Pikaia is most primitive vertebrate known

 

Yesterday I was talking to one of my colleagues and she asked me if I'd heard the latest news about the Burgess Shale. I confessed ignorance so she told me that scientists had just discovered a primitive vertebrate fossil in the Burgess Shale.

Hmmm ... I was aware of possible primitive vertebrates ("Craniates" is a better term) in the deposits from China (e.g. Myllokunmingia) but I'd never heard of a vertebrate fossil in the Burgess Shale so I thought I'd check out the press release.

It's from my university!!! [Pikaia is most primitive vertebrate known]

Researchers from the University of Toronto, the Royal Ontario Museum (ROM) and the University of Cambridge have confirmed that a 505 million-year-old creature, found only in the Burgess Shale fossil beds in Canada’s Yoho National Park, is the most primitive known vertebrate and therefore the ancestor of all descendant vertebrates, including humans.

The research team’s analysis proves the extinct Pikaia gracilens is the most primitive member of the chordate family, the group of animals that today includes fish, amphibians, birds, reptiles and mammals. Their study is based on the analysis of 114 specimens and is published in the British scientific journal Biological Reviews.

The headline is wrong. Pikaia is a chordate but not a vertebrate as the quotations from the researchers make clear. The press release from Cambridge is only a bit better [Humans' ancient ancestor revealed - as a 505 million-year-old 'eel']

“The discovery of myomeres is the smoking gun that we have long been seeking,” said the study’s lead author, Professor Simon Conway Morris of the University of Cambridge. “Now with myomeres, a nerve chord, a notochord and a vascular system all identified, this study clearly places Pikaia as the planet’s most primitive chordate. So, next time we put the family photograph on the mantle-piece, there in the background will be Pikaia."

Furthermore, this really isn't news. Pikaia was featured in Stephen Jay Gould's book Wonderful Life published in 1989. Even then, Pikaia gracilens was thought to be a chordate similar in broad features to the cephalochordate (non-vertebrate chordate) Amphioxus. This classification was attributed to Simon Conway Morris in 1979. The Wikipedia article [Pikaia] points out that this classification was not universally accepted.

The important points are: (1) that Pikaia is a primitive chordate but not a primitive vertebrate and the press release is just dead wrong about that and, (2) this is old news.

BTW, is Conway-Morris right about Pikaia being the oldest chordate? I thought the fossils from China were older and some of those might even be vertebrates. If that's true then Pikaia lived after the divergence of cephalochordates and vertebrates and it's not even remotely possible that it's our ancestor.

There ought to be a new rule about press releases. Each one should have a statement at the end saying the the press release has been read by the authors of the study and they approve its content.

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Conway Morris, S. and Caron, J-B (2012) Pikaia gracilens Walcott, a stem-group chordate from the Middle Cambrian of British Columbia. Biological Reviews. Article first published online: 4 MAR 2012 [doi: 10.1111/j.1469-185X.2012.00220.x]

Redshirting: Holding kids back from kindergarten

 
Until a few minutes ago I had never heard of "redshirting" although I was familiar with the concept. Some parents want to hold their children back from kindergarten (or have them repeat kindergarten) so they will be older and more mature than the other students in their class. A school teacher advised us to do that for one of our children but we adamantly refused. Best decision we ever made concerning the education of our children.

When I was growing up the best and brightest students were allowed to skip a grade if they were doing well. (I took grades three and four in a single year.) It was a mark of achievement to be among the youngest in your class, especially if you were doing as well, or better, than the other students. On the other hand, if you were the oldest in the class then your achievements were discounted because you had an intrinsic advantage.

When I was growing up it would have been psychologically devastating to be the oldest student in the class and not be at the top of the class academically. (That's partly because the oldest students were usually the ones who had flunked a grade.) I wonder if parents who hold their children back have ever thought about the potential negative consequences? What happens if your child is just average and redshirting doesn't work?

Here's a 60 Minutes segment on redshirting. It features two people from the University of Toronto: writer Malcolm Gladwell (B.A. 1984, Trinity College) and economist Elizabeth Dhuey a professor in the Department of Management.

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Carnival of Evolution #45

 

This month's Carnival of Evolution (45th version) is hosted by Adrian, a Canadian from Edmonton, Alberta who blogs at Splendor Awaits: Carnival of Evolution #45.

Here at last is the Carnival of Evolution. Because there were so few bug-based submissions, I had to change my plans and think of a new approach. I decided this would be a good time to try the new Google Presentation. This plays for me in the latest edition of Firefox, let me know how it works on your browser.

On with the Carnival! It’s awkward, a bit goofy and tongue-in-cheeky, but it does have bugs.

The next Carnival of Evolution (April) needs a host. Contact Bjørn Østman at Carnival of Evolution if you want to volunteer. Meanwhile, you can submit your articles for next month's carnival at Carnival of Evolution.

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We Are Stardust

Helena Curtis was an amazing writer. She's famous for her introductory biology textbook published by Worth beginning in 1968 [Good Science Writers: Helena Curtis]. Here's the opening paragraphs.

Our universe began, according to current theory, with an explosion that filled all space, with every particle of matter hurled away from every other particle. The temperature at the time of the explosion—some 10 to 20 billion years ago—was about 100,000000000 degrees Celsius (10¹¹ °C). At this temperature, not even atoms could hold together; all matter was in the form of subatomic, elementary particles. Moving at enormous velocities, even those particles had fleeting lives. Colliding with great force, they annihilated one another, creating new particles and releasing great energy.

As the universe cooled, two types of stable particles, previously present only in relatively small amounts, began to assemble. (By this time, several hundred thousand years after the "big bang" is believed to have taken place, the temperature had dropped to a mere 2500°C, about the temperature of white-hot wire in an incandescent light bulb.) These particles—protons and neutrons—are very heavy as subatomic particles go. Held together by forces that are still incompletely understood, they formed the central cores, or nuclei, of atoms. These nuclei, with their positively charged protons, attracted small, light, negatively charged particles—electrons—which moved rapidly around them. Thus, atoms came into being.

It is from these atoms—blown apart, formed, and re-formed over the course of several billion years—that all the stars and planets of our universe are formed, including our particular star and planet. And it is from the atoms present on this planet that living systems assembled themselves and evolved. Each atom in our own bodies had its origin in that enormous explosion 10 to 20 billion years ago. You and I are flesh and blood, but we are also stardust.

Neil DeGrasse Tyson tops that in his spontaneous answer to the question, "What is the most astounding fact you can share with us about the Universe?"


If you're going to sing "we are stardust" then you can't do it any better than this group. The song was written by Joni Mitchell (another Canadian) but her version is not as good.

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[Hat Tip: Phil Plait of Bad Astronomy: Neil Tyson’s most astounding fact.]

Who Is This Man?

 

I saw this portrait in the Huntington Library in San Marino (near Pasedena) California, USA. This man was the friend of a kite flyer, a pottery maker, and Erasmus Darwin. One of Ms. Sandwalk's direct ancestors worked for him.

He's very famous. You'll recognize the name instantly even if you don't recognize his face. Who is he?

I'll keep the comments invisible for 24 hours so you can post your guesses.

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Monday's Molecule #160

 

This is a very important molecule for some species. It's important to me, for example, because I worked with it in an undergraduate research project forty-nine many years ago.

UPDATE: The original structure was missing a methyl group at the bottom right. This has now been corrected.

Identify the molecule—the common name will do but make sure you get it right because there are quite a few similar molecules. You must also say why it's important for some species.

Post your answer in the comments. I'll hold off releasing any comments for 24 hours. The first one with the correct answer wins. I will only post correct answers to avoid embarrassment.

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your comment.)

Some past winners are from distant lands so their chances of taking up my offer of a free lunch are slim. (That's why I can afford to do this!)

In order to win you must post your correct name. Anonymous and pseudoanonymous commenters can't win the free lunch.

Winners will have to contact me by email to arrange a lunch date.

Comments are invisable for 24 hours. Comments are now open.

UPDATE: The molecule is a gibberellin-like molecule. It was intended to be gibberellin GA1 but I left off a methyl group. This is similar to Monday's Molecule #102 (gibberellin GA3). Defects in one of the genes for gibberellin GA1 synthesis gave rise to the tall/short phenotype studied by Gregor Mendel [Mendel's Stem Length Gene (Le)]. Gibberellin GA1 was one of the molecules synthesized by Elias James Corey, winner of the Nobel Prize in Chemistry 1990. The winner this week is Albi Celaj.

Winners
Nov. 2009: Jason Oakley, Alex Ling
Oct. 17: Bill Chaney, Roger Fan
Oct. 24: DK
Oct. 31: Joseph C. Somody
Nov. 7: Jason Oakley
Nov. 15: Thomas Ferraro, Vipulan Vigneswaran
Nov. 21: Vipulan Vigneswaran (honorary mention to Raul A. Félix de Sousa)
Nov. 28: Philip Rodger
Dec. 5: 凌嘉誠 (Alex Ling)
Dec. 12: Bill Chaney
Dec. 19: Joseph C. Somody
Jan. 9: Dima Klenchin
Jan. 23: David Schuller
Jan. 30: Peter Monaghan
Feb. 7: Thomas Ferraro, Charles Motraghi
Feb. 13: Joseph C. Somody

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Rosie Redfield Talks About Arsenic

 
Way to go Rosie! We'll soon turn you into a biochemist! I love it when you say the textbooks are still right.

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The God Helmet: Your Brain on Religion

 

The Centre for Inquiry (Toronto) is trying to get back on track after CFI fired two National Executive Directors and the director of CFI Ontario/Toronto. We've lost our facility on Beverley Street so we now have to meet at various other locations in different parts of the city.

The Freethinkers Skeptics and Atheists (Free[SAY]) at York University have organized a talk on "The God Helmet: Your Brain on Religion" featuring Michael Persinger and his God Helmet. Here's an excerpt from the Wikipedia article.

During the 1980s he stimulated people's temporal lobes artificially with a weak magnetic field to see if he could induce a religious state (see God helmet). He claimed that the field could produce the sensation of "an ethereal presence in the room". This research has received wide coverage in the media, with high profile visitors to Persinger's lab Susan Blackmore and Richard Dawkins reporting positive[8] and negative[9] results respectively.

The only published attempt, by a research group in Sweden, to replicate these effects failed to do so and concluded that subjects' reports correlated with their personality characteristics and suggestibility. They also criticised Persinger for insufficient double-blinding.[10] Persinger responded that the Swedish group had an incorrect computer setup,[11] a claim that the Swedish group dispute,[12] and that many of his previous experiments were indeed carried out double-blind,[13] although the Swedish group have also disputed this.[12]

Persinger is also famous for suggesting that "extremely low-frequency (ELF) electromagnetic waves may be able to carry telepathic and clairvoyant information" and for his "1975 Tectonic Strain Theory (TST) of how geophysical variables may correlate with sightings of unidentified flying objects (UFOs) or Marian apparitions." He also claims that women are far more susceptible to his God Helmet than men [Evolution Makes Women Stupid].

To my great embarrassment Michael Persinger won the contest for TV Ontario's Best Lecturer in 2007.

Here's your chance to meet Michael Persinger on Friday March 9, 2012 at York University. The Centre for Inquiry is co-sponsoring the event.

What if we could recreate a religious experience by simply flipping a switch in the brain? What if we could produce the feeling that someone or something is watching over us on demand? According to neuroscientific research conducted with The God Helmet, this may be possible.

The God Helmet, invented by Stanley Koren and used primarily by Dr. Michael Persinger, has forced us to reconsider the neurological basis of religion in the brain. The headgear is controversial because when electromagnetic waves are sent through a subject's temporal lobe, it can create the feeling of a religious experience, or a sense of belonging. “We basically imitate what happens within the brain itself during a mystical experience,” says Dr. Persinger.

In this engaging lecture with guest speakers Trevor Carniello and Dr. Michael Persinger, learn about how The God Helmet works and discover the origin of religious experiences in the brain. Join us in this exclusive opportunity to be able to ask Dr. Persinger questions and find answers to your curiosities about God, the brain and religion.

The lecture takes place on Friday, March 9th at York University. Tickets are available at freesay.wordpress.com. This event is brought to you by Free[SAY]: Freethinkers, Skeptics and Atheists at York in collaboration with the Center For Inquiry.

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Do Human Races Exist?

This is a question that's come up many times in the blogosphere. My own answer is "yes," humans races/populations/demes/subspecies do exist.

Human Races Populations
Is Race a Biological Concept?
Genetically Speaking All Races Are Equal
Changing Your Mind: Maybe Human Races Do Exist After All
Matt Nisbet Asks an Embarrassing Question
Genetics and Race
Greg Laden on "Race" (Again)
Anne Wojcicki's Politically Correct View of Race
The Problem of Race .... Again
Human Races

Davey Jones (1945-2012)

 
Davey Jones of the Monkees died yesterday. He was 66 yeas old. Here he is singing Daydream Believer, a song that hit #1 in the USA in December 1967.

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Exam Question #7

 
Today is the day of the midterm test in my course on molecular evolution. Here's one of the possible question on the test. Almost every student should get full marks on this one.

Imagine that a new mutation gives rise to a beneficial allele with a selection coefficient of 0.1 (s = 0.1) . What is the normal fate of this allele in a population of 10,000 individuals? Explain your answer.

Sandwalk readers should try and put this selection coefficient into perspective. It's probably at the high end for new beneficial alleles. What this means is that most adaptive explanations need to postulate a significant benefit to each individual in order to make the probability of fixation come out to some reasonable number.

Exam Question #1
Exam Question #2
Exam Question #3
Exam Question #4
Exam Question #5
Exam Question #6

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Exam Question #6

 
This is an easy question. Here are the others: Exam Question #1, Exam Question #2, Exam Question #3, Exam Question #4, Exam Question #5.

To a first approximation, the rate of fixation of neutral alleles in a population is independent of effective population size. Why?

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Exam Question #5

 
Did you try and answer Exam Question #1, Exam Question #2, Exam Question #3 or Exam Question #4? Were they too hard? Try this one.

Steven Pinker is an evolutionary psychologist at Harvard. He wrote ...

Are we still evolving? Biologically, probably not much. Evolution has no momentum, so we will not turn into the creepy bloat-heads of science fiction. The modern human condition is not conducive to real evolution either. We infest the whole habitable and not-so-habitable earth, migrate at will, and zigzag from lifestyle to lifestyle. This makes us a nebulous, moving target for natural selection.

What definition of evolution do you think he has in mind? Is he correct?

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Exam Question #4

 
Now that you've tried Exam Question #1, Exam Question #2, and Exam Question #3, let's see how you do with this one.

Many evolutionary biologists think that population genetics is the key concept in understanding evolution but biology students often complete several years of courses without ever learning about effective population sizes, mutations rates and the importance of random genetic drift. Why? Is it because population genetics is not a necessary key concept in evolution?

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A "Simple" Argument for Intelligent Design Creationism

 
Once again, it's time to remind people of a famous quotation by Isaac Asimov—a biochemist— from his 1981 essay, The “Threat” of Creationism [see Bill Dembski, Isaac Asimov, and The Second Law of Thermodynamics].

Creationists have learned enough scientific terminology to use it in their attempts to disprove evolution. They do this in numerous ways, but the most common example, at least in the mail I receive is the repeated assertion that the second law of thermodynamics demonstrates the evolutionary process to be impossible.

In kindergarten terms, the second law of thermodynamics says that all spontaneous change is in the direction of increasing disorder—that is, in a "downhill" direction. There can be no spontaneous buildup of the complex from the simple, therefore, because that would be moving "uphill." According to the creationists argument, since, by the evolutionary process, complex forms of life evolve from simple forms, that process defies the second law, so creationism must be true.

Such an argument implies that this clearly visible fallacy is somehow invisible to scientists, who must therefore be flying in the face of the second law through sheer perversity. Scientists, however, do know about the second law and they are not blind. It's just that an argument based on kindergarten terms is suitable only for kindergartens. [my emphasis - LAM]

Now, let's look at this video from: Are You Looking for the Simplest and Clearest Argument for Intelligent Design?]. Keep in mind that one definition of a "simple" argument is one that is suitable for kindergarten students (and IDiots).



This video was posted on the leading IDiot blog Evolution News & Views. It tells us a lot about the quality of their science and their commitment to truth.

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