Christopher Hitchens in Collision with Religion [The Primate Diaries]
It's been an unusually busy week, so I apologize for the lack of original posts, but I just came upon Christopher Hitchens' latest piece in Slate reflecting on the many debates he's had with religious proponents in the last few years. His new film, Collision, looks fascinating and I look forward to reviewing it.
What struck me in Hitchens' article, and what I've found when discussing religion with theists as well, is how few of them hold literally to the doctrine that they espouse. It is one of the curious aspects of religion today that people will join movements insisting that religion be taught in science classes, but won't agree on which parts of that religion they even believe in.
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Danes Run Entire Urn Burials Through CT Scanner [Aardvarchaeology]
The jaw-drop moment of the conference came for me when osteologist Lise Harvig off-handedly showed us pictures of what she is doing. She's a PhD student with Niels Lynnerup at the Dept of Forensic Medicine at Copenhagen. Remember the crumbling Neolithic amber bead hoard that the Danes ran through a CT scanner instead of excavating and stabilising the thing? Now Lise is putting entire Bronze Age urn burials through that scanner. She knows where every piece of bone and bronze is in those urns before she even cuts open the plaster they've been encased in since being lifted out of the ground. She has perfect 3D digital models of urns that fall apart when you remove the plaster. And she has demonstrated that a lot of the bone fragmentation, that has commonly been assumed to be due to dedicated crushing and grinding by the mourners, is actually simply due to the brittleness of burnt bones whose organic component has leached away over the millennia. Big bones are sitting in the urns, each fragment in place, and fall apart when you try to lift them. As Lise put it, "The one who does the ritual crushing is me, when I empty the urns".
So, how can a PhD student in archaeology afford to use this sort of hi-tech equipment? Turns out, the technology is developing so fast that the hospitals frequently swap their CT scanners for newer models. The used one at the Dept of Forensic Medicine makes one slice every three millimeters. Not good enough anymore for brain surgery. But perfectly useful for archaeology.
Other issues covered in today's presentations were:
- Correspondence analysis of Gotland's stone ships.
- The landscape situation of sacrificial sites in the Lake Mälaren area (me).
- An Early Bronze Age magnate farm excavated recently near Halmstad.
- Human sacrifice and corpse rituals in Lithuania.
- The unusually late introduction of animal husbandry in Finland.
- Bone pins in the Baltic states.
- Copper in Fennoscandia before the Bronze Age.
- Bronze ring casting sites on Saaremaa and elsewhere in the Baltic states.
Colombian volcano update: Huila and the anniversary of the Armero lahar [Eruptions]
There has been news over the last few days of a number of volcanoes in Colombia, so I thought I'd try to gather it up here:
The steaming summit of Nevado del Huila in Colombia
- Nevado del Huila has been ramping up its ash emissions, potentially pointing towards new eruptions from the crater dome. The NASA Earth Observatory posted a new image of the grey ash plume from the volcano poking its way up through the clouds. This plume made it all the way to ~11 km / 36,000 feet, so it definitely isn't insignificant. This comes after an increase in seismicity (up to 1,000 earthquakes in the last week) at the volcano over the past few weeks, suggesting that new magma might be making its way up the conduit. Currently, INGEOMINAS has the alert status at Huila at Orange/II (eruption in days to weeks) according to the Volcano Observatory in Popayan. The current sulfur dioxide flux is up to ~7,400 tonnes/day and a number of explosions have also been registered on the seismometers. You can check out the webcam for the volcano here to see the latest (and the Volcanism Blog has some nice webcam captures of the recent activity.
- There is also a brief article on Hawaii 24/7 by the one of the geologists at HVO on what we're learned from the Nevado del Ruiz lahar in 1985 that killed ~25,000 people in Armero (and the nearby area). It is a nice summary of the events and consequences for those of you unfamiliar with the tragedy that occurred 24 years ago this November 13th.
Science Explains Why Boston’s Red Line Sucks So Badly [Mike the Mad Biologist]
One of the enduring mysteries of Boston's transit system is why is the Red Line always fouled up. I can understand why the Green Line is squirrelly: parts of the Green Line run above ground and intersect with traffic, the above ground stops take much longer at the stations (to prevent people sneaking on without paying, only the front door of each car opens), and, inbound, there are four different Green Lines that merge into one. In other words, the Green Line is a guaranteed clusterfuck.
But the Red Line has none of these problems. So why is it almost always screwed up, even when it doesn't break down? (equipment failure is a topic for a separate post--I've been following this and there are roughly two delays every day due to equipment failures).
Thank goodness WE HAZ TEH SCIENTISMZ!!
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Carl Sagan’s Baloney Detection Kit [The Primate Diaries]
Michael Shermer in a video produced by the Richard Dawkins Foundation
Big-headed tiger snakes support long-neglected theory of genetic assimilation [Not Exactly Rocket Science]
Tiger snakes are a group of extremely venomous serpents found all over the southern half of Australia, and on many of its islands. Some were cut off from the mainland by rising sea levels more than 9,000 years ago, while others were inadvertently introduced by travelling humans and have been around for less than 30 years.
When the snakes first arrive on an island, they find prey that are generally larger than they're used to on the mainland. That puts them under strong evolutionary pressure to have larger heads, in order to swallow larger meals. But by feeding snakes from different populations with prey of varying sizes, Fabien Aubret and Richard Shine have found that the more recent immigrants solve the need for larger heads in a very different way than the long-term residents.
Young populations do it by being flexible. If growing tiger snakes from newly colonised islands are fed on large prey, their heads rapidly enlarge to cope with the sizeable morsels. This flexibility is an example of "phenotypic plasticity" and it doesn't involve any genetic changes.
But Aubret and Shine found that older populations lack this flexibility - they have larger heads from birth and the size of the prey they eat doesn't affect the way they grow. These adaptations are fixed in their genomes. In the heads of tiger snakes, Aubret and Shine have found evidence for a 67-year-old concept in evolution called "genetic assimilation", which has very rarely been tested and is often neglected.
Its name might conjure up images of science-fiction and DNA-stealing aliens, but genetic assimilation simply describes a means of adaptation. It was proposed in 1942 by Conrad Waddington, who suggested that species initially cope with fresh environments by being flexible - through plasticity. All species have a certain amount of variation built in to their developmental program, which they can exploit according to the challenges they face. In this case, the tiger snakes can grow larger heads if they encounter bigger meals.
But as populations face constant evolutionary pressures, natural selection eventually favours genes that produce the same results, the ones that plasticity once achieved. This is the crux of Waddington's theory - in time, natural selection eliminates plasticity by fixing genes for the same traits. Such genes as said to be "canalised".
Back in the 1950s, Waddington demonstrated this using fruit flies. He exposed developing flies to ether vapour and found that some developed a second thorax (the middle segment between the head and abdomen). By anyone's standards, that's a radical change, but one that was triggered by an unusual environment. Over time, Waddington selectively bred the double-thorax individuals and exposed each new generation to ether. After 20 rounds of this, he found that some flies developed a second thorax naturally, without being exposed to ether. The double-thorax trait, which was initially induced by the environment, eventually became governed by the fly's own genes.
It was a neat idea, but finding other natural examples has been very tricky. Aubret and Shine thinks that genetic assimilation tends to happen over such short timescales (geologically speaking) that you can only really detect it under unusual circumstances. And the spread of tiger snakes across Australia certainly fits that bill.
Aubret and Shine's experiments show that snakes from newly colonised areas had the greatest degree of plasticity when it comes to head size while those from the longest-colonised islands had the least. These differences become abundantly clear when you compare snakes from three populations.
Tiger snakes have only been on Trefoil Island for 30-40 years and the jaws of their hatchlings are still small. However, they're also plastic - if they eat big meals, they'll grow bigger. On Carnac Island, tiger snakes have been around for 90 years and there, the hatchlings have moderately sized jaws and a relatively high degree of plasticity. On Williams Island, the tiger snakes have been cut off from the mainland for 9,100 years and their jaws are not only large from birth but their growth has very little plasticity.
The differences between the Trefoil and Carnac serpents are particularly interesting, because they suggest that the process of genetic assimilation can take place over a very short span of time, as others have predicted. It starts manifesting within just a few decades, even in animals like tiger snakes that only breed after their second or third birthday. This rapid pace could explain why it's very difficult to observe this process in the wild.
Reference: Current Biology 10.1016/j.cub.2009.09.061
Images: Tiger snake by Ian Fieggan
More on evolution:
- Museum butterfly collections chronicle evolutionary war against male-killers
- Decay of enamel-forming gene linked to evolutionary loss of enamel
- Scientists tickle apes to reveal evolutionary origins of human laughter
- From day to night - a lesson in eye evolution with the owl monkey
- How diversity creates itself - cascades of new species among flies and parasitic wasps
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Japan preparing up to $5 billion in Afghan aid: report (Reuters)
TOKYO, Oct. 31, 2009 (Reuters) -- Japan is preparing new aid for Afghanistan of up to billion to be used to help former Taliban fighters find jobs and build roads, a big increase from previous commitments, the Nikkei newspaper said on Saturday. ... > read full story
Typhoon cuts power, uproots trees in Philippines (Reuters)
MANILA, Oct. 31, 2009 (Reuters) -- The third typhoon to hit the Philippines in five weeks slammed into the main island of Luzon on Saturday, uprooting trees and toppling power lines, but there were no immediate reports of widespread damage. ... > read full story
Mexican farm leader killed with 14 others on ranch (Reuters)
MEXICO CITY, Oct. 31, 2009 (Reuters) -- Gunmen killed fifteen people on an isolated ranch in northern Mexico, including a prominent farmworker leader, in the latest grisly attack in an area overrun by drug gangs, local police said on Friday. ... > read full story
Feds to seize LA bank in 4th biggest failure: report (Reuters)
LOS ANGELES, Oct. 30, 2009 (Reuters) -- Regulators are expected to seize Los Angeles-based California National Bank on Friday in what would be the fourth-largest U.S. bank failure this year, the Los Angeles Times reported, citing unnamed sources. ... > read full story