UPDATE:  SOLVED at 1:49 CDT by Alejandro

Look at us, starting a new riddle cycle off with a bang.  As Tom mentioned in this post, we are able to offer a really cool prize from A&E to the person who solves this riddle.  Here’s a link to the Amazon page, along with the one in the side bar, if you want to check it out.  Don’t spend too much time looking it over – the winner is the first person who solves the riddle!

For clarification, this special prize riddle will work exactly like the weekly riddles.  The riddle is open to everybody; I will be in the comments for feedback; the winner gets his/her name on the list for the next bonus riddle; the winner chooses the subject of my next blog post (Monday’s); the winner is the first person who solves the riddle; and Tom has the final say in any controversy.

Are you ready to riddle?  Ladies and gentlemen, start your engines:

The answer to today’s riddle is a thing.

It exists in the real world.

This thing really lives up to its name.

In order not to “understate” an important characteristic of this thing, you have to learn to compensate.

Sometimes it’s visible to the unaided eye; usually it’s not.

All things considered, today’s answer is on the chilly side.

Today’s answer fits into several categories, one of which is quite rare.

It appears ready to move on to its next incarnation.

…

Finis!  I know you have the answer, so hurry over to the comments and claim that amazing prize.

Everybody is eligible to win, so good luck.

The art of intimidation.

David Dobbs has a link roundup and commentary on what’s been going down with l’affaire Hauser. It doesn’t look good for Hauser et al., though it seems that the downfall was precipitated ultimately from within if press reports are to be believed. Part of the issue here seems to be that there’s a level of opacity in the scientific process, and you have to trust the scientists themselves over the short term. Over the long term the system of science and its general culture tends to self-correct, at least in the natural sciences, but over the long term careers can rise and fall, and science is produced by human beings. We know that science is possible, it’s been done for at least a few centuries even with the most constrained definitions, but we also know that it isn’t necessarily entailed by the existence of any complex society. A particular set of contingent conditions need to come together to allow for its emergence and perpetuation. So it’s all fine and good to observe that science as a system self-corrects, but without the individual incentives and institutional checks & balances it may never have a chance to flower.

This brings me to Dobbs’ comment about more “open science”:

One worry about more open review — which I can relate to as a journalist — is that one’s ideas get opened up and spread around before publication. This raises worries about ownership and priority and credit, worries that are reasonable, or at least hard to resist, in a culture that especially prizes and rewards these things, and which bases tenure, not to mention fame and prestige and all the accompanying goodies, on breaking the big theory or story. Science in that way closely parallels journalism.

Others argue that our emphasis on individual credit overlooks the collaborative nature of science to start with, and that a more honest approach (in a couple sense of the term) is to share data far earlier in the process. Such open science, the argument goes, would a) let many eyes mine the data so we get more out of it, b) reduce duplication of efforts, and c) serve as a constant check against everything from misreading data to fabricating it.

As the production and transmission of information becomes more “transparent” due to the nature of communication technology I wonder if concerns about ownership will abate, simply because transparency will allow for better reconstruction of the chain of creation and so implied ownership. This may not suffice for patents, but when it comes to scientific glory where reputation and not money is at stake, it may be good enough.

My latest hosted episode of Point of Inquiry is now up, and you can download it to your podcast player or stream it here. The show is an interview with Alexander Zaitchik, author of the new book Common Nonsense: Glenn Beck and the Triumph of Ignorance.

Here’s the show write-up:

This week, the scope of Point of Inquiry expands to include politics and more particularly, the fount of misinformation that is Glenn Beck of Fox News. This TV and radio personality is ushering in a new reign of ignorance in our national discourse—and even has the gall to liken his efforts to those of Martin Luther King, Jr.

But investigative journalist Alexander Zaitchick has pinned Beck to a wall with his new book Common Nonsense: Glenn Beck and the Triumph of Ignorance. He’s even provoked Beck into denouncing him for practicing “despicable, yellow journalism.” Coming from Beck, that’s a compliment.

So tune in to learn more about how Beck has become a new icon of American irrationality—and just general cluelessness.

Alex Zaitchik is a freelance journalist living in Brooklyn, New York. He’s contributed to Salon.com, The Nation, Wired, and many other distinguished publications. In the course of his career he has reported from locations ranging from Miami to Moscow, from Prague to Mexico City—and Common Nonsense: Glenn Beck and the Triumph of Ignorance is his first book.

Again, you can stream the show here, and the website is here.

Last Caturday, I posted a picture of my cat relaxing a little too well.

This shows a slightly different side to her:

That picture, taken by my brother-in-law Chris, is somewhat more accurate. For some reason, she hates him (and his son Derek even more). She rears back, spits, hisses, and generally makes terrifying guttural noises. It’s really funny.

Chris is an amazing photographer. You should take a look at his stuff!

News

Can autism be diagnosed with a brain scan? The lead author tells the Guardian that the test will be 90% accurate. No, says Carl Heneghan later in the Guardian – the actual chances that someone with a positive result would have autism is 4.5%, or around 1 in 22. The authors reply in the comments, and Heneghan replies back. Meanwhile, Dorothy Bishop discusses why it’s actually very difficult to set up a screening test.

Resistance to resistance is futile. Antibiotic-resistant bacteria carrying a gene called NDM-1 can shrug off all but two of our antibiotics, leading some scientists to warn about the end of the antibiotic era. Maryn McKenna has the best analysis at Superbug, while Sarah Boseley reports in the Guardian.

Harvard psychologist Marc Hauser is taking a year’s leave, amid talk of possible scientific misconduct. David Dobbs has the best overview of the events with tons of great links to other pieces. Nature, however, nailed the headline: Harvard morality researcher investigated for scientific misconduct

“Orangutans use mime to make themselves understood,” writes Ian Sample in the Guardian. 80 Beats sums up the story with some of the messages you can expect.

This is incredible. Photosynthetic algae have been found inside the cells of a “solar salamander”. Anna Petherick has the news at Nature.

Just… what? Virology Journal retracts a paper “speculating that a woman described in the Bible as being “cured by our Lord Jesus Christ” had flu”. Ivan Oransky’s post on the subject is pure gold, from the line “The authors of the original source material — Mark, Matthew and Luke — could not be reached” to the gripe from the paper’s author saying that he’s appalled that “so many comments were made outside the scope of the journal” rather than in letters to the editors. Heaven forfend.

More after the jump…

Russians are more likely to brood than Americans but less likely to get depressed as result. Jonah Lehrer explains why. Hint: it’s not because they’re secretly happy at inflicting the world’s most depressing literature on everyone else…

Knock out an anti-cancer gene in mice; gain the ability to regenerate limbs. Tina Hesman Saey reports in Wired.

I can’t believe the journalist didn’t pick this up: “Researchers report that a spinal fluid test can be 100 percent accurate in identifying patients with significant memory loss who are on their way to developing Alzheimer’s disease.” Paul Raeburn calls the NYT out on the Knight Science Journalism Tracker.

The Splintered Mind has a great post on Cotard delusion, an endlessly fascinating condition where people believe that they are dead.

The H1N1 pandemic is officially over as the WHO downgrades from Phase 6. Surely everyone will be happy, right? Right?

“Hanging is a frighteningly efficient way of ending a life, as executioners can attest and suicides cannot, but surprisingly, we’re still not sure how it causes death,” says Vaughan Bell.

Bristol scientists are developing software to fingerprint (finprint, surely) every great white shark in the world.

In Zoologger, Michael Marshall discusses the world’s most fecund vertebrate. No, it’s not Kerry Katona.

“As warming intensifies, scientists warn, the oxygen content of oceans across the planet could be more and more diminished, with serious consequences for the future of fish and other sea life.” Carl Zimmer talks about the doom that awaits as the oceans run out of oxygen.

Impala, tsessebe, zebra and wildebeest all respond to the alarm calls of baboons, says Matt Soniak

A thoughtful post by PalMD on a healthier attitude towards medical mistakes has spurred some equally thoughtful comments

The latest search for genetic variants that underlie personality differences has come up empty. The Neurocritic dissects the study while the ever-erudite Jonah Lehrer discusses the results in the context of Hamlet.

Guantanamo Bay: torture camp and, er, ecological research centre? A really nice photo-feature from Discover explains the biological allure of the site.

“Ruff” means “Hands off my bone” while “Ruff” means “Get away from me”. Jason Goldman blogs about the meaning of dog growls.

Is the mind like a spreadsheet or a search engine? Melody Dye answers over at Child’s Play.

Stepping away from your computer? Why not help to find a pulsar? These folks did.

Hey, good news! Gray wolves aren’t endangered any mor… oh never mind.

The top 10 lost amphibians, featured in the Guardian. They’re probably extinct. Or behind the sofa.

Heh/wow

“Warning: This article is basically just a press release, copied and pasted.” These journalism warning labels by Tom Scott are incredible.

Life speeded up: the BBC has put together a collection of timelapse videos from its natural history collection.

A diver gets mugged by an octopus, who steals its camera. He gives chase and then takes the octopus for a ride on the end of his speargun. All of it gets captured on video.

The Fastest Claw in the West is probably my favourite David Attenborough documentary of all time. I remember tuning in expecting to watch something about cheetahs. I got something far better – mantis shrimps. The whole thing is now on YouTube.

New monkey species already looks scared. It has every right to.

Carl Zimmer, via John Pavlus, captions every New Yorker cartoon for all time.

Vaughan Bell diagnoses Miley Cyrus’s ex with borderline personality disorder based on her song lyrics

Pollinators in action – great photography by Alex Wild.

The curious case of Wanky Balls.

The electric vaccine gun safeguards health, while allowing you to be macho. Unsurprisingly, the military likes it.

“Well, it’s not cancer. It’s a pea plant.”

This may be the worst pun I’ve ever written…

Journalism/blogging/internet

At the National Association of Science Writers, Tabitha Powledge asks if the future of science publishing depends on the future of science blogging? She deftly sums up various recent developments in the science blogosphere and charmingly credits Discover’s bloggers as “the most universally praised group of science bloggers”

Bora Zivkovic has another epic overview of the emerging suite of science blogging networks

Do open blogging networks threaten brands? John Rennie explores the question in two excellent posts and makes great points about the value of selective recruitment and the problems that remain.

Colin Schultz covers a new study about how science bloggers diversify the news rather than create an echo-chamber, while David Dobbs expands on the theme by looking at the Marc Hauser case.

Apparently the BBC has a strategy for linking out to more external sites, and plans to do more of this by 2013. They’re just not getting it, but it’s nice to see them flirting with relevance.

Razor-sharp commentary from Alice Bell on the myth of scientific literacy, and why it’s meaningless to just call for more of it.

Four reasons why young journalists should blog – this is old news but worth repeating

“The social network of a reader is quickly becoming their personalized news wire; fact, 75% of news consumed online is through shared news from social networking sites or e-mail.” Vadim Lavrusik reports in Mashable.

“Just like reading a novel.” Vivienne Raper lets a “member of the public” loose on my blog and 4 others

Sean Carroll has a diva moment and storms off the set of a bunk “science” show: a warning to all those with starry-eyed visions of a TV career.

Delene Beeland discusses life as a freelancer

I love this by film from Will Hoffman and Daniel Mercadante for WNYC’s Radiolab to accompany this week’s segment entitled Words:

One of the podcasts I subscribe to is Thinking Allowed from Radio 4. The most recent one was on the role which robots are envisaged to play in the future of Japan:

Also, the rise of the ‘fembot’. The Japanese government is investing billions in the development of robotic technology. They think the robot will do for the 21st century economy what the automobile did for the 20th. However, Jennifer Robertson thinks that as female robots are developed to perform some of the functions traditionally performed by women, it bodes ill for the future of Japanese society.

The guest was very negative about Japan’s plan to substitute robots for immigrants. Basically, she perceived that there was a risk that the Japanese were going to turn into technologically enabled inward-looking xenophobes, closing themselves off to the rest of the world and interacting only with their robot minions. If so, it’s their right as a nation to do so, and I don’t see why all nations should adopt the same policies in regards to globalization. It isn’t as if Japan’s Human Development Index was similar to that of North Korea.

Though science fiction has a generally bad track record as prediction, I couldn’t help but think of Isaac Asimov’s Spacer society of Solaria, from his Robot Series. There’s already a fair amount of media reports about antisocial personality disorders becoming very common in Japan, the sort of stuff that Asimov describes as normal on Solaria. Here is Wikipedia description of the Spacer worlds, of which Solaria was the most extreme case:

In Isaac Asimov’s Foundation/Empire/Robot series, the Spacers were the first humans to emigrate to space. About a millennium thereafter, they severed political ties with Earth, and embraced low population growth and extreme longevity (with lifespans reaching 400 years) as a means for a high standard of living, in combination with using large numbers of robots as servants. At the same time, they also became militarily dominant over Earth.

In many ways the Spacers, and what Japan aims to become, seems to be the realization of what the ZPG movement was pushing for in the 1970s. I’m moderately skeptical that they can pull it off as a practical matter, projections of the feasibility of humanoid robots have been overly optimistic for decades, but it would be an interesting development for a nation which prides itself on its peculiar distinctiveness to be the first to “merge” man and machine into a social ecology.

Image Credit: Wikimedia

Most readers of this weblog are aware that the United States is in a mission of “nation building” in Afghanistan. I know that we probably deny that, but that’s what it is. Going through Google data explorer I’m struck by what an exceptional nation we’ve decided to intervene in. Below is a chart which has infant mortality rate on the y-axis and life expectancy on the x-axis. I’ve allowed the bubbles to be defined by their regions in terms of color, and labelled the South & Central Asian nations to give a sense of the change in vital statistics for the “peers” of Afghanistan over the past generation. Observe that Sub-Saharan Africa is pulling away from Afghanistan in the last 10 years!

Science fiction movies and TV shows are perpetually trying to see through things: Everyone from Superman to last year’s KITT reboot were all using some method or other to see through walls and clothing. Since we already live in the future, see through technology exists in myriad forms, not the least of which is airport full-body scanning. These scanners are so good at seeing past clothing that they might violate child porn laws in the United Kingdom. So now we’re in the position of trying to find ways to make see-through-stuff technology worse.

Enter the non-ionizing terahertz-frequency radiation. The terahertz range sits betwixt the infrared and the microwave bands of the electromagnetic spectrum. Pretty much everything on the planet emits it, and different objects emit different frequencies. Without any need for an emitter, a receiver could be designed to take pictures in the terahertz range. It wouldn’t have sharp lines, but terahertz radiation has a short range, and the emissions vary depending on the object. It would see people as a hazy silhouette. The radiation passes through wood, ceramics, cloth, and paper, but not metal or water.

In a short range situation —- like an airport security scanner —- a receiver could be installed to watch for the pattern of terahertz radiation. A person’s silhouette would show up fine, but a metal knife or handgun would appear as a black outline on the screen. There are already two companies with equipment like this ready to sell, and at least one CEO claiming the technology can be tuned to pick up radiation from drugs or other contraband a person might be carrying.

Not only would the new technology be safer, and avoid privacy concerns, it might make an airport security guard’s job a little better.

I’m in lovely La Jolla this evening, getting ready for my third annual contribution to SIO295/295L: Introduction to Marine Biodiversity and Conservation, Climate Change and Marine Ecosystems. It’s “Communications Week,” and I’m teaching a full day media training on tomorrow, to be followed up by Randy Olson teaching on film and, well, how not to be such a scientist.

The more of these sessions you do, the easier it is to get set in your ways–but I’m trying to avoid that. I’m changing things up.

In particular, I am going to start teaching about that Sagan clip I posted earlier–why was Sagan so effective? What message did he articulate, and why did it resonate enough that Cosmos was able to reach half a billion people around the world?

Would a similar science communication model work today? Or is it hopelessly dated?

Another thing I teach on is web-based science communication, and the blessings (and downsides) of blogs. In particular, I contrast science blogs with other forms of online communication that, I believe, have greater potential to reach non-scientific audiences–in particular, entertaining YouTube videos. Videos like this one (yes, that’s right Phil, as of today you made the curriculum!):

Why is Phil Plait good at what he does? Why is listening to him talk about black holes not a drag, not boring or wonky, but actually intriguing and more than a little amusing?

(For another example of Phil making black holes a blast–rather than a dark abyss–listen to our Point of Inquiry episode.)

At Scripps, and in these trainings in general, I teach the students the basics of how to design a message, how to deal with weirdo journalists, how to grapple with a changing media. But the higher level stuff–the stuff that makes a Phil Plait–isn’t something you can necessarily teach. It emerges from a combination of talent, insight, and creativity.

It’s…star stuff. (Thanks, Carl.)

My hope, though, is that by training larger numbers of scientists in the basics of communication, we’ll set some few on the path towards being real media entrepreneurs. It won’t be everyone. But there are more communication innovators out there than we’ve yet encountered–of that I’m very sure.

In the post below on the prolific nature of the Kennedy clan some commenters were curious as to the general socioeconomic slant of Irish Catholics. The GSS has a variable ETHNIC which asks which nation an individual’s ancestors came from. Combine that with RELIG, and you can figure out how Irish Catholics stack up nationally. While I was looking at Irish Catholics I thought I would look at whites from various nations. I decided to exclude Jews from the analysis because I think there’s a big difference between Polish Catholics and Polish Jews socioeconomically and we’d lose information aggregating. Further, I constrained the sample to non-Hispanic whites. To look at socioeconomic index I focused on the SEI variable. Here’s how SEI is calculated:

SEI scores were originally calculated by Otis Dudley Duncan based on NORC’s 1947 North-Hatt prestige study and the 1950 U.S. Census. Duncan regressed prestige scores for 45 occupational titles on education and income to produce weights that would predict prestige. This algorithm was then used to calculate SEI scores for all occupational categories employed in the 1950 Census classification of occupations. Similar procedures have been used to produce SEI scores based on later NORC prestige studies and censuses.

Here are some values for reference:

Jewish = 62
White non-Hispanic = 51
Hispanic = 43
Black = 42
Only High School Education = 43
Bachelor’s Degree = 63

I’ve crossed the ethnic groups with religion & region (RELIG & REGION):

I omitted cells where the N < 50. Additionally, “British” aggregates those of Scottish, Welsh, English, and “American” ancestry. Nordic combines those from all the Nordic countries. French includes Quebecois. I’ll let readers speculate, but I’m pretty sure that those with ancestors from Slavic countries of “No Religion” are disproportionately Jews.

Click here to view the embedded video.

Seems like a good project, I’m just not sure why NOAA isn’t doing it instead.  At least we aren’t waiting for somebody else, probably because all the other space agencies are doing, well, space stuff.

Source

These Australian pelicans (Pelecanus conspicillatus) were photographed at Perth Zoo. They provided a pleasant distraction from the fact that a bloomin’ great Icelandic volcano had just erupted and was about to ground me for a week…

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This week’s addition to the Science of Kissing Gallery was sent by Gyami Shrestha, who captured these seals near Cambria and San Simeon in California.

Submit your original photo or art for consideration in the growing collection of kisses–and kissing-like behaviors–across time, space, and species.

Meeting the press during a recent visit to Tokyo, NASA Astronaut Alan Poindexter — Commander of recent Discovery ISS resupply mission STS-131 — was asked if there had been sex in space. His reply was succinct and left no room for ambiguity (though this photo does look pretty chummy):

We are a group of professionals. We treat each other with respect and we have a great working relationship. Personal relationships are not … an issue. We don’t have them and we won’t.

Hang on a second. I’m not sure that the concepts of “sex in space” and “professional” are mutually exclusive. I’m sure that, given what we’ve learned about human physiology because of spaceflight, that there are any number of cardiologists, internists, endocrinologists, OB/GYNs, and a whole host of other health-care professionals and researchers who would love to have physiological data taken of a couple before, during, and after a union in a microgravity environment. These researchers would be the Masters and Johsons, Kinseys, and perhaps even the Shere Hites of their time.

For me, though, when I first read Poindexter’s denial about sex in space, the first thing I thought of was Gene Cernan.

Wait, that came out wrong. Better elaborate.

Gene Cernan (the last human to leave the lunar surface, fellow Purdue Boilermaker, and one of my personal heroes) did one of NASA’s first spacewalks on Gemini 9. Unlike the previous EVA (extra-vehicle activity) of Ed White in Gemini 4, Cernan did not have a hand-held thruster unit — the goal of the EVA was for Cernan to make his way to the back of the spacecraft and don a much larger maneuvering unit, like the MMU operated almost 20 years later. Cernan had a very difficult time maneuvering his body in the airless/microgravity environment of space, his visor fogged, his suit overheated, and he never made it to the back of the spacecraft. Michael Collins had similar difficulties aboard Gemini 10. Learning of the low-gravity tribulations of Cernan and Collins, Astronaut Buzz Aldrin designed tools, handholds, and techniques for his flight aboard Gemini 12, and moved comparatively effortlessly.

NOW you can probably see where this is going.

On Earth, when it comes to the act of making love, gravity is a great enabler — certainly when it comes to the, uh, harmonic oscillations one normally associates with various sexual acts. In microgravity, a whole host of Newton’s Laws of Motion come into play, and clearly one would need a bevy of straps, velcro, and fasteners — and that’s WELL before even coming close to the realm of the kinky.

The book “Sex in Space” by Laura Woodmansee describes several potential positions by which low-gravity sex could be performed, but after reviewing the book (strictly for scientific curiosity, mind you), it looks like many of those positions would leave Barbarella and Buck flailing about — not unlike Gene Cernan on Gemini 9. Space.com did a review on the book, covering some of the topics explored within, but they didn’t discuss the topic of potentially enabling positions. (LiveScience did, however, discuss this notion briefly; so did Robert A. Freitas, Jr.)

On the reverse side of that, under the right conditions the microgravity environment of near-Earth orbit might allow a return to intimacy for people who, because of injury or disease, can’t have sex on Earth. So after the upcoming explosion of private space flight, after we’ve established lunar colonies, you can almost see that the Sandals Resorts will get into the game with a new resort called “Moon Boots.”

Humor aside, and as “clinical” as this sounds, it might not be a bad idea to consider monitoring people having sex when there are protocols and experimental controls in place, instead of allowing people who simply want to join the “Hundred Mile High Club” experiment haphazardly.

We’d learn a lot about human physiology, and imagine the spinoffs!

Mitchell and Webb just keep on giving (one NSFW word):

I love how well he does Dawkins’ voice; it sounds very much like him.

Maybe we need to think about getting M&W to TAM London. Those guys are clearly One (well, Two) Of Us. If you’re not familiar with them, they do a comedy sketch show in the UK called "That Mitchell and Webb Look" and it’s brilliant. I have links to them below.

I think that in many cases, being funny gets the message across better even than being passionate. And a whole lot better than being a jerk. And you can even kinda be a jerk if you’re funny about it. Satire somehow seems to smooth the rough edges around a hard message…

One thing which has struck me about the Kennedy clan is that it seems inordinately fecund. The GSS tells me that in the 2000s white non-Hispanic liberals who are over the age of 45 have on average fewer than 2 children each. The ideal family size for the same segment is given as a little under 3. There isn’t any significant difference when constraining to the subset to those who are Roman Catholic.

So is my intuition about the Kennedy clan correct? There’s a helpful Wikipedia page which lists the descendants of Joseph P. Kennedy and Rose Fitzgerald Kennedy. Several of their children died too early to have any children of their own, or did not have children. Nevertheless, I count 69 great-grandchildren of Joseph P. Kennedy! Since his coefficient of relatedness to his great-grandchildren is 1/8, you get 8.63 in terms of his contribution to the current generation. But the real action is in two of Joseph P. Kennedy’s children, Eunice and Robert, whose own children seem to be quite prolific themselves. Below the fold is a list of the descendants. I’ve omitted some of those with no children in the first two generations.

Sit down, children, and let me tell you a story:  About 65.5 million years ago, whatever life forms there were present on this planet would have seen a terrible thing; they would have seen the end of the world.  A 10-15 km asteroid impacted the Earth in the Yucatan Peninsula with a force of over a billion times that of the nuclear blasts at Hiroshima and Nagasaki, combined.  The asteroid landed in a bed of gypsum, which would have released sulfur dioxide into the atmosphere.  There would have been a tremendous blast force, dust clouds, megatsunamis higher than any we’ve ever imagined, and an infrared pulse that would have lasted hours, killing by radiation.  Volcanic eruptions, global firestorms… well, I said it was the end of the world.  Anything specialized to an environment, that was picky about what it ate, or larger than a crocodile pretty much went extinct.  Anything that was small and could eat detritus (that would be non-living organic matter like fecal material and other organic trash) had a better chance.

Artist impression of Chicxulub Impact, NASA/JPL

Moving forward to the present time, in 1978 geophysicists working for the oil industry took a look at a strangely symmetrical crater at Chicxulub.  They read 1960s geological studies that theorized the crater was caused by an ancient impact.  The results of their exploration of the area were published in 1981, coincidentally the same year experimental physicist Luis Alvarez published his hypothesis that the K-T Extinction was caused by an impact.  Well, of course it was.  An international panel of 41 scientists have finally looked over all the evidence and have agreed that the extinction event was caused, at least in part, by the impact.  There were other global troubles at the time, which may or may not have caused some species to go extinct, but the event was definitely tipped over and put on the front burner by the impact.

Chixculub Crater, NASA/JPL

The Chicxulub crater itself is more than 180 km in diameter, which makes it one of the largest confirmed impact craters on Earth.  Material recovered from Chicxulub crater has been identified in part as shocked quartz, tektites, large deposits of iridium, andesite glass, and breccia.  You find these features in association with impacts.  I don’t think anyone really would argue that Chicxulub crater was caused by an impact.  Nothing else could have caused it.  It can’t be reproduced by natural Earth processes, and nothing causes shocked quartz except an impact.

Certainly, not every circular structure on the Earth is an impact crater (cough cough volcano), but this one definitely is from an impact; and when it formed, the world ended. I don’t know how many other times it’s happened here (definitely more than once), but I can tell you it will happen again.

For all you riddlers out there. As you all know by now Roger won the Bonus Riddle and we are starting a new cycle of riddles on Saturday.

I want to give you a heads up that we had an opportunity to give away another great prize.   A&E Entertainment has graciously given us a Blu-ray set of The Universe: Our Solar System.  What we are going to do is run a regular riddle, all the typical rules apply and this is open to everybody. First correct answer gets the loot. To be clear, the winner of this will still be eligible for the next bonus riddle too.

The disks won’t even be on sale until the 24th so here is a chance to be the first on your block to get them.

Here’s a link to the Amazon page, there’s another in the sidebar.

Product Description as seen on Amazon:

THE UNIVERSE: OUR SOLAR SYSTEM takes viewers on an exhilarating voyage through the cosmos. Witness the sun’s birth at the dawn of our solar system, and its death, billions of years in the future; explore the possibility of a human settlement on Mars; and learn about the devastating threats posed by the meteorites, comets, and asteroids that routinely collide with Earth.

From the farthest planets and stars in our solar system, back to the familiar face of our moon, HISTORY brings the mysteries of the heavens down to earth.

DISC 1: Secrets of the Sun / Mars: The Red Planet / The End of the Earth: Deep Space Threats To Our Planet / Jupiter: The Giant Planet / The Moon

DISC 2: Spaceship Earth / The Inner Planets: Mercury & Venus / Saturn: Lord of the Rings / Alien Galaxies / Life and Death of a Star

Good luck!  

One of the major issues which has loomed at the heart of biology since The Origin of Species is why species exist, as well as how species come about. Why isn’t there a perfect replicator which performs all the conversion of energy and matter into biomass on this planet? If there is a God the tree of life almost seems to be a testament to his riotous aesthetic sense, with numerous branches which lead to convergences, and a inordinate fascination with variants on the basic morph of beetles. From the outside the outcomes of evolutionary biology look a patent mess, a sprawling expanse of experiments and misfires.

A similar issue has vexed biologists in relation to sex. Why is it that the vast majority of complex organisms take upon themselves the costs of sex? The existence of a non-offspring bearing form within a species reduces the potential natural increase by a factor of two before the game has even begun. Not only that, but the existence of two sexes who must seek each other out expends crucial energy in a Malthusian world (selfing hermaphrodites obviously don’t have this problem, but for highly complex organisms they aren’t so common). Why bother? (I mean in an ultimate, not proximate, sense)

It seems likely that part of the answer to both these questions on the grande scale is that the perfect is the enemy of long term survival. Sexual reproduction confers upon a lineage a genetic variability which may reduce fitness by shifting populations away from the adaptive peak in the short term, but the fitness landscape itself is a constant bubbling flux, and perfectly engineered asexual lineages may all too often fall off the cliff of what was once their mountain top. The only inevitability seems to be that the times change. Similarly, the natural history of life on earth tells us that all greatness comes to an end, and extinction is the lot of life. The universe is an unpredictable place and the mighty invariably fall, as the branches of life’s tree are always pruned by the gardeners red in tooth and claw.

But it is one thing to describe reality in broad verbal brushes. How about a more rigorous empirical and theoretical understanding of how organisms and the genetic material through which they gain immortality play out in the universe? A new paper which uses plant models explores the costs and benefits of admixture between lineages, and how those two dynamics operate in a heterogeneous and homogeneous world. Population admixture, biological invasions and the balance between local adaptation and inbreeding depression:

When previously isolated populations meet and mix, the resulting admixed population can benefit from several genetic advantages, including increased genetic variation, the creation of novel genotypes and the masking of deleterious mutations. These admixture benefits are thought to play an important role in biological invasions. In contrast, populations in their native range often remain differentiated and frequently suffer from inbreeding depression owing to isolation. While the advantages of admixture are evident for introduced populations that experienced recent bottlenecks or that face novel selection pressures, it is less obvious why native range populations do not similarly benefit from admixture. Here we argue that a temporary loss of local adaptation in recent invaders fundamentally alters the fitness consequences of admixture. In native populations, selection against dilution of the locally adapted gene pool inhibits unconstrained admixture and reinforces population isolation, with some level of inbreeding depression as an expected consequence. We show that admixture is selected against despite significant inbreeding depression because the benefits of local adaptation are greater than the cost of inbreeding. In contrast, introduced populations that have not yet established a pattern of local adaptation can freely reap the benefits of admixture. There can be strong selection for admixture because it instantly lifts the inbreeding depression that had built up in isolated parental populations. Recent work in Silene suggests that reduced inbreeding depression associated with post-introduction admixture may contribute to enhanced fitness of invasive populations. We hypothesize that in locally adapted populations, the benefits of local adaptation are balanced against an inbreeding cost that could develop in part owing to the isolating effect of local adaptation itself. The inbreeding cost can be revealed in admixing populations during recent invasions.

First, plants are good models to explore evolutionary genetics. They’re not as constrained as say mammals, or the typical tetrapod, when it comes to barriers to gene flow between distinct taxa. Hybridization is common, and plants can also self-fertilize as well as cross-fertilize, allowing researchers to push the genetic pool in different directions (”selfing” obviously reduces the effective population and is an extreme form of inbreeding, so it’s a good way to purge genetic variation really quickly). In a perfect abstract world of evolution one might imagine Richard Dawkins’ vehicles and replicators as fluid entities which float along a turbid sea of evolutionary genetic parameters, drift, migration, mutation and selection. But reality is constrained to DNA substrate, which have their own parameters such as recombination, modulators such as epigenetics, and numerous ways to express variation through gene regulation. It’s complicated, and stripping the issues down to their pith is easier said that done.

But the broader dynamics here being examined is the generalist-specialist trade-off, which I think is relevant to the two issues I introduced earlier in this post. Specialists are optimized for their own position in the adaptive landscape, but have difficulties when it is perturbed. Generalists always less than maximum fitness in all landscapes, but higher average fitness across them because they can adapt to changes. Specialization is local adaptation of particular lineages, while in the generalist case you can have invasive species in novel environments. They’re obviously facing an adaptive landscape which is at some remove from what any of the introduced genotypes were “optimized” for, so hybridization produces something new for something new.

In the first figure of the paper you see F3 wild barley descended from two parental lineages, ME and AQ. The left panels show seed output as a function of heterozygosity, and the right panels as a function of ME genome content. Remember that in subsequent generations the descendants of hybrids will vary quite a big in genetics and phenotype as the original alleles re-segregate.

The takeaway is that in novel environments genetic variation seems to result in increased fitness. Why? One concept which one has to introduce is heterosis, whereby crosses between homogeneous lineages produce more fitness offspring. One reason this may be is that there is overdominance, where heterozygotes have greater fitness than the homogyzotes. This is the case with sickle-cell malaria disease. Another reason may be that in the original parental lineages there was a higher fraction of alleles which were deleterious in homozygote genotypes. In plain English, inbreeding resulted in genetic drift which cranked up the proportion of alleles implicated in recessively express negative phenotypes. The authors argue though that in the context local adaptation is strong enough to be a barrier against too much gene flow between the parental wild barely lineages, so the deleterious alleles are less likely to be masked. Only in a novel environment when that benefit was removed from the equation could the negative consequences of inbreeding come to the fore in the total calculus.

Figure 2 shows the results of experiments which examine the fitness of white campion, a European species which has been introduced in North America. In the left panel are crosses between native European lineages, with distance between parental lineages on the x-axis. In the right panel you have the same experiment, but with North American variants, which are products of introductions from various regions of Europe. The plants were grown in a “common garden,” to show how all the genotypes performed when environment was controlled.

As you can see moderate levels of hybridization entailed a benefit in the European variants, but not the North American variants. Hybridization between variants which were too distant did produce outbreeding depression in the European case, suggesting perhaps that disruption of co-adapted gene complexes resulted in a greater fitness cost than the masking of deleterious alleles due to inbreeding. One can make the inference from these data that the introduced white campion lineages are already hybridized, the barriers to crossing being removed by a disruption of the adaptive landscapes which each native lineages was optimized for.

Here are the authors from the discussion talking about invasions of exotic species:

Provided that multiple introductions from different source populations have occurred, the benefits of admixture become freely available to introduced populations that do not yet show a pattern of local adaptation. Because the benefits are potentially large, admixture may play an important role during early invasions. Native populations often show evidence of inbreeding depression…and one instant reward of admixture in the introduced range is the release of this genetic burden. Such heterosis effects can contribute significantly to the establishment and early success of invasive species…When tested together in a common garden experiment, invaders can show enhanced fitness-related traits compared with populations from their native range…If there is evidence of admixture, the effects of heterosis might be a default explanation for such observations, perhaps providing a null expectation against which other explanations (such as trait evolution) need to be tested.

What have plants to do with life as a whole? I assume much. Plants differ in the details, but compared to other complex multicellular organisms in regards to evolutionary genetics they’re quite liberated. By this, I mean that their modes of reproduction and promiscuity in hybridization make them more of an ideal “frictionless” test case of evolutionary biology and the power of the classical parameters. Perhaps given enough time natural selection would produce the ideal replicator to rule them all, to drive all others to extinction. But that day is not this day. And that day may never come because the universe is far too protean and erratic. Life is varied, on the phenotypic and genotypic level, and the exogenous processes of climate and geology continue to warp and reshape the adaptive landscape. And more subtly, but just as critically, life is always in an endless race with itself, as pathogens co-evolve with their hosts, and predators figure out how to outfox their prey. Life warps its own adaptive landscapes, and the innovation of one branch may lead to extinction of others as well as the proliferation of new branches.

More prosaically and anthropocentrically what does this say about us? Humans are an expansive species, and over the past 500 years different lineages have been hybridizing promiscuously. New genotypes have arisen in altered landscapes, and our pathogens are also riding the high tide of globalization onward and upward. We are ourselves a “natural experiment.”

Image Credit: Olivia Munn by Gage Skidmore

Link hat tip: Dienekes.

Citation: Verhoeven KJ, Macel M, Wolfe LM, & Biere A (2010). Population admixture, biological invasions and the balance between local adaptation and inbreeding depression. Proceedings. Biological sciences / The Royal Society PMID: 20685700