Why Evolution is True is a blog written by Jerry Coyne, centered on evolution and biology but also dealing with diverse topics like politics, culture, and cats.
Clicking the image send visitors to Google’s search reults page for “End of the 13th Baktun”.
The 13th Baktun is the last cycle of the Mayan calendar, due to end today, December 21 2012. A Baktun is a period of almost 400 years.
The date has been misinterpreted as the heralding end of the world, but descendants of the Mayans have insisted the calendar merely resets and there will be no apocalypse. Instead, a 14th Baktun offers hope and change, they claim.
Sort of like theologians, aren’t they?
Neverthless [sic], across the globe people were last night converging to witness the apocalypse at sites including Mayan ruins, Stonehenge, Stalin’s bunker in Moscow, Byron Bay in Australia, and a sacred mountain in France.
In Central America believers flocked to ancient Mayan sites like Caracol in Belize, where they watched light passing through purposefully positioned structures, just as the inhabitants would have done over a millenium ago.
Paleontologists sometimes use terms that are rather different from the rest of the scientific community. One of my favourites is ‘enigmatic’. This term is often and appropriately applied to the soft-bodied multicellular organisms found in the Ediacaran strata (635-542 million years ago), which immediately predate the Cambrian rocks that saw the astonishing ‘explosion’ of multicellular animal life.
Indeed, so enigmatic are the fossils found in the Ediacara that many palaeontologists refer to the organisms that left these remains as ‘the Ediacaran biota’, maintaining a strictly agnostic position as to whether the organisms were animals, plants or something else entirely.
Here’s an example of how weird these things can be: Parvancorina. These fossils are 1-2 cm in length. They could be a hold-fast (the remnants of some organism that was attached to the sea-bed), although there are things about the fossils that suggest this is not the case. Other people have suggested they may be some primitive arthropod (the lack of any sign of legs suggests to me that this is a superficial identification).
In an article published online in Nature last week, geologist Gregory Retallack of the University of Oregon put forward what he accepts is an ‘unconventional’ hypothesis. Not only does he suggest that Parvancorina, which is often identified as an animal, was in fact a fungal fruiting body, above all he suggests that these fossils are not, as is universally accepted, from marine layers, but were in fact overwhelmingly terrestrial. This would mean that life first colonised the land at least 100 million years before the currently accepted dates (mid-Ordovician).
Using a close reading of the geological evidence, he applies this categorisation to most of the iconic Ediacaran fossils and reinterprets them as organisms that lived on dry soils. (Retallack has been arguing this for some time. Here’s a link to a 1994 paper of his arguing essentially the same thing, though with less geological detail. – the key thing in the new paper is his confident assertion that the rocks were terrestrial.)
So, for example, Retallack argues that Dickinsonia is ‘more likely to have been lichens or other microbial consortia’ rather than an early invertebrate. But he is arguing here simply on the basis of the geological identification of the rocks as being terrestrial – which he accepts is cotnroversial – not on the basis of the anatomy of the fossil.
Here is Dickinsonia. I appreciate that taphonomy – the way that things decay and become fossils – can have weird effects, but I find it hard to see this as anything other than an early invertebrate.
Unusually, the appearance of Retallack’s research article was accompanied by the publication of four ‘magazine’ articles, the first of which is an Editorial, justifying the publication of the article partly on the basis that previous whacky theories (eg Jane Gray’s advocacy of an Ordovician terrestrialisation date – around 460 million years ago) have become accepted. But as we know, most of the people who argue against a widely-accepted scientific view are not like Galileo, they are simply wrong.
That’s certainly the view of two of the three other pieces that accompany Retallack’s article. Shuhai Xiao dismisses Retallack’s terrestrial interpretation and puts forward counter-arguments for Retallack’s view. One of his most telling points is made by this picture. It shows Dickinsonia fossils on a bed of rock. And if those aren’t undersea ripples, I’ll eat my geologist’s hammer (I don’t have one).
J. GEHLING/SOUTH AUSTRALIAN MUSEUM
In an online article at Nature News, Brian Switek has hunted out quotes from other geologists:
“I and my colleagues are quite weary with being asked to review his material over the last ten years,” says James Gehling, a palaeontologist at the South Australian Museum in Adelaide.
Guy Narbonne, a palaeobiologist at Queen’s University in Kingston, Ontario, says that the new paper is little more than a summary of Retallack’s “long-standing views” on Ediacaran life.
He adds: “Most of us appreciated that Retallack’s lichen hypothesis was innovative thinking and tested his ideas critically, but it quickly became clear that there are simpler explanations for the features Retallack had validly noted, and most of us moved on to more promising explanations.”
Gehling is unconvinced by the new paper: “Retallack has presented not a single piece of evidence that would contradict the interpretation of the sedimentary layers involved as anything other than marine.”
He and Narbonne argue the red coloration of the rock and its weathering patterns, which Retallack presents as new evidence, could be just as easily accounted for by a marine origin.
Narbonne says that “multiple sedimentary and geochemical approaches by multiple independent laboratories worldwide have nearly universally converged on a marine origin for the Ediacara biota”.
Traces of animal behaviour in the wave-rippled Ediacaran sediments also contradict the terrestrial hypothesis, in Gehling’s view. Dickinsonia, an animal possibly related to today’s blob-like placozoans (the simplest multicellular organisms), left tracks after “spending time on one site, decaying the organic matter below, and then creeping across the mats to the next site,” he says, and the “mollusc-like” Kimberella created scratch marks on the sea floor as it grazed.
“If 60 years of published interpretations of the Ediacara biota have shown anything,” Gehling says, “it is that the Ediacara biota were a diverse array of organisms with remarkably consistent body plans found in distinct associations and most often preserved in place on fossil sea floors.”
Retallack remains unfazed. “I am expecting controversy,” he says, adding that he anticipates “the usual trajectory of grief, beginning with denial, then proceeding to mourning and acceptance” of his idea.
I’m no geologist, and as Paul Knauth, who remains open to Retallack’s suggestion rightly says in his commentary ‘We were not there when all this happened’. However, as a biologist with an interest in paleontology (I teach this stuff to second year students, and will include Retallack’s ideas in my lectures next year) I think that ‘mourning and acceptance’ might be the future for Retallack, not for the rest of us. As to what exactly the Ediacaran biota were, that remains one of the most fascinating enigmas in science.
Today’s Google doodle celebrates 200 years of “Kinder- und Hausmärchen”, otherwise known as Grimm’s Fairy Tales (see the Telegraph story here. If you go to the site and click on the right arrows, you’ll see 22 images that tell the story of Little Red Riding Hood, originally known as “Das Rotkappchen” (“The Little Red Hat”).
Have fun!
You can read about the Brothers Grimm and their famous collection of folk tales here.
The American Association for the Advancement of Science (AAAS), America’s premier science organization (and publisher of the prestigious journal Science) has for several years run an accommodationist program called the “Dialogue on Science, Ethics, and Religion” (DoSER). I’ve written about DoSER before (e.g., here, here and here), detailing its unholy crusade to wed science and faith. The program is, of course, funded by Templeton: a huge 5.3 million-dollar grant lasting eighteen years!
Have a look at the DoSER site (especially their upcoming Christmas lecture), and tell me that you don’t find it embarrassing: something that a scientific organization has no business doing. If you’re a member of the AAAS, or subscribe to Science, be aware of what your organization is up to. Science organizations shouldn’t be pushing an approved brand of theology, for that’s precisely what DoSER is doing. It’s endorsing, in effect, that rare brand of evangelical Christianity which nevertheless accepts evolution. It doesn’t, for instance, try to prescribe an accommodationist brand of Islam.
Anyway, thanks to the largesse of Templeton, you too can become a Professional Accommodationist, for the AAAS has three jobs up for grabs in the DoSER program. Here’s a screenshot of one:
Yes, apply now, but be aware that your job is to make nice to evangelical Christians. There “potential for renewal,” too, which means that Templeton may throw another pot of cash at DoSER when their grant expires in a year.
So here we have America’s premier science organization pushing a special theological point of view. It’s embarrassing, and I’m sure Britain’s Royal Society doesn’t have anything like this. That’s especially telling because the UK has an official state Church and the U.S. mandates separation of church and state (granted, the AAAS isn’t a government organization).
h/t: To the author of the website No Cross, No Crescent, who called my attention to the ad and has now written his own post on the matter with the straightforward title, “A word to Science: stop kissing the butt of evangelicals.”
The battle against creationism is never-ending, but I declare three victories this week. The first is symbolic but important, the others not so consequential but fun.
1. Creationism banned in New Orleans. From The Raw Story (thanks to several readers who alerted me to this), we learn that “the New Orleans schools board has banned the teaching of creationism in that parish’s schools (a “parish” in Louisiana is the equivalent of a “county” in other U.S. states; it’s not a religious term). They also repudiated any books that, like those in Texas, have been altered to reflect a revisionist, right-wing history of the U.S. The pdf of the resolution is here, and here are the relevant statements:
No history textbook shall be approved which has been adjusted in accordance with the State of Texas
revisionist guidelines nor shall any science textbook be approved which presents creationism or
intelligent design as science or scientific theories.
No teacher of any discipline of science shall teach any aspect of religious faith as science or in a
science class. No teacher of any discipline of science shall teach creationism or intelligent design in
classes designated as science classes.
As the Raw Story reports,
None of the six schools run by the board actually teach creationism, according to The Times-Picayune, but outgoing Orleans Parish School Board President Thomas Robichaux felt strongly about the measure (PDF) anyway, which passed in two parts. . .
Thus the victory is symbolic, but still important because the Louisiana governor and legislature are constantly pushing faith and creationism in the public schools, using both proposed legislation and voucher programs for religious schools (recently defeated). And New Orleans is the most important city (and parish) in Louisiana, and thus a bellwether.
2. The Discovery Institute caught with its pants down. According to Panda’s Thumb (“The Disco ‘Tute’s fake laboratory“), and a post at ars technica, the Discovery Institute has embarrassed itself by posting a video supposedly taken in the Biologic Institute, the part of the D.I. that engages in scientific “research” (LOL!), but the background of the video is actually faked.
In the video below, “senior research scientist” Ann Gauger decries population genetics because similarity of DNA sequences between species like chimps and humans doesn’t necessarily show common descent (they have no explanation, of course, for why noncoding sequences match the posited evolutionary tree perfectly).
But have a look at their “lab.” It isn’t their lab; it’s a stock photo taken—perhaps illegally—from a website full of copyrighted pictures. It’s been “green screened”!
3. More kerfuffle about young-earth creationist Paul Nelson. Finally, in a post at his site EvolutionBlog, “Coyne vs. Nelson,” Jason Rosenhouse revisits my pwning of young-earth creationist Paul Nelson when I checked up on his claims about the denigration of natural seleciton by prominent biologists.
Nelson argues that the commitment of science to methodological naturalism (MN) blinds scientists to what is put so plainly before them. It is a requirement of their profession that only naturalistic explanations are acceptable, you see. We are to believe, apparently, that this requirement is so blinding that they are unable to see things that are obvious to Nelson’s more clear-thinking audience.
This is the standard ID explanation for the popularity of evolution among scientists. It is, sadly, a ridiculous argument. As I explain in Chapter 20 of Among the Creationists, I have my problems with some of the rhetoric people on my side have used in defense of MN. But even if we accept Nelson’s characterization of it as a hard and fast rule, the fact remains that there is no requirement that scientists slavishly accept any old naturalistic explanation that comes along. It’s perfectly acceptable to say we don’t have a scientific explanation for the origin of species.
Moreover, being a scientist is not the entirety of anyone’s life. Scientists could agree that when practicing their profession they accept the constraints of certain conventions, and that invocations of supernatural intelligent designers are not part of their professional lives, while also believing that the evidence points strongly to an intelligent designer. But that is not what is happening. Scientists are not all mopey and dejected because their profession requires them to accept evolution when privately they think it’s a weak theory. Instead it is defended enthusiastically by virtually everyone in the relevant areas of science, while Nelson’s arguments are dismissed angrily not just as unscientific, but as totally worthless on the merits.
In Paul Nelson, who admits that the scientific evidence seems to point to an old earth but nevertheless rejects it, we have the pathetic stand of a man who holds fast to his fairy tales regardless of how strongly reality repudiates them. To be a young-earth creationist in this day and age is to be, frankly, an idiot.
UPDATE: Let me qualify that last statement. The “idiots” are not all young-earth creationists, for some have never been exposed to other viewpoints, or to the counterevidence for an old earth. Rather, the true idiots are those who know the evidence but refuse to accept it because they’re blinkered by faith. Nelson is one of those.
Let’s begin today with my favorite country song of all time: “Galveston“, written by Jim Webb and recorded by Glenn Campbell (b. 1936) in 1969. It’s a simple but beautiful ballad of a soldier (according to Webb, in the Spanish-American war) who, scared to death, dreams of his lover as he goes into battle.
Mel Tillis turned 80 this year, and also received the National Medal of Arts from President Obama for his contributions to country music. I doubt that many of you can name a single one of his songs, as he’s never crossed over into pop. Still, he did one song that I really love: “Send Me Down to Tucson“. It was written by Tillis and recorded in 1979, reaching #2 on the country singles chart.
If you’ve ever heard Tillis speak, you’ll know that he has a severe speech impediment: a bad case of stuttering. Curiously, although he can’t control it when he talks, when he sings it disappears completely. I think this is a common situation for stutterers, but I have no idea why; perhaps a reader can tell us. At any rate, this is a sad ballad about a man who loves a woman besides his wife.
There’s a so-so live version, but here’s the original recording:
Who remembers Gale Garnett? She’s the only country singer I know born in New Zealand (1932), but she later moved to Canada, swelling the sizeable ranks of that country’s folk and country singers.
She had but one big hit in her life, but it was a keeper: “We’ll Sing in the Sunshine,” written by Garnett and recorded in 1964. It won a Grammy for best folk single, but I’m calling it a country song. And it’s been covered by many artists, including Wayne Newton, Helen Reddy, The Fleetwoods, Sonny and Cher, and, for crying out loud, Dean Martin. The best alternative version, I think, is the duo by Skeeter Davis (whom we heard singing “End of the World” the other day) and Bobby Bare (listen to it here). Skeeter in particular does a great job.
The song was immensely popular in the Sixties, perhaps because it dealt with the exuberant sexuality of the “Free Love” era, but also the sadness underlying those transitory couplings. You can still hear the song all over the oldies stations.
This is the original version, performed live but lip-synched to the record:
Don’t expect deep thoughts today, for I have writing to do!
For some reason I’ve been posting a lot of arachnids lately. But this one is special: it weaves a web that contains a “fake spider” used as a decoy, so it’s a case of one of my favorite evolutionary phenomena—mimicry. Have a look:
A decoy spider hangs below its much smaller builder, suspected to be a new species in the genus Cyclosa. Photo: Phil Torres.
That big “spidery” thing in the middle isn’t a real spider, even though it has the requisite eight legs. It’s a dummy, woven (and with stuff added to it) by the much smaller real spider, which you can spot right above the dummy.
A piece by Nadia Drake at Wired Science explains (although leaves out some of the science):
A spider that builds elaborate, fake spiders and hangs them in its web has been discovered in the Peruvian Amazon.
Believed to be a new species in the genus Cyclosa, the arachnid crafts the larger spider from leaves, debris and dead insects. Though Cyclosa includes other sculpting arachnids, this is the first one observed to build a replica with multiple, spidery legs.
Scientists suspect the fake spiders serve as decoys, part of a defense mechanism meant to confuse or distract predators. “It seems like a really well evolved and very specialized behavior,” said Phil Torres, who described the find in a blog entry written for Rainforest Expeditions. Torres, a biologist and science educator, divides his time between Southern California and Peru, where he’s involved in research and education projects.
“Considering that spiders can already make really impressive geometric designs with their webs, it’s no surprise that they can take that leap to make an impressive design with debris and other things,” he said.
I teach about Cyclosa in my favorite lecture (on mimicry) for my introductory evolutionary biology class, but the species I show makes only a crude, spider-shaped figure in its web. I’ve never seen anything like this, and will be including it in my future lectures. Drake notes:
Though Cyclosa are known for building decoys, most of the described spiders’ constructions are clumpy, made out of multiple little balls built from egg sacs, debris or prey, rather than something resembling an actual spider. “Known Cyclosa don’t have that spider-with-leg looking thing, which is why we think it’s a new species,” Torres said.
As Drake does note, this dummy (an “extended phenotype” using Dawkins’s argot) gives the real spider protection from predators. Birds often eat spiders, and do so by striking the web. If there’s a big, juicy-looking dummy there, it’s much more likely to be struck by predators than the real spider, which can then escape being nommed. Ergo, the behavior is adaptive.
Now that’s a hypothesis, of course, and I’m not sure it’s been tested. One way to do that would be simply to monitor webs, seeing how often birds strike the dummy versus the real spider, and compare that to successful strikes of spiders that lack dummies. That would be hard work given the infrequency of predation events, but it’s the only way to buttress the story. But I suspect the story is real, simply because I can’t think of an alternative (a “Jerry-of-the-gaps” argument!).
Here’s another photo. It’s a remarkable likeness, attesting to the efficacy of natural selection, and I’m sure it would fool most human observers at first glance (and a glance is all that birds get). The fact that the real spider jiggles the dummy adds to the illusion that it’s real.
Photo by Phil Torres
A bit more on this amazing case of mimicry:
In September, Torres was leading visitors into a floodplain surrounding Peru’s Tambopata Research Center, located near the western edge of the Amazon. From a distance, they saw what resembled a smallish, dead spider in a web. It looked kind of flaky, like the fungus-covered corpse of an arthropod.
But then the flaky spider started moving.
A closer looked revealed the illusion. Above the 1-inch-long decoy sat a much smaller spider. Striped, and less than a quarter-inch long, the spider was shaking the web. It was unlike anything Torres had ever seen. “It blew my mind,” he said.
So Torres got in touch with arachnologist Linda Rayor of Cornell University who confirmed the find was unusual. “The odds are that this [species] is unidentified,” she said, “and even if it has been named, that this behavior hasn’t previously been reported.” Rayor notes that while more observations are necessary to confirm a new species, decoys with legs — and the web-shaking behavior — aren’t common in known Cyclosa. “That’s really kind of cool,” she said.
The Telegraph explains:
