Wednesday, December 31, 2008

2008 and all that

[muffled thumping] [wins laptop away from visiting small people who are disconcertingly better than me at “Diablo”]

Since everyone seems to be doing reviews of 2008, why should I be any different?! Except for the fact I don’t have the list of posts that everyone else has, but anyway . . .

OK Started on 26 October, and had a big boost by having some kindly pointers to the new blog by PZ, and Larry Moran.

I finally put a counter on Ediacaran on the 10th of December, and since then I’ve had 1645 unique visitors at an average of 75 (it was >80 before Christmas). I’ve got no idea if that’s good, bad, or indifferent, but I’m impressed.

A big hi to Vancouver, Washington State, Portland, Oregon, and Rimini, Italy. According to my statcounter, you three have the most visits, so thanks and keep coming back.

Also a big hi to Tebingtinggi, Indonesia, Lanzhou, China and Pune, India – some of the more exotic locations that people have recently logged on to Ediacaran from.

One thing the stats showed was that I got a big rise in hits at regular intervals. A little digging showed that the hits swelled after each posting of PalaeoPorn. This indicated one thing - you should all be ashamed of yourselves (but look out for a big PalaeoPorn tomorrow – nothing like starting the new year with a bang!)

As the assorted small visitors here are massing for a frontal assault for the laptop, I think a strategic withdrawal is in order. Thanks for coming by, and have a great and safe 2009.

Pedantic pedantry 1

OK, This is going to be an occasional series where I highlight where certain phrases or statements in the current science literature could have been . . . um . . . better thought through? Yes, better though through. Because as written, provides inadvertent fodder for the creationists/IDiots to quote mine.

Having some considerable experience with the various forms of creationism from Young Earth to ID, a common thread through most creationist claims is the misrepresentation of the scientific literature by taking short piece out of context or a single phrase or sentence to support their claims, when the piece as a whole clearly doesn’t. The creationist quote mine has been documented many times, and to be fair to creationists, is also employed by both AIDS deniers, and climate change deniers.

In order to starve the quote miners, authors need to be very careful in their phraseology. And so here is my contribution (every little helps, but this is also a case of those who can, write, those who can’t, contribute)

PP1 comes from:
Payne, J. L. et al. (2009) Two-phase increase in the maximum size of life over 3.5 billion years reflects biological innovation and environmental opportunity. Proceedings of the National Academy of Sciences, 106(1): 24-27.

The paper discusses an increase in body volume of 16 orders of magnitude for living organisms over the last 3.5 billion years, with two pronounced jumps of approx. 6 orders of magnitude 1.9 billion years ago and between 600-450 million years ago hence my interest). It is claimed that these two jumps are related to increases in the ambient oxygen concentration.

The statement under consideration here is the concluding sentence of the conclusion:

The size increases appear to have occurred when ambient oxygen concentrations reached sufficient concentrations for clades to realize pre-existing evolutionary potential, highlighting the long-term dependence of macroevolutionary patterns on both biological potential and environmental opportunity.

*polite cough* (See – I’m being polite)

The problem here is the phrase pre-existing evolutionary potential.

I’m going to assume here that the authors (all 13 of ‘em) didn’t mean to imply that evolution pump-primed organisms with abilities and then waited around until the conditions in which those abilities would be useful, occurred. In other words, the ability of organisms to grow big occurred in anticipation of the right environments that would allow such growth – which is what creationists will claim it says. See they will say, scientists say organisms were provided with pre-existing abilities prior to those abilities being useful. Only God a Designer could do that.

Undoubtedly what the authors intended was to say, was that, as increasing oxygen levels expanded the area of morphospace available for evolution to operate in, some clades that acquiring separate features to scavenge oxygen from the environment (gills), and a mechanism to transport that oxygen deep into the tissues (circulatory system with some oxygen-hugging components)- which was very useful even at lower oxygen concentrations - evolve larger forms as the ambient oxygen concentration increased. And not, that the features previously mentioned evolved to take advantage of future increases in oxygen levels.

Please remember – as far as creationist quote miners are concerned, it’s the words that count, not the intent.

Steven Jay Gould

I'm a big fan of Steve Gould. I don't agree with all of Gould's views, but I find I am in much more agreement with them than the 'British School', or adaptionists - which I find to be somewhat stagnant of late.

Anyhow, there are a couple of recent blog posts about Gould that I think deserve greater circulation, so they are here:

Sandwalk - An Adaptionist View of Steven Jay Gould

Laelaps - Stephen Jay Gould's view of life


Monday, December 29, 2008

Bestest documentaries ever

The best documentaries ever? Well, maybe not the best ever, but three television documentaries that, for me, represent important stages in the evolution of the documentary, and made an impact on me. Your mileage may vary.

1. The Ascent of Man (1973)
Number one . . . absolutely numero uno. For my mind, the best documentary ever made. Of any genre.

In Ascent, Jocob Bronowski lays out the development of human society and its understanding of science in an amazing series of programs.

In the late 1960’s the fledgling BBC2 television channel wanted to set itself apart from either BBC 1 or ITV. Its new Controller, a certain David Attenborough (yes THAT David Attenborough!) started marking out a place for BBC2 with the acclaimed documentary Civilisation with Kenneth Clarke, a 13 part series on the role of art in Western European culture (a terrific doco in its own right). This was to be followed by a doco on the history of science, but that doco – Ascent of Man – took so long to organise and film, that a third commissioned doco from BBC 2 was released second. That doco was another acclaimed piece – America with Alistair Cooke.

Not a bad day’s work for Mr Attenborough, getting three acclaimed documentaries commissioned.

All three are great examples of the ‘talking head’ documentary, where a single narrator carries the show and the vision is used to back the narrative. However, Ascent stands out for me as the best example of the type. It was the most expensive documentary made at the time, as crews covered 27 countries to get the required shots, and it included some of the first computer graphics ever seen on TV.

But Ascent stands out because, unlike Civilisation where you could poke a stick at whatever you were talking about (architecture, sculpture, paintings), Ascent dealt with concepts and theories. Both Bronowski and the BBC put a lot of thought (and money) into what visual devices to use to get the message across. However, it is Bronowski that dominates the screen, and his delivery, which initially can be grating, generally draws you in.

Ascent first aired in 1973, and, sadly, just over a year later Bronowski died of a heart attack

If you want a devastating rebuttal to the IDiots and their IDiotic film Expelled, watch this – the end of part 11 Knowledge and Certainty

A simply must see documentary series for anyone with even a passing interest in science.

2. Life on Earth (1979)

David Attenborough again! This time in front of the camera. This excellent series stands out for the exceptional photography, and represents a shift in documentary making away from the ‘talking head’ towards the moving image as the main ‘hook’ with the narration (and narrator) there to support and explain the imagery.

The first episode of Life on Earth ends in the Flinders Ranges of South Australia, with a shot of David Attenborough below some spectacular Ediacaran fossils (so I’m biased!)

The series is also famous for a sequence with Attenborough and some mountain gorillas.

3. The Civil War (1990)

What!? A Ken Burns documentary? Well, yes, the format has probably been overdone now, but The Civil War remains one of the earliest and best of what was another shift in documentary making, using archival footage, stills and multiple commentary from eye witness accounts, rather than the moving image. Or rather using film techniques to add movement to still images.

Wednesday, December 24, 2008

Why dinosaurs hate Christmas

Back by popular Demand

Did you know that most dinosaurs hate Christmas? It’s true, they do. And it’s not because they couldn’t get a handle on the present wrapping (or unwrapping for that matter) either. No, there is a very good reason why Dinosaurs hate Christmas.

However, before explaining why dinosaurs hate Christmas, lets deal with some startling new information. Everyone is familiar with the standard explanation for the extinction of the dinosaurs. I've included a common representation of the event.

However, startling 'evidence' has been presented which suggests another reason for what happened. The evidence is still officially hidden by the authorities, but one startling image has been smuggled out and is shown here for the first time.

It is claimed that it was an early experiment on propulsion systems that went wrong and had to be ejected. Shocking as this image is, there are some who claim that it is a forgery and just another shot by those at war with Christmas.

However, this is not the reason that dinosaurs hate Christmas. To understand that we need to know what dinosaurs are.

In his classic 1842 publication on dinosaurs, Richard Owen named and defined the Dinosauria as:
a group of exceedingly large, pachydermous reptiles from the Second Age . . . includes Megalosaurus, Iguanodon and Hylaeosaurus.

In 1997, Tom Holtz provided a different definition:
the last common ancester of Megalosaurus andIguanodon and all its descendants.
If it's changed since then, blame Holtz, but any changes will be mainly deckchair shuffling on the SS Chicxulub.

Anyhow, the thing about this definition is that, nestled between the Megalosaurs and the Iguanadons, are the Dromaeosaurs, and directly related to the Dromaeosaurs, and so one of the descendants mentioned above, is a little group called Aves!

So with the mass slaughter of birds dinosaurs every Christmas, wouldn't you hate Christmas?

If you insist in participating in this slaughter, at least make sure you cook your dinosaur correctly:

1. If your dinosaur is frozen, fully thaw it.

2. Don’t stuff the dinosaur. By the time the stuffing reaches a safe temperature, the meat is overcooked.

3. Cover the dinosaur breasts with ice while the rest of the dinosaur warms to room temperature. Don’t leave the dinosaur out for more than 3 hours. At this point, the breast will be about 40o Fahrenheit, while the rest of the meat will be at 60o Fahrenheit.

4. Put the dinosaur in the oven and cook according to your favorite recipe.

5. With a meat thermometer, check temperature. Take out of the oven when legs reach 82 Cedntigrade (180o Fahrenheit) and breast hits between 68 and 71 Centigrade (155o and 160o Fahrenheit).

Ho Ho Bleedin' Ho.

Tracking Santa

OK. it's getting close now, and pretty soon Santa will be starting his round the world trip.

NORAD have made their facilities available to allow you to track Santa's movements on his trip.

You will need to download a free application to allow Santa to be tracked via Google maps.

NORAD have been tracking Santa since 1955, when a Colorado Springs Sears Roebuck & Co. advertisement encouraging children to call Santa gave the phone number for the Continental Air Defense Command (CONAD - the predecessor to NORAD) Commander-in-Chief's operations hotline. CONAD provided updates to children who called and the practice has continued every since.

And we're off! Santa's on his way!

Tuesday, December 23, 2008

That's not a Christmas tree . . . THIS is a Christmas tree

This photo of the Christmas Tree Cluster was taken by the European Southern Observatory.

It is in NGC 2264, about 2600 light-years from Earth in the constellation Monoceros, the Unicorn, not far from of Orion.

Monday, December 22, 2008

PalaeoPorn 6

OK this one’s a bit of an indulgence. This is Megapharanaspis nedini a new genus and species of trilobite from the Lower Cambrian Emu Bay Shale in South Australia. It belongs to the Emuelloidea group of trilobite, a old group who’s members have lots of segments – considered an ancestral feature in trilobites.

It was collected by a team who worked on the site well after I had finished, so they named it after me!

Paterson, J. R. and Jago J. B. (2006) New trilobites from the Lower Cambrian Emu Bay Shale Lagerst├Ątte at Big Gully, Kangaroo Island, South Australia. Association of Australasian Palaeontologists Memoirs, Vol. 32, p.43-57.

1000th visit

This blog has just notched up it's 1000th visit (not visitor, but 1000th access to the blog) since I started the statcounter 12 days ago.

So take a bow Scunthorpe, North Lincolnshire, United Kingdom. If you logged on from there (or logged on from an IP address from there) at 6.30 am UK time, Hi (waves) you're the 1000th visit.

What I want for Christmas

Chris Rowan over at Highly Allochthonous has been doing some Christmas gift ideas for geologists.

This one is my favourate. It's science, it's history, it's art.


Sunday, December 21, 2008

The twelve geology days of Christmas

Ho Ho bleedin' Ho!

As Christmas is rapidly approaching, here (belatedly) is one version of the geology twelve days of Christmas.

Happy Monkey!

On the first day of Christmas my true love sent to me, a gas field in the North Sea.

On the second day of Christmas my true love sent to me, two turbidites and a gas field in the North Sea.

On the third day of Christmas my true love sent to me, three trilobites, two turbidites, and a gas field in the North Sea.

On the fourth day of Christmas my true love sent to me, four phenocrysts, three trilobites, two turbidites, and a gas field in the North Sea.

On the fifth day of Christmas my true love sent to me, five fossil fish, four phenocrysts, three trilobites, two turbidites, and a gas field in the North Sea.

On the six day of Christmas my true love sent to me, six slickensides, five fossil fish, four phenocrysts, three trilobites, two turbidites, and a gas field in the North Sea.

On the seventh day of Christmas my true love sent to me, seven seismic waves, six slickensides, five fossil fish, four phenocrysts, three trilobites, two turbidites, and a gas field in the North Sea.

On the eighth day of Christmas my true love sent to me, eight echinoids, seven seismic waves, six slickensides, five fossil fish, four phenocrysts, three trilobites, two turbidites, and a gas field in the North Sea.

On the ninth day of Christmas my true love sent to me, nine nunnatacks, eight echinoids, seven seismic waves, six slickensides, five fossil fish, four phenocrysts, three trilobites, two turbidites, and a gas field in the North Sea.

On the tenth day of Christmas my true love sent to me, ten Turitellas, nine nunnatacks, eight echinoids, seven seismic waves, six slickensides, five fossil fish, four phenocrysts, three trilobites, two turbidites, and a gas field in the North Sea.

On the eleventh day of Christmas my true love sent to me, eleven laccoliths, ten turritellas, nine nunnatacks, eight echinoids, seven seismic waves, six slickensides, five fossil fish, four phenocrysts, three trilobites, two turbidites, and a gas field in the North Sea.

On the Twelfth day of Christmas my true love sent to me, twelve welded tuffs, eleven laccoliths, ten turritellas, nine nunnatacks, eight echinoids, seven seismic waves, six slickensides five fossil fish, four phenocrysts, three trilobites, two turbidites, . . . and a gas field in the North Sea.

Saturday, December 20, 2008

"Get a life" meme

Oh ho! Another meme and this doesn't look good. There are 219 movies on the list. If you've seen more than 85 you have no life. I have no life! (101)

(x) Rocky Horror Picture Show
( ) Grease
(x) Pirates of the Caribbean
(x) Pirates of the Caribbean 2: Dead Man's Chest
( ) Boondock Saints
( ) Fight Club
( ) Starsky and Hutch
(x) Neverending Story
(x) Blazing Saddles
(x) Universal Soldier
(x) Lemony Snicket: A Series Of Unfortunate Events
( ) Along Came Polly
(x) Joe Dirt
(x) KING KONG – all versions
( ) A Cinderella Story
( ) The Terminal
( ) The Lizzie McGuire Movie
( ) Passport to Paris
( ) Dumb & Dumber
( ) Dumber & Dumberer
( ) Final Destination
( ) Final Destination 2
( ) Final Destination 3
(x) Halloween
(x) The Ring – Japanese version
(x) The Ring 2 – Japanese version
( ) Surviving -MAS
(x) Flubber Orignial version only
( ) Harold & Kumar Go To White Castle
( ) Practical Magic
(x) Chicago
(x) Ghost Ship
( ) From Hell
(x) Hellboy
( ) Secret Window
( ) I Am Sam
(x) The Whole Nine Yards
(x) The Whole Ten Yards
(x) The Day After Tomorrow
( ) Child's Play
( ) Seed of Chucky
( ) Bride of Chucky
( ) Ten Things I Hate About You
( ) Just Married
( ) Gothika
(x) Nightmare on Elm Street
( ) Si teen Candles
(x) Remember the Titans
(x) Coach Carter
( ) The Grudge
( ) The Grudge 2
(x) The Mask
( ) Son Of The Mask
(x) Bad Boys
(x) Bad Boys 2
( ) Joy Ride
( ) Lucky Number Sleven
( ) Ocean's Eleven
( ) Ocean's Twelve
(x) Bourne Identity
(x) Bourne Supremacy
( ) Lone Star
() Bedazzled both versions
(x) Predator I
(x) Predator II
( ) The Fog
(x) Ice Age
(x) Ice Age 2: The Meltdown
( ) Curious George
(x) Independence Day
( ) Cujo
( ) A Bron Tale
( ) Darkness Falls
( ) Christine
(x) ET
( ) Children of the Corn
( ) My Bosses Daughter
( ) Maid in Manhattan
(x) War of the Worlds
(x) Rush Hour
(x) Rush Hour 2
( ) Best Bet
( ) How to Lose a Guy in 10 Days
( ) She's All That
( ) Calendar Girls
( ) Sideways
(x) Mars Attacks 37
(x) Event Horizon
( ) Ever After
(x) Wizard of Oz
( ) Forrest Gump
(x) Big Trouble in Little China
(x) The Terminator
(x) The Terminator 2
(x) The Terminator 3
(x) x-Men
(x) x2
(x) x-3
(x) Spider-Man
(x) Spider-Man 2
( ) Sky High
( ) Jeepers Creepers
( ) Jeepers Creepers 2
( ) Catch Me If You Can
(x) The Little Mermaid
( ) Freaky Friday
( ) Reign of Fire
( ) The Skulls
( ) Cruel Intentions
( ) Cruel Intentions 2
( ) The Hot Chick
(x) Shrek
(x) Shrek 2
( ) Swimfan
(x) Miracle on 34th street
( ) Old School
( ) The Notebook
( ) K-Pa
( ) Kippendorf's Tribe
( ) A Walk to Remember
( ) Ice Castles
( ) Boogeyman
( ) The 40-year-old-virgin
(x) Lord of the Rings Fellowship of the Ring
(x) Lord of the Rings The Two Towers
(x) Lord of the Rings Return Of the King
(x) Indiana Jones and the Raiders of the Lost Ark
(x) Indiana Jones and the Temple of Doom
(x) Indiana Jones and the Last Crusade
( ) Baseketball
( ) Hostel
( ) Waiting for Guffman
( ) House of 1000 Corpses
( ) Devils Rejects
() Elf
(x) Highlander
(x) Mothman Prophecies
( ) American History
( ) Three
( ) The Jacket
(x) Kung Fu Hustle
(x) Shaolin Soccer
(x) Night Watch
(x) Monsters Inc.
(x) Titanic
(x) Monty Python and the Holy Grail
(x) Shaun Of the Dead
( ) Willard
( ) High Tension
( ) Club Dread
( ) Hulk
( ) Dawn Of the Dead
(x) Hook
(x) Chronicle Of Narnia The Lion the Witch and the Wardrobe
(x) 28 days later
(x) Orgazmo
( ) Phantasm
(x) Waterworld
(x) Kill Bill vol 1
(x) Kill Bill vol 2
( ) Mortal Kombat
( ) Wolf Creek
( ) Kingdom of Heaven
( ) the Hills Have Eyes
(x) I Spit on Your Grave aka the Day of the Woman
( ) The Last House on the Left
(x) Re-Animator
( ) Army of Darkness
(x) Star Wars Ep. I The Phantom Menace
(x) Star Wars Ep. II Attack of the Clones
(x) Star Wars Ep. III Revenge of the Sith
(x) Star Wars Ep. IV A New Hope
(x) Star Wars Ep. V The Empire Strikes Back
(x) Star Wars Ep. VI Return of the Jedi
( ) Ewoks Caravan Of Courage
( ) Ewoks The Battle For Endor
(x) The Matrix
(x) The Matrix Reloaded
(x) The Matrix Revolutions
( ) Animatrix
( ) Evil Dead
( ) Evil Dead 2
(x) Team America: World Police
( ) Red Dragon
(x) Silence of the Lambs
( ) Hannibal
( ) Battle Royale
( ) Battle Royale 2
(x) Brazil
(x) Contact
( ) Cube
(x) Dr. Strangelove
( ) Enlightenment Guaranteed
( ) Four Rooms
(x) Memento
( ) Pi
( ) Requiem for a Dream
(x) Pulp Fiction
(x) Reservoir Dogs
(x) Run Lola Run
( ) Russian Ark
(x) Serenity
(x) Sin City
() Snatch
( ) Spider
(x) The Sixth Sense
( ) The Village
( ) Waking Life
( ) Zatoichi
( ) Ikiru
(x) The Seven Samurai
( ) Brick
(x) Akira


I appear to have lost the ability to comment on my own posts. It's not that I have been ignoring people's comments, but whenever I try to put in a comment, the page refreshes and wipes the comment. If anyone has experience with Blogger and could help, please email me at cnedinatyahoodotcom. Thanks.

Thursday, December 18, 2008

New Australian geological map

Geoscience Australia have released new digital surface geology map of the whole of Australia. The map is a 1:1 million scale database and provides, for the first time, a seamless representation of Australia's geology over the whole country.

Previously, Australia had been mapped in sections by State and Territory Government agencies. This has resulted in geological information that did not match up across juristictional boundaries, or even between areas within juristictions. This is because of different data acquisition methods used, and timing - where one block would be surveyed, and an adjacent block surveyed years later when the methodology or standards had changed. This resulted in a patchwork covereage that was not consistant.

The new map is now seamless across the country, and this will help resource and environmental managers to better understand and interpret regional geology.

The map is free to download (after registration).

Tuesday, December 16, 2008

PalaeoPorn 5

This is Telson Guy - Lower Cambrian, Emu Bay Shale, South Australia (click on image for larger view). No official name yet as he hasn't been formally described. This is the only specimen that I collected, and his head and appendages are poorly preserved. But check out that telson (tail)! A good gut trace is also present as are the trunk segments.

The head and appendages are key to identifying which group Telson Guy belongs to. A recent team that worked on the site has collected many more specimens, but none in 3-D as this one is. However, they are working Telson Guy up and hopefully will provide a taxonomic home for him.

Monday, December 15, 2008

Rudd sells out Australia

Today the Prime Minister, Kevin Rudd, proved to full of hot air on climate change by setting a mandatory reduction in CO2 emissions target of a worthless 5% cut by 2020.

This abject failure of leadership is a stab in the back to all those who believed his (now obviously empty) rhetoric about needing leadership in tackling climate change.

They try and spin it by saying that it’s a large cut on a per capita basis. Well, yes, it would be, as Australia is ONE OF THE WORLDS BIGGEST CARBON POLLUTERS on a per capita basis – or more accurately Australian companies are amongst the worlds biggest polluters, which, given our small population makes us a large polluter on a per capita basis. This argument is like saying, "right, you pollute 50 tons and we pollute 500 tons. If you reduce your pollution by 50% or 25 tons, we'll reduce ours by 25 tons as well"!

So as we are amongst the biggest transgressors, we should take the biggest hit, shouldn’t we?

It’s the right thing to do.
It’s the fair thing to do.
It’s the moral thing to do.

But not in Rudd’s world, where the big polluters, who have been literally gouging massive profits for years, will be rewarded with low targets and billion dollar payouts as a reward for doing ABSOLUTELY NOTHING to prepare for carbon emission limits which they have known for years were coming. Not only that, but he has reduced the threshold for polluters to qualify for free permits to pollute, making the permit system even less effective at initiating change in the practices of our worst polluters.

The leader of the opposition, Malcolm Turnbull is probably slack-jawed in disbelief. That a Prime Minister should so comprehensively turn his back on those who voted for him and his platform of decisive action on climate change, to run into the arms of the only group in Australia that will not vote for him – big business. All Turnbull has to do now is sit tight and wait for the next election. After today, the odds of a single term government (a rarity in Australian politics) is suddenly on the cards.

More denialism from The Australian

The Australian newspaper is Australian media's version of Fox News. Still in denial about it's beloved conservative government losing the last election, the paper continues it's denial of global warming. Tim Lambert over at Deltoid has this story, and more on The Australian's denialist past.

Saturday, December 13, 2008

New Energy Secretary is a Steve

President-elect Obama has announce his Energy Secretary will be physicist Steven Chu. Professor Chu is, apart from Professor of Physics at Stanford, and a Nobel laureate, a member of Project Steve. This is a list of scientists names Steve (or Stephanie, or Stephan, etc.) who accept that:

Evolution is a vital, well-supported, unifying principle of the biological sciences, and the scientific evidence is overwhelmingly in favor of the idea that all living things share a common ancestry. Although there are legitimate debates about the patterns and processes of evolution, there is no serious scientific doubt that evolution occurred or that natural selection is a major mechanism in its occurrence. It is scientifically inappropriate and pedagogically irresponsible for creationist pseudoscience, including but not limited to "intelligent design," to be introduced into the science curricula of our nation's public schools.

The Project is run by the NSCE as a parody of the creationist tactic of compiling lists of "scientists" (most of whom have no connection to biology or evolution) that 'dissent from evolution'. In response the NSCE created Project Steve in honour of Steven J. Gould.

Professor Steven Chu should not be confused with Professor Steve Steve, who is far too busy a panda to be Energy Secretary.

Currently Project Steve is approaching 1000 'Steve's'.

Are you a Steve (or Stephanie, or Stephan, etc.)?
Are you a scientist?
Do you agree with the statement above?
Then go to Project Steve and sign up.

And while you are at it, sign up to NSCE. They do great work.

Thursday, December 11, 2008

PalaeoPorn 4

This is Myoscolex ateles from the Emu Bay Shale on Kangaroo Island South Australia. It's a view of the back end and tail, with appendages. I’ll be writing more about Myoscolex later because the gray material you can see is phosphatised muscle tissue – one of the earliest examples of preserved muscle tissue known.

Also I’ll be writing on it’s place in the animal kingdom, as it turns out to be an opabinid, one of the Burgess Shale “weird wonders” – or should I say that Opabinia is a myoscolexid, as Myoscolex is older than Opabinia!

As I said, the central light area is the phosphatised muscle tissue, but check out the fancy paddles! (Click on the image for a larger view)

Who’s got cute paddles then?
Yes you have.
Yes you have got cute paddles then!

Sunday, December 7, 2008

CSI Cambrian

[bum bum - bum - bum bum. Whooooo are you? - Who? Who? - Who? Who?]

Grissom: Well? What do we have?
Catherine: The deceased is a 0 foot 1 inch arthropod of uncertain gender
G: Hmm. Time of Death?
C: That’s proving a little difficult.
G: OK. Do we know how long the body has been there?
C: Best estimate is five hundred and nineteen million years.
G: [raises eyebrow]So not much left then?
C: Actually quite a lot. The lab guys say it’s in a lager statten.
G: Ah, Lagerst├Ątten. An old German mining term meaning “mother lode”. Used by palaeontologists to mean a deposit with exceptional preservation. So we’re in luck.
C: Yeah . . . right .

G: Do we have a cause of death?
C: Oh I think so. Death would appear the result of a large wound in the right side. A significant piece of the right side has been removed, and is missing.
No sign of a struggle at the site either, so it would appear that the attack took place elsewhere and the victim ended up here.
G: Got a name?
C: Naraoia? Possibly. Difficult to say at this stage.

G: What was the victim wearing?
C: The typical Naraoid two piece, a short anterior shield and a longer posterior shield. Although the posterior shield is a bit more stylish than normal, as it sharply tapers towards the back.

G: Any suspects?
C: Well, we’ve liked Anomalocaris for this type of attack for a while now, but we’ve never been able to make a solid case.
G: Why?
C: Well, despite the fact that Anomalocaris is pretty much the largest organism around, and it has jaws that could have made the bite marks we see in a number of victims, we know that the jaws probably didn’t come together very strongly. They didn’t . . . um . . . occlude. They didn’t occlude. Also the jaws themselves were not strongly mineralised.
G: [Begins to speak] Scl . .
C: [interrupting, rolling her eyes] Sclerotised, they were poorly sclerotised. And so couldn’t bite into strongly mineralised or sclerotised attire.

G: OK. Lets review the evidence.
C: Well we have a naraoid with a large wound on the right side.
G: Anything else?
C:Well, there’s some minor damage of the opposite side to the large wound, but we can’t tell if that was caused at the same time as the major attack or if it is unrelated. Anomalocaris is a suspect, but doesn’t appear to have been able to inflict the damage we see.

G: Whatever caused the wound also cut through the cuticle. What does that tell us?
C: Well, first we need to know about the properties of the cuticle. Arthropod cuticle has a bilayered construction, consisting primarily of a thin, usually mineralised, outer exocuticle, underlain by a thicker, unmineralised, endocuticle. Each of these brings differing mechanical properties, with the hardened exocuticle strong (and thus resistive to cracking) under compression (or being poked), but weak (and vulnerable to cracking) under tensional forces (or being stretched). By comparison, the softer, more pliant endocuticle is the opposite, weak under compression, but strong under tension. These properties combine to provide a greater level of protection against mechanical attack than either layer could alone.
By varying the thickness and mineralization of the two layers, arthropods can produce a wide range of exoskeleton types, from highly plastic to highly rigid.

G: I’m impressed
C: Yeah, well, you have so many arthropods crawling around your office that I though I should read up on them.

G: And what does that mean for the properties of the cuticle under pressure?
C: Well, Highly plastic cuticle can deform almost to breaking point and rebound back to its original shape when the pressure is released, kind of like pushing your fingers into a balloon and then letting go.
G: Elastic deformation.
C: Right. While highly rigid cuticle will show almost no deformation until the moment it breaks, kind of like pushing down on a dinner plate.
G: Remind me never to invite you around for dinner.
C: Cute. But most cuticle is a compromise between highly elastic and highly rigid.
G: So?
C: That means under low pressure, the cuticle shows plastic deformation, which will rebound if the pressure is released. But, at a certain level of pressure, the cuticle reaction changes.
G: The yield point.
C: Right. If the pressure exceeds that level, any deformation is permanent, like pushing your fingers into plasticine.
G: And if the pressure continues to increase?
C: Eventually the cuticle will fail

G: [Grissom’s phone rings. He puts it on speaker.] Warrick. Right on time. What did you find?
W: Grissom. As you asked, I looked at all the cases that had with a similar MO to the one you have there.
G: And?
W: You were right. In a significant number of instances, the victims had damage on the opposite side to the major injury.
I’m sending through a couple of photos. The first is from the same location but the victim was a Redlichia. The second is from Canada and shows a similar MO, but in this case the victim was Ogygopsis..
I’ve also got an example from the Ordovician, where the attacker was identified as a nautiloid.
G: As yes, the first example of our squid overlords exercising their might.
W, C: What?
G: Oh nothing, just a blog I read. Thank you Warrick. [Hangs up]
C: Nautiloid? There are no nautiloids at this location. How does that help us.
G; It’s all evidence. And we know the MO of nautiloids, they wrap their tentacles around the body of the pray and force it into the mouth, where the strong beak bites down.
C: But we have already established that that MO wouldn’t work with Anomalocaris because of the poorly sclerotised jaws.
G: Correct. Now with that, and the nautiloid MO in mind, lets re-examine the victim.
C: OK. Well the pressure exerted on the right side was clearly enough to break the cuticle.
G: Agreed. Anything else?
C: Umm . . . wait a minute, the damage to the left side! It’s permanently deformed
G: So?
C: Since it occurs in a number of cases it probably occurred at the same time as the major damage. That means it’s has significant pressure applied to it, enough to exceed the yield point. Maybe the attacker had two goes at the victim?
G: Possible, but I don’t think so. The margin is pinched in. it doesn’t look like a bite mark.
C: Well if the damage was done by an appendage, where is the second site of damage? Anomalocaris has two appendages.
G: Take a close look at the Pposterior shield. See along the margin?
C: It’s thicker! The cuticle folds back on itself. It would have been much stronger than the anterior shield margin.
G: Correct. Also the posterior shield tapers quite markedly, so the best purchase would have been on the anterior shield.

G: OK what else do we know about Anomalocaris?
C: It has a strong muscular head with powerful frontal appendages. But that’s what I don’t understand!
G: What?
C: The whole powerful appendages thing. Why have them? If all you are doing is holding the victim to your mouth, you really don’t need such powerful appendages.
G: That’s a good question. Unless . .
C: Unless . . . unless . . . the head and appendages are doing something else . . . something powerful . . .
G: So it’s not just guiding the victim to the mouth, the appendages are applying real pressure to the other side. Why?
C: It can’t be that the attacker was applying considerable force just to position the victim in the mouth, because the mouth couldn’t bite down. The force had to be doing something else.
G: Go on.
C: Well, the powerful appendages and head muscles must have been doing something in tandem with the weak jaws, something that was powerful enough the break the cuticle.

G: What do we know about the cuticle that can help us here?
C: Well, we know that the two-layered construction is best able to withstand the stresses associated with the downward force that normal biting would produce.
Wait a minute. What if it were possible to reverse this?
G: What do you mean?
C: Well, the cuticle is set up to withstand a compressive force on the upper layer, which translates to an extensive force on the lower layer as it stretches around the point of impact.
What if this were reversed, and the extensive force were applied to the upper layer?
G: Interesting idea, but how would you do that?
C: We know that the appendages were doing something that provided enough force to damage the side opposite the major wound. Maybe it was flexing the victim back and forth, using the jaws as a pivot point.
G: Like you would do to break a credit card?
C: Exactly. You can’t break a credit card with your hands, but you can force it to crack by flexing it back and forth.
G: I think you may have something here. So what is your description of the events leading to the crime?
C: The victim is attacked from the right hand side by Anomalocaris, which grabs the victim on the left side of the body and feeds to right side into the jaws. It then flexes the victim back and forth, inducing a weakness, which eventually caused the cuticle to crack.
G: I think you’ve cracked the case!
[fade out]

[Grissom walks past Catherine’s office where she is sitting at her desk with her head in her hands]
G: Catherine?
C: I’ve just had a call from some lawyer at the Discovery Institute. They are challenging our findings on Anomalocaris.
G: On what grounds?
C: They say that, as the arthropod cuticle is so complex and perfectly suited to its purpose, it had to be designed. And, since we cannot know the mind of the Designer, He could have made that particular cuticle act that way.
G: He?
C: Yeah, I noticed that. Anyhow, they also said that our dogmatic commitment to the materialist world view was closing our mind to other possibilities and was prejudicing the case against Anomalocaris.
G: What did you say?
C: I told them that they could shove their religious, anti-science claptrap right up their[bum bum - bum - bum bum. Whooooo are you? - Who? Who? - Who? Who?]


Naraoia sp. - Itself
Redlichia takooensis - Itself
Ogygopsis klotzi - Itself
Anomalocaris - Itself

Collins, D. (1996) The "evolution of Anomalocaris and its classification in the arthropod Class Dinocardia (nov.) and Order Radiodonta (nov.). Journal of Paleontology, v. 70, pp. 280-293.

Thursday, December 4, 2008

Me on TV

The Emu Bay Shale fossil location, on Kangaroo Island in South Australia is a Cambrian Lagerstatten - a site of exceptional preservation (the subject of a future blog entry). I did my PhD on the fossils from this site a while ago, and it is currently being studied by an international team led by the South Australian Museum and the University of New England.

Earlier this year a good friend of mine Paul Willis, another ex-palaeontologist and now reporter on the Australian Broadcasting Company’s Catalyst science program, did a story on the deposit. The story can be seen here. I'm not sure if it will play for international viewers, but at least there's a good cover shot of me at the South Australian Museum with a wierd exotic creature, and an Anomalocaris model!

I think Paul wanted to do the story just so that he could say “the world’s oldest turd” on national televation.

The trilobites and Anomalocaris fossils featured here were collected from the site featured in the story.

Early nervous system development

I think I’ve beaten PZ Myers to this one!

Scientists at the Brain Institute, and the School of Biomedical Sciences at the University of Queensland, look to have unlocked part of the gene-molecular interaction responsible for the formation of the neural tube. The neural tube is the first structure to develop in what will eventually become the central nervous system.

This is important because defects in the closure of the neural tube leads to some real nasty defects in the nervous system, such as spina bifida and even anencephaly.

The interaction in question is between Repulsive Guidance Molecule (RGMa) and the receptor protein Neogenin. The team experimented on zebrafish and clawed toad embryos by knocking out Neogenin. They found that this interrupted the proper formation of neural folds, which is the first stage in the development of neural tubes, subsequently affecting the closing of the neural fold.

Identifying one of the interactions involved in neural tube development will allow experimentation on how Folic Acid reduces the incidence of neural tube abnormalities. It has been known for some time that increasing the intake of Folic Acid by women before conception reduces the incidence of neural tube abnormalities, but little is known about the mechanisms involved.

Why is this on Ediacaran? Because the neural tube is of great significance to all us chordates (Yes, we too have Neogenin). And so a better understanding of the mechanisms behind neural tube formation can give us insights to the evolution of the Chordata.

Nigel Kee, Nicole Wilson, Melissa De Vries, DanaKai Bradford, Brian Key, and Helen M. Cooper (2008). Neogenin and RGMa Control Neural Tube Closure and Neuroepithelial Morphology by Regulating Cell Polarity. Journal of Neuroscience, 28(48):12643-12653.

Wednesday, December 3, 2008

I've been memed

Bugger, I’ve been memed.

Eamon Knight tagged me with the Six Things Meme. The rules are:

1. Link to the person who tagged you. [done]
2. Post the rules on your blog. [done]
3. Write six random things about yourself. [see below]
4. Tag six people at the end of your post and link to them. [umm, do I know 6 people that blog and have not been tagged?]
5. Let each person know they’ve been tagged and leave a comment on their blog. [see 4 above]
6. Let the tagger know when your entry is up. [Oh, I think I’ll do more that that . . .]

My Six Random Things:

1) I was born and raised in Swansea, South Wales. Hence I was hoping to get “Cambrian” as a blog name, but it was taken. Still “Ediacaran” is an acceptable second choice.

2) I have a tattoo. But I’m not telling where.

3) Eamon Knight‘s cat really, really liked me. Not, I suspect, Kizhe the Couch Czar. Probably pre-Kizhe. Easily freaked-out cats must see me as an easy mark.

4) I’m a Sagittarian. And to all the single women out there, don’t fall for all that astrology nonsense, Sagittarians are compatible with all other star signs (this one is anyway).

5) I’ve been on the Australian Broadcasting Company’s Catalyst program twice now. Adding all my time on screen together, I still recon that I’m a few short of my 15 minutes.

6) I was a foundation “Chris” at the University of Ediacara.

Tuesday, December 2, 2008

Diagenesis Blog

Check out the new Diagenesis blog. Jesse works on Ordovician faunas, which is a trifle recent but we shouldn't hold that against him!

PalaeoPorn 3

While I recuperate from a round the world trip the wrong way (left to right), here's some more Burgess. You know you want to . . .

It's a dirty job, but someone has to do it!

Anomalocaris jaw from the quarry

Stories of the extinction of Anomalocaris appear to be greatly exaggerated!

A Burgess trilobite with appendages, what I found at the quarry

Sunday, November 9, 2008

PalaeoPorn 2

As I'll be away for the next couple of weeks, this time PalaeoPorn has something different.

This is the world famous Burgess Shale in the Yoho National Park, British Columbia, Canada.

Palienation 2012

Palin for 2012! No. Really.

I think almost everyone would want Governor Palin to run in 2012.

The religious right want her because she's their kind of gal, and while she is a woman, it's the Vice President and close advisers that make all the decisions, right?

The moderate Republicans would want her to run because 2012 is probably a lost cause (unless something drastic happens) and so why waste a good candidate. Also, it'll be a sop to the christian right and, when the palienation of moderate America is complete, they can tell the christian right "we did it your way, it didn't work. Now lets go back to the centre."

The Democrats would want her to run because if she did, President Obama wouldn't need to campaign!

So Palianation 2012? Yes we can!

Tuesday, November 4, 2008

An introduction to the Ediacaran fauna

The Ediacaran fauna (pronounced edi-ak-ran) is a Precambrian (Neoproterozoic) assemblage, which existed from about 600 million years ago to approx 545 million years ago.

The fauna has now been found on all continents except Antarctica. However, the most important sites are: Namibia; Newfoundland & MacKenzie Mountains’ Canada, the White Sea Coast Russia; and the Flinders Ranges, South Australia.

One of the best localities and the place where the significance of the fauna was first recognised is here in South Australia. The name Ediacara comes from the site where the fossils were first recognised as Precambrian. Fossils were found in Namibia about 25 years earlier, but due to a mistake over the age and the fact that the finds were published in foreign language journals (German) their significance was not realized at the time.

Whilst the fauna has a world-wide distribution, it is important to note that there are significant differences in the make-up of the fauna at different localities. This is due, in the main, to environmental conditions. The Australian and Russian forms are similar and the rocks are indicative of a shallow water ecosystem. The Newfoundland forms contain decidedly different elements and the rocks are indicative of a deep water setting.

The fossils occur as depressions up into or extensions down from the bottom of thin quartzite beds. The fossils were formed by the covering of the muddy, biofilm covered, shallow sea floor, and the organisms on it, by mantling, thin sand bodies. Those organisms which where able to support the sand created depressions up into the overlying sand body. Those organisms which were either lying in or were forced into the mud by the sand, allowed sand to fill in the void left as they decayed (to produce downward extensions on the bottom of the sand body).

The majority of fossils are of rounded forms, reminiscent of jellyfish and in fact these were classified as jellyfish for a long time eg. Cyclomedusa (above), Mawsonites (left). (up to 35 cm across) Other forms included occasional 'sea-pen-like organisms (Pennatulacean colonial octocorals) which appear very similar to forms extant today (up to half a metre tall). A couple of possible annelids such as the large sheet-like form Dickinsonia (top) which looks like a flat pancake with segmentation, a gut and a definate head end (up to 75 cm long); and Spriggina which looks like a cross between a bristle worm and a trilobite (5 cm). A possible arthropod is also present, Parvancorina a recent specimen of which shows gills and possibly legs (3 cm).

A unique form is Tribrachidium (right), which as its name suggests is based on a tripartite body plan, but may well be some form of lophophore (similar to brachiopods and bryozoa)(3 cm).

It was thought that the fauna was dominated by the motile, free-swimming medusoids, which created a problem of preservation since medusoids do not, as a general rule spend a lot of time on the sea bed in the adult form. However it has shown that, whilst medusoid forms are represented, the vast majority of rounded forms are the anchors of sea-pens.

Modern sea-pens have a round, bulbous structure near the base of the organism which is highly muscled (seen in the middle of the disc on Charnodisucs at left). The organism uses this 'organ' to burrow into the soft muddy sediment and then as an anchor to hold the organism in place. During burial by the mantling sands, the stem of the 'sea-pen’ breaks, and the body of the 'sea-pen' collapses. Since the 'sea-pen is held up by hydrostatic pressure, the rip deflates the 'blade', the 'blade' becomes mixed with the sand, thus diminishing its preservation potential. The bulb, on the other hand, is already buried. In life the bulb is filled with water, so when the stem breaks away, the bulb fills with sand.

Since the underlying mud is approx. 80% water, as it dries out the thickness of the bed diminished to only a few cms, resulting in a flattened, rounded outline to the fossil. The various classifications on the 'medusoids' was due to surface ornamentation (ribs, concentric circles etc.), these are now thought to be the manifestation of muscle bands due to different degrees of decay before final 'molding'.

Thus the fauna has a decidedly benthonic bias, rather than being made up of free swiming forms as previously thought.

There are two main theories as to the affinities of the Ediacara fauna. One, originally put forward by Martin Glaessner is that most of the forms are related to modern forms, if not direct precursers. The other, proposed by Dolf Seilacher is that the Ediacaran fauna represents a unique bodyplan which arose early in metazoan evolution and became extinct before the Cambrian and thus all the forms within the fauna are members of a now extinct, separate phylum - the Vendozoa, with no connection to modern forms- or even Cambrian forms.

However, close examination of the fossils shows that many of the forms do indeed have a striking resemblance to Cambrian if not modern forms. Finds of 'sea-pen'-like organisms in the Burgess Shale (Thaumaptilon, which are very similar to Ediacaran forms appears to extend the range of such forms well into the Cambrian. Also, the form Kimberella can be probably placed within the Mollusca on structural and trace fossil grounds.

Thus several groups within the Ediacaran fauna exist today, and so the whole fauna did not become extinct. This is not to say that there are not some unique forms, there are, but the idea that they are all unique is overstepping things. My own opinion is that several groups of extant organisma can be traced back to the Ediacaran fauna. However, the origin of the metazoans is another matter. The Ediacaran fauna appears as a fully intergrated ecosystem with some quite advanced forms (eg. the colonial octocoral 'sea-pens'), so the question of origins has to be pushed back even farther, maybe as a consequence the late Proterozoic glaciation that ended approx 650 million years. Body fossil evidence will probably never be found, since they occur in meiofauna - too small to leave anything but chemical traces.

The various elements of the Ediacara fauna are united by one common character, none have any hard parts. There is no evidence of mineralisation in any fossil so far found. Thus the preservation of essentially 'soft bodied' organisms presented something of a quandary, especially as they are preserved in what is now quartzite.

It was thought that fossilization was due to a unique sedimentological facies, namely the ripple-topped sands mantling muds and that the fossils were constrained by the occurrence of this facies. However, the Ediacara Member in the Flinders Ranges contains 5 separate facies, ranging from thinly laminated silts to high energy, coarse sandstones, each of these facies if fossiliferous to one degree or another. Thus fossilization is not facies controlled, but occurs due to the interplay of a number of factors.

Amongst the factors which allowed the preservation of the Ediacaran fauna are (in no particular order): collagen, the lack of bioturbation , and the lack of predation.

The ability to produce collagen is important because collagen is relatively inert, strong and flexible. A collagen outer layer helped hold the organism together. It also allowed the organism to retain its shape when covered by the mantling sand to produce the fossils. Also, since collagen was a relatively new compound, the micro-community took a while to realize that collagen was a food source.

The reliance on passive adsorption of oxygen over the whole body meant that tissues had to be close to the surface in order to obtain oxygen by simple diffusion. This meant thin bodies. There is very little constraint to the size such organisms could reach, provided they stayed thin, hence half metre long 'flat' worms. However, flat, thin bodies are very bad at burrowing, which meant that vertical burrowing was virtually unknown during this period.

This meant that any organism that was buried was not disturbed, disrupted and ultimately destroyed by bioturbation (as it common today).

Since there were no hard parts about, predation was well nigh impossible, except possibly by disgorging some sort of dissolving fluid and sucking up the resultant gastronomic soup. But, definitely no chewing! Therefore, once the organism shuffled off to join the ranks of the choir immortal, it's mortal remains did just that - remained. They hung around on the surface, undisturbed for a considerable period of time, waiting for the mantling blanket of sand.

As was mentioned before, collagen was probably still a relatively novel compound at this time, so it was resistant to decay.

However, these conditions did not last. An interrelated series of events which included, increasing oxygen levels, the acquisition of mineralization capabilities, the rise of predation and the ability to produce a round cross-sectional body plan (by confining oxygen scavenging to certain parts of the body and using fluids to carry oxygen through the body) conducive to burrowing, soon demolished what was a pristine preservational environment. The so-called extinction of the Ediacaran fauna is IMHO largely illusionary for several reasons:
  • Of 7 cnidarian groups represented in the Ediacaran fauna, 4 appear to be ancestral to living taxa.
  • There is no close time control in respect of the supposed episode of extinction.
  • The disappearance of the fauna is largely due to the closure of a taphonomic or preservational 'window'.
  • The uppermost facies of this period throughout the world indicate a shallowing upward cycle, resulting in environments likely not conducive to preservation.

Saturday, November 1, 2008

Will the real Cambrian Explosion please stand up

OK, now I’m really pissed! No, it’s got nothing to do with the bottle of fine South Australian Red I’m soothing my pent up frustration with. It’s another bloody antievolution ‘expert’ mangling the Cambrian Explosion. Again!

Look. People. Let’s be clear about this. Please be specific when you are talking about the Cambrian Explosion. At least identify WHICH Cambrian Explosion you are talking about.

Cambrian Explosion One is the evolution and consolidation of a number of new body plans (disparity) which occurred over an extended period of time, and started well inside the Ediacaran. This was a true exploration of morphospace - groups boldly going where no group had gone before. Really.

Cambrian Explosion Two is the rapid expansion of the Cambrian fossil record. Which, while an evolutionary event, was primarily a biochemical event – namely the rapid take up of the idea that playing around with carbonate or phosphate mineralisation was right up the in the list of brilliant tactical maneuvers. Be it for digging burrows, chewing on everyone else, or stopping everyone else chewing on you. It was a diversification event – by comparison, exploring the local region of morphospace (boldly going where no group had gone before but within reasonable parameters, and we promise we’ll be back for dinner.)

Cambrian Explosion Two is to evolution what the microwave background radiation is to the Big Bang (kind of).

It’s the bit we get to play with after the major event.

So, the next time some antievolution 'expert' prattles on about the suddenness of Cambrian Explosion Two (and so Cambrian Explosion One was sudden), ask 'em WHICH Explosion they are on about, and do they now the difference between boldly going where no group has gone before, and swanning around the solar system?

Oh, and it’s a Wynns Coonawarra Cabernet Shiraz Merlot 2001. Thanks for asking.

PalaeoPorn 1

This is the type specimen of what I would later name Anomalocaris briggsi, in the field, 10 minutes after being exposed for the first time in about five hundred and nineteen million years. You couldn't wipe the smile of my face for the rest of that day! The coin is an Australian 20 cent piece, about the same size as a Canadian $2 coin. See below for a close up and a better guide to the size (the scale bar is 2 cm).

The AntiPalin

. She's smart, articulate and an atheist. She's the AntiPalin! Check out her youtube site.

And remember, people who think like the people who tried to get her banned also vote. So Vote!

From Pharyngula.

Friday, October 31, 2008

The reverse Bradley effect electoral wormhole warp in space/time phenomena

FirstDogontheMoon is an Australian cartoonist I really like - his work that is . . . we've never met - although we did talk on the phone and he seemed very nice . . . er, but anyhow, here by way of introduction, is FirstDogontheMoon's explanation of "the reverse Bradley effect electoral wormhole warp in space/time phenomena".

More FirstDog, including special standouts:

The Governor Palin How to Field Dress a Moose Commemorative US Election Tea Towel (19 September); and

The Death of Capitalism (8 October)

Monday, October 27, 2008

A moderate in the hand is worth two religious rights in George's bush

The GOP are in serious trouble due to some major tactical errors. One rationale for bringing the terrible Sarah Palin on board is obvious, Senator McCain was simply too liberal for many of the religious right, and their support was crumbling. However, bringing in a sop for the religious right simply drove off the moderates. And that's the real problem.

To explain. Say the vote is approximately McCain 50 : Obama 50 and perhaps 20% of McCain's vote is the religious right (that's 10 of his 50). Then say he loses those votes because of his wildly liberal views. Those votes are lost. Gone. They'll not vote for anyone more liberal than Senator McCain. The count is then McCain 40 : Obama 50. Senator Obama gets a 10 point lead.

Now, say we introduce the Palin factor. Back come your religious right, fervoured up, hoping for a McCain/Palin win, and praying for a swift McCain death (I kid you not!) However, away goes the moderate end of the support, the 20% who stuck with Senator McCain but can't stomach the rantings of the religious right.

So where does that leave Senator McCain? back at 40:50 right? Wrong. The problem for the GOP is that, while the moderate vote is lost to McCain, the votes themselves aren't lost. Unlike the religious right, the moderates still vote - but for Senator Obama! The count is now McCain 40 : Obama 60 - a 20 point spread for the same number of votes lost.

The GOP needs to bring 2 religious right votes for every moderate they loose, and I don't think they can do it.

Stand tall moderates, you vote is worth two religious right votes!

Sunday, October 26, 2008

The Spandrels of San Marco and the Anomalocaris Paradigm

The Spandrels of San Marco and the Panglossian Paradigm is one of my favourite science papers. As someone who accepts natural selection as a powerful evolutionary mechanism, but who considers that there are other, equally, or perhaps more, powerful mechanism out there, such as genetic drift, this paper resonated a lot with me. To summarise the paper (if you haven’t read it, please do), not everything that happens in evolution occurs because it was selected for. Like spandrels, things can happen as a consequence of other events. To summarise the summary, sh*t happens.

Here I’d like to develop that theme using Anomalocarus.

Anomalocaris was a torpedo-shaped, 1+ metre, top-line predator in the Early Cambrian oceans. It had a nasty set of jaws set in a circular mouth and a pair of muscular spiny appendages
hanging praying mantis-like from the head, and a pair of large bulbous eyes. It was a mean bugger. If the kids that burn the wings off insects had aquaria, this is what they’d want in it. We’re talking the king of the Cambrian. Nasty.

Big predators need big prey and Anomalocaris ate trilobites, big trilobites, big spiny trilobites. In this case, Redlichia. (see image. Scale bar at top = 1cm)

Think of Redlichia as having the style, sophistication, and armour plating, of an Abrams tank. Not the quickest trilobite around, not the most manoeuvrable, but not so much of a problem when, you’re up to 20 centimetres long, and the only thing that big enough to eat you is Anomalocaris, especially when the jaw elements of Anomalocaris were less strongly mineralised than Redlichia, AND, the jaw elements couldn’t actually bite together!

Hang on. If the jaws were less strongly mineralised, and didn’t even come together strongly, just how could Anomalocaris eat Redlichia?

Well we have evidence that Anomalocaris did indeed eat Redlichia – trilobite fossils with great wedge-shaped bite marks that had to have been made by Anomalocaris, and fossil poo of broken Redlichia fragments of a size that could only have been delivered by Anomalocaris (at least we haven’t found anything smaller with an appropriately pained expression). Anomalocaris was able to dine on Redlichia by exploiting a weakness in one of the most successful body parts ever to have evolved, the arthropod exoskeleton.

OK, a quick intro to arthropod exoskeleton

Arthropod exoskeleton gets its mechanical properties primarily from a bilayered construction, consisting primarily of a thin, usually mineralised, outer exocuticle, underlain by a thicker, unmineralised, endocuticle. Each of these brings a differing mechanical property to the exoskeleton. The hardened exocuticle is strong (and thus resistive to cracking) under compression (or being poked), but weak (and vulnerable to cracking) under tensional forces (or being stretched). By comparison, the softer, more pliant endocuticle is the opposite, weak under compression, but strong under tension. These properties combine to provide a greater level of protection against mechanical attack than either layer could alone, especially against normal predation, which pushes down, producing compressional stress on the exocutile, and causing the underlying endocuticle to stretch around the pressure, producing tensional stress on the endocuticle.

By varying the thickness and mineralization of the two layers, arthropods can produce a wide range of exoskeleton types, from stretchy elastic to hard rigid.

(There’s a lot more to arthropod cuticle, but that’s enough to be going on with.)

Ok, so how does this help Anomalocaris, and where is the weakness? Well, what Anomalocaris did was to attack from the side, reach over the top of the trilobite with its two appendages and grip the far edge of the trilobite, wedging it between the spines on the appendages. It then pushed the near side of the trilobite into its mouth and pinned the trilobite in its jaws somewhere between the near side and the middle of the body. Now comes the neat bit. Anomalocaris would then pull up with its frontal appendages (no doubt assisted by the large muscles in the head) and flex the trilobite - almost like trying to roll the far side of the trilobite around to the near side to make a tube. Then Anomalocaris would reverse the process. Flexing one way imparts compression stress on the exocuticle and tensional stress on the endocuticle and flexing the other way reverses the stresses so that the exocuticle is under tensional pressure and the endocuticle is under compression. And as strong as both are in one stress field, they are weak in the other field. Flexing back and forth quickly induces fractures in the cuticle, which propagate and finally result in failure, allowing the Anomalocaris to break off large chunks of juicy trilobite.

You can mimic this process using a credit card (preferably an expired one). It’s impossible to break a credit card by poking at it with your fingers. But, if you grip it in both hands by the short edges and flex it back and forth, a line of weakness quickly forms, as plastic is weak in tension and the stretching motion quickly weakens the card. Pretty soon you can break the card as a crack propagates along the line of folding. Substitute appendages and mouth for your right and left hands and this is essentially what Anomalocaris does.

All well and good, but what has all this to do with evolution and spandrels?

Well, the thing about trilobites is that, as arthropods, especially arthropods with armour plating, the only way they can grow is by moulting.

Just as crabs do today, trilobites had to escape from the exoskeleton they were living in order to grow. They would emerge soft and squidgy, pump themselves up to the new size and then harden the new exoskeleton.

Prior to moulting, arthropods made changes to the cuticle that made it brittle and easy to crack. To further help the moulting process in trilobites, there were a series on lines of weakness, called suture lines. These were the first things to break once moulting started, and so aided the process. They can be seen in the Estangia photo at the top left of this blog. The crescent-shaped structures on the head, either side of the central bulbous glabella, are the eyes. The line running behind the eye and continuing on to the back of the head, is a facial suture. It continues from the top of the eye to the outer margin of the head – best seen on the left side of Estangia, where the whole area of the head outside of the suture line has been displaced (called the ‘free cheek’ for this reason). This shows that the specimen is a moult. Once the suture lines had parted, the trilobite would exit the old exoskeleton through the head region.

The reasons for suture lines around the eyes are obvious. It was important to ensure that the eyes were easily released during moulting, as the trilobite was vulnerable, and needed the eyes free to keep watch.

However, moulting is a hit and miss affair. Problems can occur. For example the facial sutures may not break easily. Trilobites having difficulty moulting would be in trouble, after all, it’s not like they could ask for help! A trilobite thrashing around on the sea bed trying to moult would draw attention to itself at a very vunerable time.

The problem for big Early Cambrian trilobites like Redlichia is that they had limited flexibility (curling head to toe). This meant limited options should anything go wrong with the moulting process. And things went wrong - I collected a Redlichia specimen where the left free cheek was upside down, the right was implanted into the sediment at 90 degrees, and the body has split into three parts. It had either undergone a horrendous moult, or had just had the best sex of its life!

So anything that assisted the moulding process would be advantageous

The ability to enrol the body (curling the body so that the head tries and meet the tail, with the legs tucked in between), even part way, would clearly aid moulting as it would stretch, and put pressure on, the exoskeleton and suture lines. So its of no surprise that by the end of the Cambrian all trilobites could flex to a fair degree, and some could almost touch head to tail. Estangia was well on the way to being able to do it in the Early Cambrian.

Enrolling has such an obvious benefit to trilobites generally that it isn’t surprising that it is a common, in fact pretty much ubiquitous, feature of trilobite after the Cambrian (the group that Redlichia belonged to never made it out of the Cambrian). Even the itty-bitty trilobites that Anomalocaris wouldn’t be seen dead eating (or rather would be seen dead as small trilobites wouldn’t provide enough energy to warrant the chase. Imagine a whale eating krill, one at a time!) It’s clear then that enrollment was probably selected for as an aid to moulting as pretty much all trilobites after the Cambrian could do it to a significant degree.

But, and here’s the kicker (finally), enrollment – even partial enrollment achieved by some Cambrian trilobites – negates the Anomalocarus predation method.

A curved trilobite cannot be flexed back and forth like a relatively flat trilobite can. To go back to the credit card analogy, imagine trying to flex a curved credit card.

Clearly enrolling didn’t evolve as a defence mechanism because the early, non-complete enrollement forms still allowed access to the softer juicier bits, and also would not have protected against adverse environments either. Neither could its common occurrence be put down to protection against Anomalocaris predation, as it occurs across the range of trilobites, even the itty-bitty ones.

The most obvious reason for enrollment in most, if not all, trilobites after the Cambrian, is that it aided in moulting and not defence, and not defence against Anomalocaris.

But it was the death-knell for Anomalocaris.

Anomalocaris was crucified on the spandrels of San Marco.

Sh*t happens.

Gould, S. J. and Lewontin, R. C., (1979) The Spandrels of San Marco and the Panglossian Paradigm: A Critique Of The Adaptationist Programme. Proceedings Of The Royal Society of London, Series B, Vol. 205, No. 1161, pp. 581-598.