Posts Tagged ‘arthropods’

What we talk about when we talk about arthropods

13 June 2013

you already saw these, and anyway the data are bit stale, and maybe the methodology is problematic but anyway I’ll put them here and forestall for the time being

png-2

the commentary about the fluidity (and pointlessness) of folk taxonomies and the just so of how the éscrevisse became a fish and how the fish became a dad

pngand the depauperate isopod fauna of the upper plains states (thanks to the Laurentide ice sheet and a lingering glacial hang-over? [I think I wish Vaux and Golder had asked about earthworms])

png-3

which reminds me I’ve never seen good explanation for the absence of lampyrids west of the Rockies [?] and why should lightning bug have such strong currency in the core of their North American range and firefly be such an outsiderism

png

and wow have we finally found the exception to the rule that your “bugs” aren’t bugs? News to me and  “water strider,” OK fine, but my favored childhood variant “water skeeter” doesn’t even poll ?!?!?1?!

As much as we use different words to talk about the same thing, it seems that we are just as likely to be using the same words to talk about different things see: “backstrider” “doodlebug” “potato bug” and on, and on, and

Screen shot 2013-06-12 at 11.29.37 PM

I mean. So you think the small grey terrestrial crustaceans that roll up in a ball are …

um centipedes. Dude did you even try counting their legs.

and don’t even get me started on nearly literal bugbear that is good old “daddy longlegs” except to note the sparse college town pockets that use “harvestmen” to call their opiliones. NERDS!

I think it was George Bernard Shaw that said, we are one country separated by a series of common misunderstandings about small animals with exoskeletons and jointed appendages and an imprecise and a wildly inconsistent vernacular applied to diagnose the same.

Or something like that.

Flippant

14 September 2011

Deep in some dream last night, I flip a rock and reveal an isopod the size of a silver dollar. Excited I snatch her up to show somebody, I cannot say who, but as I walk the crustacean ebbs to standard lilliputian proportions. Or maybe it’s my hands that are growing.

This all sounds pretty Jungian, or maybe worse, and I suppose soil is the great collective unconscious of terrestrial ecosystems (huh?)

But I guess I’m just a little haunted for not making more of International Rock-Flipping Day 2011.

I did get the chance to turn a few stones. As it happened, some of the same stones as when I first observed the holiday four years ago. Not surprisingly, more or less the same crowd turned up. Minus a weevil, plus a planarian.

Here I count representatives of no fewer than six independent invasions of land, not even counting the plants or fungi — nor the vertebrates which, apart from myself largely didn’t show. Hunkered beneath the twenty million-year-old fossilized shell of a bivalve, one clade that never made it out of the water in any respectable way. Sort of crazy.

Totally forgot the most important part:

Icon of evolution knocked from its perch, or, wait…how about “arthropod origins, waters around, muddied?”

10 August 2011

Since its original description six months ago, the fossil lobopod Diania has become one of the most celebrated fossils of all time, inspiring everything from elaborate back tattoos to a trendy sportswear line. This beloved “walking cactus” was championed by scientists as a key player in the origin of the most diverse and successful group of living animals. But startling new research suggests that this icon of evolution, this upstart URthropod, was in fact nothing more than an ordinary lobopod with bad skin.

In a series of brief communications published this week in Nature, two groups present revised analyses of the evolutionary relationships among 520 million year old fossil and its presumed relatives including euarthropods (e.g. insects, arachnids and crustaceans), anomalocarididsvelvet worms, water bears, and a variety of extinct stem-arthropods and lobopods, like the bizarre Hallucigenia. The phylogenetic analysis presented with the original description of Diania by Liu and colleagues found the creature to be closely related to a clade that included living arthropods and the outlaw Bavarian folk hero Schinderhannes, this result, coupled with the armored covered legs of Diania, was taken as an important clue to the origins of the stiff, jointed-appendages that are a hallmark of true arthropods.

However, the new reappraisals find Diania several nodes further removed from arthropod origins, mucking around in a polytomy that includes the tardigrades, onychophorans and extinct lobopodians. If these results are correct, it implies that the armored limbs of Diania are likely irrelevant to the origin of hardened jointed legs among arthropods. In a reply, Liu and company concede the tenuous placement of Diania in the family tree of arthropods and their relatives, but provide some additional support for their original interpretation and argue that further study is required to resolve the debate.

Surely, the question of whether Diania is a close relative of arthropods or not will continue to rock the paleontological community for years to come.

Refs:
Mounce, Ross CP and Matthew A Wills (2011) “Phylogenetic position of Diania challenged” Nature 476:E1 doi:10.1038/nature10266

Legg, David A et al. (2011) “Lobopodian phylogeny reanalysed” Nature 476:E1 doi:10.1038/nature10267

Liu, Jianni et al. (2011) “Reply” Nature 476:E1 doi:10.1038/nature10268

DOODZ! ALI∃NZ!!!1!

3 December 2010
Or maybe just a gravid female Mono Lake Brine Shrimp, Artemia monica.
heard if you go into the bathroom with a candle, turn the lights off, and whisper “reversed chirality” into the mirror seventy-three times you can actually *see* the shadow biosphere”

Well, I heard that arsenic makes you fat. And horny.

“Well, I heard that Tesla invented ununquadium-based life, you know, and hid it in a mountain in Colorado, and,”

I heard that Saturn’s moon Titan is made of liquid unicorns!”

Sorry.  The universe is a pretty crazy place, our own little stony clot of matter being no exception, and as things go, life is, really.

As I’m sure you have already heard, we are made of star stuff, and this connection is evident in how our own elemental makeup broadly mirrors that of the Earth and the Universe as a whole.  The six elements commonly regarded as the primary building blocks of life, hydrogen, oxygen, carbon, phosphorus, sulfur and nitrogen are the 1st, 3rd, 10th, 13th, 15th and 32nd most abundant elements in the Earth’s crust.  Other biologically important elements (e.g. iron, calcium, magnesium, sodium, potasium) largely round out the top 10 and the relative paucity of nitrogen in the crust is more than made up for by its superabundance in the atmosphere (thanks diazotrophs, we owe you one)

Stepping back a bit, CHNOPS and FeCaMgNaK all rank in the top 20 in elemental abundance in the universe.

To put things into perspective, arsenic, the subject of some breathless reportage today, is quite a bit rarer in the universe.  It ranks 41st in abundance in the universe, just behind tellurium (number 40) and just ahead of freaking yttrium (number 42).  The same goes for our own planet in particular where arsenic ranks at 48th in abundance by mass percentage.

(Incidentally, I got thes figures from WolframAlpha the first time that I’ve actually been able to put that seemingly powerful tool to any sort of meaningful use.)

Not to rain on anyone’s arsenic alien parade but if Earth’s boring old vanilla non-shadow biosphere (the overwhelming bulk of it anyway) is any indication, if life exists elsewhere in the universe it seems pretty likely that its elemental composition will more or less reflect the overall composition of the universe. Pinning hopes on a relatively scare substance, arsenic, when the alternative, phosphorous is rather abundant seems misguided. Just sayin’

 


These new experiments
show some bacteria already adapted to a fairly chemically extreme environment might, maybe, incorporate arsenic into their biomolecules when subjected to fairly elaborate artificial laboratory conditions.  But making the leap that this tells us something about what life outside (or hidden deep inside) our planet might be like, is equivalent to saying that because humans can survive and thrive with artificial hips that we should expect to find martian metazoans with composite titanium and plastic skeletons.

None of which is to say that this new discovery is anything short of totally rad. It also shows the value of doggedly pursuing what might seem like wacky ideas. That the prediction of parallel properties of arsenic and phosphorus might have biological significance is the stuff of science fiction, so it’s pretty easy to see why the press has gotten a little, uh, carried away by all of this. Also, dude, the periodic table came to Mendeleev in a dream!

Somewhat lost in all of the coverage about this remarkable Mono monad is the fact that Mono Lake sports an entire ecosystem that is very bizarre, if decidedly terrestrial. But you don’t have to take my word for it:

There are no fish in Mono Lake—no frogs, no snakes, no pollywogs—nothing, in fact, that goes to make life desirable. Millions of wild ducks and sea-gulls swim about the surface, but no living thing exists under the surface, except a white feathery sort of worm, one half an inch long, which looks like a bit of white thread frayed out at the sides. If you dip up a gallon of water, you will get about fifteen thousand of these. They give to the water a sort of grayish-white appearance. Then there is a fly, which looks something like our house fly. These settle on the beach to eat the worms that wash ashore—and any time, you can see there a belt of flies an inch deep and six feet wide, and this belt extends clear around the lake—a belt of flies one hundred miles long. If you throw a stone among them, they swarm up so thick that they look dense, like a cloud. You can hold them under water as long as you please—they do not mind it—they are only proud of it. When you let them go, they pop up to the surface as dry as a patent office report, and walk off as unconcernedly as if they had been educated especially with a view to affording instructive entertainment to man in that particular way. Providence leaves nothing to go by chance. All things have their uses and their part and proper place in Nature’s economy: the ducks eat the flies—the flies eat the worms—the Indians eat all three—the wild cats eat the Indians—the white folks eat the wild cats—and thus all things are lovely. – Mark Twain, Roughing It 1872.

Be sure to click through for more mildly racist humor (lighten up, dude, it’s satire!)  Somehow, Twain overlooked that other strange component of the Mono 80s hair-rockers.

The usual suspects have great, sober, and thought-provoking coverage of the new discovery.

Anyway though, if you really want to know about extraterrestrials, there’s only one person to ask:

Ours is not to look back. Ours is to continue the crack.

14 May 2010

Our traditionalist is now beginning to worry, but he will grant this one last point pour mieux sauter.  OK, the very first Cambrian fauna included a plethora of alternative possibilities, all equally sensible and none leading to us.  But, surely, once the modern fauna arose in the next phase of the Cambrian, called Atdabanian after another Russian locality, then the boundaries and channels were finally set.  The arrival of trilobites, those familiar symbols of the Cambrian, must mark the end of craziness and the inception of predictability.  Let the good times roll.

This book is quite long enough already, and you do not want a “second verse, same as the first.” I merely point out that the Burgess Shale represents the early and maximal extent of the Atdabanian radiation.  The story of the Burgess Shale is the tale of life itself, not a unique and peculiar episode of possibilities gone wild.SJ Gould Wonderful Life (1989)

Had it in my head, tindered by a typically turgid comment I left over at Jerry Coyne’s blog, to write something about the phantasmic Fezouata fauna. About contingency and determinism and prehistoriography.

The first god had, in his garden, one of these I'm sure. Ordovician marrellomorph from the cover of this week's Nature / Van Roy et al. 2010. A strong contender for my next paleo-ink.

About Wonderful Life and Crucible of Creation. About broken molds and Technicolor films. About checking the guy’s rock record and replaying life’s wobbly mistracked tape.

this is what the late eighties was like

[I biked over the library after Schluter’s talk and grabbed some books.  “That’s a small book,” the librarian remarked about the paperback version of WL, recut into hardback form, “but I’m sure it’s filled with big ideas”]

And about GOBE and rocks from space. About evolutionary anachronism and steampunk anomalocaridids and Schinderhannes. About Chengjiang and Emu Bay and Orsten.

[I Googled.]

About Caratacus and the Ordovices and predictable outcomes. About the Cincinnati arch and Creation Museum atop it. About how those that ignore history are doomed to not worry about it too much, along the way.

[I read.]

And yes about the other big and massively under-celebrated early Paleozoic news this week: Cambrian Bryozoans (!) and Gondwanan echinoderms.

[I typed.]

And ultimately about how, really, all of this maybe shows not so much about the fickle nature of history or the inevitability of intelligence or even about foolish it is to draw deep philosophical lessons from a crappy fossil record.  But that, well, the Earth was a really weird place 550, 450, 250, 50, 5 million years ago and that we have a lot more surprises in store and a lot more to learn.  But we will, in fits and starts, and what we do discover will change our picture of our place in the universe.  Or maybe it won’t.

[I hit delete.]

Because it’s Friday afternoon, and that all sounds pretty damn pretentious and sappy and inconclusive.  Why not throw together a link-heavy meta-post [I thought], then sit back and watch the links decay over the years until all that’s left is an ambiguous smear that’s difficult to make any sense of.

Then I remembered that it’s post a Fall song on your blog day.

Bat Macumba, Hey.

3 February 2010

First it was the oral sex.  Then with the boozing.

Now they’re joining gangs?

Someone has got to put a stop to this madness….

Yet another cool bat paper in PLoS today:

Dechmann DKN, Kranstauber B, Gibbs D, Wikelski M, 2010 Group Hunting—A Reason for Sociality in Molossid Bats?. PLoS ONE 5(2): e9012.doi:10.1371/journal.pone.0009012

I want to make a scansion joke here, but I’ve got nothing.  Here’s this instead:

1 Word Wednesday

20 January 2010

The word of the day is, “bogus” :

“If there is one color that is most decidedly not a classic Earth tone, one that is least associated with living things, it might just be neon blue.”  – Carol Kaesuk Yoon “Luminous 3-D Jungle Is a Biologist’s DreamNew York Times January 18, 2010

See also: Glaucus and Porpita, Blue Morpho, Sailfish, Blue-tailed Skink, William’s Electric Blue Gecko, a whole mess of Cichlids, Hyacinth Macaw, oh yeah and whatever the hell this is supposed to be.

Likewise, (watch to the end if you haven’t seen this before):