James Scott Berdahl

Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body


A review of Your Inner Fish: A Journey into the 3.5-Billion-Year History of the Human Body by Neil Shubin
256 pages.

We can walk because we have teeth. More than 500 million years ago, in some primordial sea, a soft-bodied, worm-like creature developed hard, pointed growths inside its mouth. These growths were a mutation, a freak accident in the replication of its genetic code, but they proved quite useful when it came to eating other soft-bodied, worm-like creatures. The code for these hard growths was passed on, and over eons, it was muddled even more. Eventually mutants arose with hard growths that covered their entire heads, and these new features also came in handy—this time to fend off all the soft-bodied, worm-like creatures swimming about with big teeth. After this, the genetic code for the hard structures continued to morph, giving rise over the ages to backbones, ribs, fins, and then, some 375 million years ago, legs.

Your Inner Fish comes in the aftermath of Neil Shubin’s historic co-discovery of Tiktaalik, a “found link” between prehistoric fish and the world’s first amphibians. Shubin, a paleontologist and professor of anatomy at the University of Chicago, found the fossil in 2004, after years of scouring Devonian aged sedimentary rocks in the high arctic of Ellesmere Island, right where a chronological sandwiching of other fossils said it should be. In this quick, enlightening, and entertaining read, Shubin recounts the motivation for hunting for Tiktaalik and the details of its discovery, and then he uses this “fish with wrists” as a jumping off point for a discussion—conversational in tone but compelling in content—on the origins and implications of many of our distinguishing features. Full Review »

Snakes in a Plane: Polarization and 3-D Cinema


Perhaps you’ve seen James Cameron’s recent blockbuster Space Pocahontas, er Avatar. You sat in a theatre packed with makeshift Buddy Hollies as nude extraterrestrials darted among trees. Floating islands and pterodactyls popped out of the screen in glorious 3D, and then our decendents came to pillage the land with fire and obtain its unobtainium (they should have known better). It was fun, wasn’t it?

For all the fanfare though, three-dimensional cinema is nothing new. The idea of showing each eye a slightly different image to generate the illusion of depth has been around for well over a century, and almost every moviegoer has donned a pair of migraine-inducing red and blue shades at some point. But the technology behind this most recent wave of 3D enthusiasm is new, and I was surprised to learn how it worked. The secret is a novel use of polarization.

Light, such as that emitted by a film’s projector, travels as a wave. As it moves along a straight path, it shakes an electric field back and forth, a bit like a tiny snake slithering its way through space. But unlike actual snakes, which must slither along the ground’s surface, the light wave can shake its electric field up and down, side to side, or at any angle. Most sources emit its light waves randomly, so that the electric fields end up shaking in every direction. This is non-polarized light.

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The Elusive Wasabi


There’s an imposter at the sushi bar. I’m not talking about the artificial crab—the artificial crab is genuine artificial crab, a red-painted scrap of pollock. And I don’t mean the Americanized variants of Japanese cuisine either, the California rolls or the sake bombs. They don’t claim to be anything they’re not.

No, the imposter takes the form of a dull green mound that waits alongside your ginger before erupting into your sinuses and sending tears streaming out from behind your eyes. You know him as wasabi. His real name is horseradish.

The majority of sushi bars do not serve real wasabi. This surprised me. Rummaging through my roommate’s arsenal of Japanese culinary supplies, I located a bag of the stuff and read off its ingredients.

The explosive green paste making inroads on the North American palette is little more than a combination of dried horseradish, mustard, and blue and yellow coloring. Occasionally, a brand will throw in some concentration of dried wasabi power, but even then it’s the horseradish that does the talking.

So why aren’t we eating the real thing?

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New Report Offers Gloomy Forecast for Carbon Dioxide Reductions


Apart from global economic collapse, little can stabilize climbing carbon dioxide emissions, says a new paper from atmospheric scientist Timothy Garrett.

Garrett applied basic physical rules to civilization as a whole and found that to stop the ongoing rise in CO2 emissions, we’d have to create one nuclear power plant’s worth of new green energy output every day, in addition to meeting our current demands.

In analyzing worldwide economic and energy data ranging from 1970 to 2005, Garrett saw a fixed relationship between the energy consumed by society and the production value of the global economy. This relationship worked out to be 9.7 milliwatts per inflation-adjusted U.S. dollar, meaning that for every dollar’s worth of economic output, society uses 9.7 milliwatts of power. “This is really the core result from which everything else follows,” says Garrett, who is an associate professor at the University of Utah.

The relationship he found held up through the surges, bubbles, and recessions seen in the economy over the past three-and-a-half decades. It also held over earlier data points, which were sparse and went as far back as 2,000 years.

Garrett’s result points to a feedback loop in which energy consumption leads to economic growth, which in turn leads to increased energy consumption and thus more growth.

He calculated a 2.1 percent rise in the global economy’s rate of return for 2005, corresponding to a 300 gigawatt rise in the world’s power needs for that year. These additional gig Full Article »

Jerome Hunsaker’s Dark Shadow


He was a champion of aeronautics. He taught the first course on the subject at MIT in 1914 and built America’s first modern wind tunnel there two years later. He was responsible for the development of U.S. naval aviation during World War I, and in 1919 his NC-4 became the first aircraft to fly across the Atlantic. He designed an early communications system for airplanes, a landing system for aircraft carriers, and served as the chairman for the National Advisory Committee for Aeronautics, the precursor to NASA. As a pioneer of American aviation, it seemed Jerome C. Hunsaker could do no wrong.

In his eyes, however, a dark shadow hung on his career. More than a simple regret, it spanned two decades of his efforts and research. This shadow was cast by the American dirigible, by the years he spent championing its development and driving its evolution, by the resources that had been wasted and the lives that had been lost in a series of disastrous failures.

He spoke of his frustration in a 1960 interview, lamenting the men that had died in his dirigibles. “They thought I knew what was what, and they took my word for it,” he said. “We should have anticipated, as good engineers, [that] the rigid airship would become obsolete about the time it was established.”

But at the outbreak of World War I, a younger Hunsaker burgeoned with cautious optimism at the potential of airships, which could fly at night, in fog, at high altitudes, and over long distances. “Dirigibles may not revolutionize naval warfare,” he wrote in a 1914 letter to the Technology Review, “but may play an important, if auxiliary, part in it.” Full Article »

New Protein Found Promising in Prevention of HIV Infection


A new protein aimed at preventing HIV infection in humans has proven itself in initial lab tests. The protein is a mash-up of two previously existing proteins that occur naturally in humans.

While existing HIV therapies target the virus after it has started to make itself a part of its host’s cells, the new protein acts on the virus at a much earlier stage, rendering the virus ineffective before it can do any harm.

“It’s a new approach,” says Martha Neagu, the lead author of the paper announcing the findings, “and it’s a very effective approach.”

The idea to create this protein came from a previous study of South American owl monkeys, in which a similar compound protein was identified as the mechanism behind the monkey’s immunity to HIV. Human cells don’t produce this compound protein, but they do produce its two constituents.

“This is a modular protein, and we have the tools in our human gene arsenal to make an equivalent,” said Neagu. She and her team at Columbia University constructed their own version of the monkey’s HIV inhibitor by splicing together the genetic codes of the components that are already found in humans, creating eleven potential blueprints for the compound protein. Full Article »

Nice Guys Finish First


Researchers have taken a healthy stride towards understanding the evolutionary role of the nice guy.

A recent study of water striders—insects found skimming the surfaces of ponds and streams around the world—showed that while aggressive males enjoy greater reproductive success as individuals, more gentlemanly striders gain an unexpected advantage in the bigger picture.

The problem for aggressive males is that female water striders quickly tire of their harassment and skate away to regions inhabited by more laid back individuals. “The key result is that this really affects the success of the males,” says Stuart Wigby, an evolutionary biologist at Oxford. With more females around, the laid back males have a greater shot at reproducing.

“Nice guys don’t always finish last,” says Omar Eldakar, the study’s principle investigator.

Prior to this research, it was unclear how non-aggressive males fit into evolutionary competition. But Eldakar recognized a link between this problem and “the tragedy of the commons,” a trend that normally applies to overexploitation of natural resources. “If there are individuals that are sharing a common resource, then selection is going to favor a short term exploitative strategy,” he explains. “Eventually the resource is destroyed.” Full Article »

Variety of Dog Coats Governed by Just Three Genes


With their smiling eyes and wagging tails, dogs often make life easier for us. As it turns out, their DNA recently had a similar effect for geneticists. Most of the complex array of coats that dogs wear—from the halo of softness engulfing the Pomeranian and the wiry bristles of a Scottish Terrier to the curls of a spaniel and the sleek jacket of the lab—can be reduced to the influence of just three genes.

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Jumping Genes


Genes can leap between plants and fungi, say a group of British researchers who recently discovered nine such genes that had crossed from one biological kingdom to the other.

This phenomenon, known as horizontal gene transfer, had previously been identified within taxonomic kingdoms. It’s common among bacteria, and genes have even been observed to jump ship from one plant species to another, likely due to sexual accidents associated with their free-drifting pollen.

In fungi, researchers have found that horizontal gene transfer may be responsible for the toxicity of wheat fungus, as well as the ever-popular alcohol-producing metabolisms of wine yeast. The pervasiveness of the process has caused geneticists and evolutionary biologists to recognize its importance as a factor in the evolution of Earth’s biosphere.
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