The rate of change is vastly exceeding what we were expecting even a couple of years ago," said Ove Hoegh-Guldberg, a coral specialist from the University of Queensland in Australia.
"So if you look at almost everything, whether it's fisheries in temperate zones or coral reefs or Arctic sea ice, all of this is undergoing changes, but at a much faster rate than we had thought."
But more worrying than this, the team noted, are the ways in which different issues act synergistically to increase threats to marine life.
Those "different issues" include, of course, overfishing, pollution - especially from nasty plastics - ocean acidification, and warming. All adding up to the next mass extinction, one we are living through, unprecedented in being caused largely by a single species - us. So what are we to do?
IPSO's immediate recommendations include:
stopping exploitative fishing now, with special emphasis on the high seas where currently there is little effective regulation
mapping and then reducing the input of pollutants including plastics, agricultural fertilisers and human waste
making sharp reductions in greenhouse gas emissions.
Sounds simple enough, right? Clean up our act and take responsibility? So, we may know the way to back away from this rising, empty tide. Do we have the will?
Reference:
Kemp, A., Horton, B., Donnelly, J., Mann, M., Vermeer, M., & Rahmstorf, S. (2011). Climate related sea-level variations over the past two millennia Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1015619108
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Kemp, A., Horton, B., Donnelly, J., Mann, M., Vermeer, M., & Rahmstorf, S. (2011) Climate related sea-level variations over the past two millennia. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1015619108
- June 21, 2011
- 12:28 PM
- 290 views
The oceans rise, even as they decline... so long, fish!
by Madhusudan Katti in a leafwarbler's gleanings
Two interesting, alarming reports this week about what's happening (no small thanks to us) to the dominant habitat on this watery planet. First, that habitat is becoming even more dominant: a paper in PNAS meticulously reconstructs global sea-levels over the past two millenia to show that the oceans have been steadily rising, in concert with climatic changes, and that their rise has accelerated in recent years. This figure ought to worry you:
via realclimate.org
Meanwhile, though, that dominant habitat is also becoming emptier of inhabitants, as we continue to deplete marine wildlife in alarming ways.
via bbc.co.uk
So concludes an international panel of marine scientists convened by the International Programme on the State of the Ocean (IPSO). Even though conservation biologists have a reputation for being alarmists, this statement from one of the panelists, should worry you:
"The findings are shocking," said Alex Rogers, IPSO's scientific director and professor of conservation biology at Oxford University.
"As we considered the cumulative effect of what humankind does to the oceans, the implications became far worse than we had individually realised.
"We've sat in one forum and spoken to each other about what we're seeing, and we've ended up with a picture showing that almost right across the board we're seeing changes that are happening faster than we'd thought, or in ways that we didn't expect to see for hundreds of years."
via bbc.co.uk
There's more:
"The rate of change is vastly exceeding what we were expecting even a couple of years ago," said Ove Hoegh-Guldberg, a coral specialist from the University of Queensland in Australia.
"So if you look at almost everything, whether it's fisheries in temperate zones or coral reefs or Arctic sea ice, all of this is undergoing changes, but at a much faster rate than we had thought."
But more worrying than this, the team noted, are the ways in which different issues act synergistically to increase threats to marine life.
Those "different issues" include, of course, overfishing, pollution - especially from nasty plastics - ocean acidification, and warming. All adding up to the next mass extinction, one we are living through, unprecedented in being caused largely by a single species - us. So what are we to do?
IPSO's immediate recommendations include:
stopping exploitative fishing now, with special emphasis on the high seas where currently there is little effective regulation
mapping and then reducing the input of pollutants including plastics, agricultural fertilisers and human waste
making sharp reductions in greenhouse gas emissions.
Sounds simple enough, right? Clean up our act and take responsibility? So, we may know the way to back away from this rising, empty tide. Do we have the will?
Reference:
Kemp, A., Horton, B., Donnelly, J., Mann, M., Vermeer, M., & Rahmstorf, S. (2011). Climate related sea-level variations over the past two millennia Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.1015619108
Permalink
| Leave a comment »
... Read more »
Kemp, A., Horton, B., Donnelly, J., Mann, M., Vermeer, M., & Rahmstorf, S. (2011) Climate related sea-level variations over the past two millennia. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1015619108
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