Asymmetrical features associated with anger

Don’t anger the asymmetric

After you read this piece, you will probably break out the measuring tape and try to figure out how prone to anger you are, because recent research indicates that anger can be measured in inches.

Using a clever ruse, researchers at Ohio State University found in 2004 that the more asymmetrical a person is in some physical features, the more likely that person is to become angry at rejection. In addition, the scientists found a role for testosterone and sex in these responses.

They duped 51 men and 49 women into thinking that they were attempting to raise money for a (false) charity. Participants had to make two phone calls in an effort to obtain a donation and expected to receive a reward if they were successful. Instead of the person on the other end of the phone being someone in the middle of his dinner, it was really a researcher, pretending to be a solicitee. At the first phone call, the solicitee pretended to be sympathetic, but politely said that he or she had no money to give. For the second phone call, the responder behaved rudely, saying the donation would be a waste of money. The first response was considered a low-provocation incident, and the second a high-provocation response.

Who hangs up phones any more?

When the unknowing study participants hung up the phone, the force of their hang-up was measured, as were their testosterone levels. Additionally, after the exercise, they had a choice of three letters to send to the people they had called; one letter was polite, one moderately pleasant, and the third accusatory and angry.

After collecting data on the ankles, foot width, ear height and width, palms, wrists, and fingers of the participants, the researchers looked for correlations between asymmetry of these characteristics and an angry response, as measured by the force of the telephone hang-up. They found that asymmetrical people became angrier and slammed the receiver more than symmetrical people. In addition, asymmetrical men hung up with more force under the low-provocation scenario, and asymmetrical women hung up with more force after confronting the rude responder.

Oh, testosterone and anger again?

Testosterone levels also played a role, with higher levels causing a more pronounced anger response, and again, the response showed a sex-bias. High-testosterone men were more likely to hang up forcefully after the low-provocation incident, and high-testosterone women after the high-provocation scenario.

What does it all mean? Are the asymmetric people sensitive to rejection, and thus, easily angered by it? Perhaps. But the researchers hypothesize that stress during embryonic development disrupts the embryo on several levels, from physical symmetry to neuronal connections. Scientists have long thought that shifts from symmetry during embryonic development—for example, the right-hand fingers developing a greater length than the left-hand fingers—occur because stressors send developmental signals awry. If the signals operate and are received correctly, both sides should develop the same way; but cigarette smoke, alcohol, and other stressors can disrupt these signals, and asymmetry—and quick anger—can be the result.

Testosterone and asymmetry

One intriguing finding of the study was that the asymmetry results reflected the testosterone levels of the participants. This outcome brings questions of the relationships among the hormonal parameters of development, their disruption, and later manifestations of these interactions.

If you’re wondering why men got so angry with the polite responder and women more so with the rude responder, here’s the researchers’ explanation: Men are quick to react with anger, but are not as comfortable as women with high-anxiety situations. So, when the tension amps up, men back off, but women may actually become more aggressive.

And those letters? More than a third of the participants wanted to send the rudest letter, regardless of their sex or levels of symmetry or testosterone. Perhaps they were merely foreshadowing the anger that now pervades American politics today.

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Has the ivory-billed woodpecker left the building?

Watercolor painting of ivory-billed woodpeckers from Audubon's Birds of America, 1826.

Imagine waking up one morning to real film footage of a duckbill dinosaur wandering around the Great Plains. Your reaction might be similar to that of birders around the world when Science magazine reported in 2005 that the ivory-billed woodpecker, thought for 60 years to have been extinct in the United States, still existed.

A forest bird of legend

The woodpecker entered birder and ecologist lore when its numbers declined in the early part of the 20th century. Its habitat was bottomland forest in the southeastern United States and Cuba, and its niche included drilling into mature trees. When people came along, logging away the woodpeckers’ homes, the bird appeared to vanish. By the 1920s, we thought it had disappeared forever, although in 1943, there was a single confirmed sighting of a lone female, flying over the stumps of an old-growth forest. She became a central figure in a PhD thesis in 1944. Then for 60 years, silence.

False calls

Well, not complete silence. There were many reports of sightings, but most were traced to another woodpecker species, the pileated woodpecker. The ivory-billed woodpecker differs distinctly from its pileated cousin in beak color, in having white patches on its back when perched, and in its size and the solid-black crest of the female. It has a three-foot wing span, which is huge for a woodpecker, and can grow as large as 20 inches long. It is a big, beautiful, and surprising bird, with a bright red crest on the males that must be startling to see among the cypress of a bottomland forest.

A mesmerizing obsession

Birders, possibly the most obsessive of any taxon fan club, had long wandered into the swampy bottomlands of Arkansas and Louisiana, trying to find ivory-billed woodpeckers. There was a confirmed sighting in Cuba in the ‘80s, and over the decades, people have claimed sightings or reported having heard the ivory-billed’s call. Professionals and amateurs alike have waded among snakes and fought off bugs, playing tapes of the call and listening for a response. At one point, searchers found a nest that had an ivory-billed look to it and trained a remote-sensing camera on it, but saw nothing.

And then in 1999, a kayaker thought that he had seen a pair of the birds. His report received serious attention from the government, local papers, and academic groups interested in the woodpecker both for its inherent beauty and for its status as a symbol of the price of our destructive tendencies. Soon, the old forests of the southeast were crawling with ornithologists, all hoping to catch a glimpse, take a picture, and emerge with definitive proof that a bird long thought to be extinct had survived.

The beat of the forest, revived?

Some people heard the drumming sounds the woodpecker is known to make. A handful of people who really knew their woodpeckers reported sightings. But it was a four-second video of the shy, reclusive bird that clinched it. The video is short and blurry, taken from a kayak in late April of 2004 on a camcorder. But even its poor quality couldn’t hide the distinctive markings and features of the ivory-billed woodpecker.

The confirmation set the world of ornithology astir, but it also reverberates among ecologists and environmentalists. The fact that at least one male ivory-billed woodpecker exists indicates that at least one breeding pair must have survived into the 1990s because the birds live 15 to 20 years at most. And it also might have meant a second chance for us and the woodpecker. Unfortunately, according to a recent report from Cornell researchers who have spent five years looking for more signs of the bird, “it’s unlikely that there are recoverable populations” of the bird where they’ve been searching.

Blind cave fish undergo eye exams

Mexican Blind Cavefish (Astyanax mexicanus) at Newport Aquarium

Blind cavefish have plenty to show us

It’s rare for an ancestral species to still be alive at the same time as its descendent species, but one example of this phenomenon is the blind cavefish. As its name implies, it is sightless and dwells in caves in northeastern Mexico. Aboveland, biologists can also find the ancestral species to these fish. The ancestral versions are all sighted, providing a perfect scenario for examining some of the genes involved in eye development and sight.

Warning: Bad pun ahead

Not blind to such opportunities, plenty of investigators have turned to Astyanax mexicanus and its ancestor as an animal model. These researchers focus on a field known as “evo devo,” or evolutionary developmental biology. With species such as A. mexicanus, biologists can examine genetic changes in developmental processes that lead to differences between organisms.

One group reported a few years ago that the rudimentary eye in the blind cavefish stopped developing because of overexpression of a pair of genes in the hedgehog family. The two genes, sonic hedgehog (shh) and tiggy winkle hedgehog (twhh) (evo devo folks have a little too much fun with gene names) influence many developmental processes, and in humans, appropriate shh expression results in the formation of two separate eyes, rather than a single, central eye. These researchers took the ancestral species of A. mexicanus and triggered production of extra shh and twhh during development on only one side of the head. On that side of the head, the fish exhibited arrested eye development as embryos, and the adults had no eye there.

Shh: Pleiotropic effects

Genes like shh have what we call “pleiotropic effects,” meaning that they influence several traits. As it happens, even as the blind cavefish lost sight, they gained in other adaptations to living in the dark, including reduced pigmentation, super-refined taste buds, and the ability to navigate using water pressure changes.

Many mutations + three evolutionary events = one outcome

Investigators also realized that for the 29 different populations of A. mexicanus dwelling caves in Mexico, each group might have a different suite of mutations that led to sightlessness. In other words, mutations in different genes in each population led to the same endpoint of blindness. Researchers knew for certain that sightlessness had evolved at least three times among these separated groups. The fish thus also provide an example of convergent evolution, when similar adaptations arise in separated populations or species because environmental pressures are the same.

The fish also offer a lesson in genetics. In studies of bacterial genetics, we learn about a process called complementation. It starts with mixing together two kinds of bacteria, one that has resistance to one chemical and another with resistance to a second chemical. Bacteria that end up with both genes will have resistance to both compounds, something easily tested by growing them on medium containing the two chemicals. This process is called complementation because the two bacterial gene sets complement one another when combined under these conditions.

Cavefish complementation experiments

Operating on a similar principle, a team of researchers crossed blind cavefish from different geographical areas. They thought that because different genes for sight had changed in different populations, the fish might also exhibit complementation. As predicted, in many cases, the genes of the father complemented the genes of the mother, resulting in a complete suite of genes appropriate for eye development in their offspring. The new fish, instead of experiencing truncated eye development, actually had eyes. The researchers had restored sight to the blind cavefish in a single generation. The effect was most pronounced between populations that were most distant from each other, reflecting the standard thinking that geographical separation often reflects genetic separation.

Fish eye exams

The same researchers also devised a clever test to discern whether or not a fish can see. They immobilized the fish and placed them inside a cylinder with flashing, shifting patterns of stripes in black and white. If the fish could see, their eyes would move with the patterns. Thanks to the blind cavefish, we have an excellent example of pleiotropy, convergent evolution, complementation, and natural selection principles, along with the first-ever test for determining whether or not a fish has sight.

Did division of labor defeat the Neanderthals?

According to some anthropologists, the classic depiction of Paleolithic man as a few strapping cavemen ganging up on a mammoth with their spears might need to be replaced with dioramas of women gathering seeds or a man scraping an animal carcass from the ground to take home for dinner. In addition, this division of labor between men and women may have given Homo sapiens the upper hand when it came to their competition with Neanderthals in the Upper Paleolithic, about 45,000 to 10,000 years ago.

You may be familiar with some of the usual reasons proposed for the extinction of the Neanderthals and the supremacy of H. sapiens in the competition for resources: The wily H. sapiens swarmed the Neanderthals, defeating them in war with superior weaponry or a greater ability to resist disease or defy climate change. Some experts have proposed that a combination of these climatological and cultural factors may have contributed to the Neanderthal’s loss. But until now, no one had focused on differences in division of labor as giving H. sapiens the advantage.

The crushing hand of the Neanderthal woman

Evidence shows that Neanderthal men and women may have shared similar robust builds. In addition to bone finds that suggest as much, a researcher who focuses on hand mechanics has found that the Neanderthal female hand could exert as much force as that of a male. In addition, Neanderthal home sites rarely include artifacts such as tools for grinding seeds or trapping small animals, or even evidence of clothing production, such as needles. Thus, it seems that the Neanderthals may have, as a group—men, women, and children—spent their time focusing on one thing: big game.

Hunting a large animal that has defense ranging from tooth to antler to hoof to claw is a dangerous business, more so when your only weapon is a pointed stone attached to the end of a stick. Neanderthals got a big payoff when their spears worked, however, in the form of calorie- and protein-rich meat for the group. Evidence suggests that the whole group participated in this dangerous task—the bones of females as well as males bear the signs of many fractures, possibly the result of this dangerous lifestyle. Women and children may have been responsible for driving game or forging escape routes should the angered and frightened animal have turned on the group.

The pitfalls of group big-game hunting

This focus on a single kind of food source can have predictable consequences. In times of scarcity, the Neanderthals lacked other options. If they had no training or skills to obtain other food sources, then scarce big game translated into scarce Neanderthals. Homo sapiens, on the other hand, may have developed a division of labor between men and women before emerging from Africa 150,000 years after the Neanderthals, equipped with women who knew how to make protective clothing, trap small animals, and collect and prepare seeds and vegetation, and men with advanced weaponry who could efficiently hunt game. In addition, these people may have relied on scavenging as well as hunting to boost their food supply.

Division of labor gave H. sapiens the upper (non-crushing) hand?

The division of labor, which in some societies was reversed or not allocated in the same way between men and women, allowed Homo sapiens to adjust when food was scarce and boom when food was plentiful, or so some researchers now argue. These archaic humans could use their clothes-making skills to handle climate change and their efficient allocation of time resources to bring in food simultaneously from different sources, even when times were tough. Their booming population may have given them the numbers they needed to outcompete the Neanderthals.

…Or maybe not

Some researchers disagree with this hypothesis, suggesting that evidence of a division of labor dates back one or two million years, and there have been some predictable references in the news media to men’s and women’s roles today. One of the authors of the “division of labor” study explicitly cautions that what was beneficial 40,000 years ago isn’t necessarily a guide to what is beneficial today. Traits that provide a competitive edge are after all entirely reliant on context: What’s good in one environment may not necessarily be that helpful in a different set of circumstances.

Excerpt from The Complete Idiot’s Guide to College Biology: Mendel

Gregor Mendel achieved success in his religious order in his lifetime and lasting scientific fame after his death.

Mendel and the pea plants

Gregor Mendel used tens of thousands of pea plants to make several accurate observations about inheritance decades before scientists demonstrated any of it with modern techniques. With his plants in an abbey garden, he established two laws of inheritance that reflect directly the events of meiosis, again a discovery that predated confirmation using modern techniques. His brilliance lay in his method and his math.

Math also underlies our calculations of inheritance today, determining probabilities about who will inherit which genes. The associations between genes and the characters they give us are more complex than what Mendel derived from his pea plants. They extend beyond the concept of a single gene to multiple genes and even inheritance linked to entire chromosomes or to mitochondrial DNA.

Devoutly statistical

People may have a hard time wrapping their minds around the real brilliance of Gregor Mendel, the plant-crossing monk. Some students likely walk away from their studies of Mendel and his pea plants with the impression that he got lucky with those plants. But Mendel was not only lucky. He was smart, he knew his plants, and he was a true scientist who understand how to translate the biological underpinnings of his statistical results.

He also was a monk who lived in the St. Thomas Monastery for most of his adult life, where he worked as a teacher and cultivator of plants. It was the peas that would eventually lead to his fame, although Mendel died before the fame that was his due finally came his way.

Mendel’s choice:  observation, not luck

Mendel came to science through a natural inclination and a great deal of training. He always had an interest in science, studying physics and chemistry at a university, and teaching science at the school associated with the monastery. At the abbey, he followed his scientific passions with his studies of variation in pea plants.

Mendel didn’t choose these plants by accident. He knew from experience that they had critical features that made them an excellent choice for his study organism. He could self cross a plant, meaning that he could use a plant’s pollen to fertilize the same plant’s ovule. The pea plants had a set of binary traits, meaning that they were either green or yellow or had either wrinkled or smooth peas, nothing in between, no “blending.” And they had short generation times, meaning that they matured fast and he’d get his results quickly.

29,000 plants

Also, Mendel was a mathematician who could interpret his statistical data. Mendel generated a lot of data, ultimately working with about 29,000 plants to achieve his grand opus on genetics. This opus, entitled “Experiments on Plant Hybridization,” generated almost no attention from other scientists. It remained rarely cited and of little interest for decades until resurfacing in the twentieth century, when scientists began to appreciate its genius.

Why is it a work of genius? Because with nothing in the way of molecular biology tools, with no information about genes or heredity, Mendel used 29,000 pea plants to figure out exactly how parents pass on their traits to offspring. He did it through insight into the organism he chose and his training as a mathematician and scientist. But he also did it because, as is the case with so many of the greatest scientists, he had a single-minded tenacity that led him to spend years studying in headache-inducing detail the minutiae of reproduction in 29,000 plants.

Posthumous scientific fame

Now, Mendel’s work is considered so important that we’ve named an entire portion of the study of genetics after him. We call it Mendelian genetics, the genetics of heredity from parent to offspring. Mendel is now known as the father of genetics.

In spite of scientific fame coming to him only posthumously, Mendel did have a different sort of success in his lifetime. When he died, he was Abbot of his monastery, having dedicated his life to his Augustinian order, his abbey, and, through his pea plants, to science.

Bisphenol A: multisystem effects

These bottles were produced without BPA in response to concerns about the chemical. Photo via Creative Commons, attributed to Alicia Vorhees, thesoftlanding

Are endocrine disruptors stealing our future?

Endocrine-disrupting compounds are chemicals in the environment—usually compounds that we have introduced—that can alter normal hormone signaling processes. Often, exposure to these compounds has little immediate effect in adult animals, but it can have big effects on organisms during sensitive developmental periods, like embryogenesis. During embryonic development in vertebrates, steroid hormones govern many processes, and the fetal hormone environment is usually carefully calibrated to ensure that these processes go forward normally.

Tiny amounts, big changes

But many compounds disrupt these processes, knocking them off track and resulting in development that is unusual or abnormal. For example, male alligators exposed in the egg to these compounds—which often persist in fatty tissues or yolk—emerge with serious penile abnormalities that can affect their ability to reproduce. The banned pesticide DDT is probably one of the best-known of these compounds, and exposure to it or its metabolites has been shown to disrupt hormone signaling to the point of altering sex development completely.

When we think of hormones, we often think of puberty, the time when hormones seem to govern our every move. When we think of estrogen, we probably think “female” because estrogen has historically been considered the “female” hormone. What you might not know is that estrogen, which is made in the ovaries, is also made in our brains during embryonic development. In mammals, appropriate male development appears to require neural estrogen synthesis. When estrogen synthesis in embryonic mammals is blocked, the males that develop do not exhibit typical male behaviors when they reach reproductive maturity.

Bisphenol A: ubiquitous chemical

Among the compounds that have been identified as endocrine disruptors is bisphenol A (BPA). In the United States, we produce about 2 billion pounds of BPA a year. Previous studies have demonstrated that BPA can disrupt thyroid signaling to the point of affecting the thyroid’s role in appropriate brain development. In addition, BPA has been linked to feminization of reptiles. Some scientists were aware of BPA’s hormone-activity potential as far back as the early twentieth century.

But because no one took that knowledge or its potential seriously—the field of endocrine disruptors is relatively young—BPA has found its way into almost every aspect of our lives. It is in the dental sealants we put on our teeth to keep the cavities at bay. It is in the lining that coats the insides of food cans to keep the metal from rusting. It is in the hard plastic that we use for baby bottles and teething rings. And it can leach from these products into the food that we eat. BPA is found at high levels in some pregnant women, and it appears to accumulate in higher concentrations around the umbilical cord and in the fetal amniotic fluid.

BPA and effects on the developing brain

Work from Yale and from researchers in Japan also points to some potentially serious effects on the brain. Part of the role of estrogen in brain development is facilitating synaptic connections in a crucial brain area called the hippocampus. The hippocampus is the center where neurons organize that will later be activated to produce sex-appropriate activity in vertebrates. It is also the area of the brain involved in the formation and retention of memory.

The researchers found that small doses of BPA—doses that fall within EPA-approved levels for exposure—can inhibit hippocampal synaptic formation in rats, counteracting the effect of estrogen. That BPA is an estrogen inhibitor could be serious for our brains if the results translate into human effects. As we age and our endogenous estrogen levels decrease, for example, the hippocampus suffers and our memory does, too. If BPA sets this process in motion even earlier, hippocampal—and thus, memory—decline may occur even earlier.

Rodents, monkeys, and people–oh, my

A recent report in Environmental Health Perspectives concludes that rodents, rhesus monkeys, and people all exhibit similar pharmacokinetics with BPA and that exposures may be far greater than previously calculated. Other recent studies suggest effects on sugar metabolism related to diabetes, an association with polycystic ovarian syndrome in rats, and a relationship to the development of asthma in a mouse model.

How the genetic code became degenerate

Our genetic code consists of 64 different combinations of four RNA nucleotides—adenine, guanine, cytosine, and uracil. These four molecules can be arranged in groups of three in 64 different ways; the mathematical representation of this relationship is 4 x 4 x 4 to illustrate the number of possible combinations.

Shorthand for the language of proteins

This code is cellular shorthand for the language of proteins. A group of three nucleotides—called a codon—is a code word for an amino acid. A protein is, at its simplest level, a string of amino acids, which are its building blocks. So a string of codons provides the language that the cell can “read” to build a protein. When the code is copied from the DNA, the process is called transcription, and the resulting string of nucleotides is messenger RNA. This messenger takes the code from the nucleus to the cytoplasm in eukaryotes, where it is decoded in a process called translation. During translation, the code is “read,” and amino acids assembled in the sequence the code indicates.

The puzzling degeneracy of genetics

So given that there are 64 possible triplet combinations for these codons, you might think that there are 64 amino acids, one per codon. But that’s not the case. Instead, our code is “degenerate;” in some cases, more than one triplet of nucleotides provides a code word for an amino acid. Thus, these redundant codons are all synonyms for the same protein building block. For example, six different codons indicate the amino acid leucine: UUA, UUG, CUA, CUG, CUC, and CUU. When any one of these codons turns up in the message, the cellular protein-building machinery inserts a leucine into the growing amino acid chain.

This degeneracy of the genetic code has puzzled biologists since the code was cracked. Why would Nature produce redundancies like this? One suggestion is that Nature did not use a triplet code originally, but a doublet code. Francis Crick, of double-helix fame, posited that a two-letter code probably preceded the three-letter code. But he did not devise a theory to explain how Nature made the universal shift from two to three letters.

A two-letter code?

There are some intriguing bits of evidence for a two-letter code. One of the players in translation is transfer RNA (tRNA), a special sequence of nucleotides that carries triplet codes complementary to those in the messenger RNA. In addition to this complementary triplet, called an anticodon, each tRNA also carries a single amino acid that matches the codon it complements. Thus, when a codon for leucine—UUA for example—is “read” during translation, a tRNA with the anticodon AAU will donate the leucine it carries to the growing amino acid chain.

Aminoacyl tRNA synthetases are enzymes that link an amino acid with the appropriate tRNA anticodon.  Each type of tRNA has its specific synthetase, and some of these synthetases use only the first two nucleotide bases of the anticodon to decide which amino acid to attach. If you look at the code words for leucine, for example, you’ll see that all four begin with “CU.” The only difference among these four is the third position in the codon—A, U, G, or C. Thus, these synthetases need to rely only on the doublets to be correct.

Math and doublets

Scientists at Harvard believe that they have solved the evolutionary mystery of how the triplet form arose from the doublet. They suggest that the doublet code was actually read in groups of three doublets, but with only the first two “prefix” or last two “suffix” pairs actually being read. Using mathematical modeling, these researchers have shown that all but two amino acids can be coded for using two, four, or six doublet codons.

Too hot in the early Earth kitchen for some

The two exceptions are glutamine and asparagine, which at high temperatures break down into the amino acids glutamic acid and aspartic acid. The inability of glutamine and asparagine to retain structure in hot environments suggests that the in the early days of life on Earth when doublet codes were in use, the primordial soup must have been too hot for stable synthesis of heat-intolerant, triplet-coded amino acids like glutamine and asparagine.

The song of the iceberg

Before the advent of radar and sonar navigation, sailors used to traverse iceberg-littered waters by listening for sounds to indicate how close or how far away an iceberg was. Since the wreck of the Titanic, people have moved beyond the basic human ear to track icebergs, but if we had whale ears, sound might still be sufficient.

That’s because some icebergs can sing. It’s not exactly an aria—more like a cacophonous symphony warm-up—but it still sounds like a song. Unfortunately, it’s not a song we can hear unaided with our unworthy human ears, which cannot detect the very low frequency—about 0.5 Hz—the icebergs emit. It is possible that whales might be able to pick up the sounds since they can detect very low frequencies.

A brief primer on sound

Sound travels in waves, and those waves have frequency—the speed at which they arrive—and amplitude—the size of the wave. Sound is detected when the waves vibrate something; in the case of our own ears, sound waves hit and vibrate the membranes of our inner ears, triggering hair cells that send nervous signals to our brains, where we process the sound. High-frequency waves produce high-pitched sounds, and low-frequency waves produce bass.

Because we can’t hear the low frequencies the singing icebergs emit, their song went undetected until a fluke discovery by a team of earthquake researchers. The team had been using seismic equipment to monitor earthquakes in the Antarctic region. The seismograph produces on paper the frequency and amplitude of vibrations of the earth as movement occurs. An earthquake pattern usually looks like a flurry of large-amplitude events that tapers off and ceases. But the researchers discovered one day a pattern that looked more like a comb—vibrations occurring at regular frequencies and being sustained for a fairly long period of time.

Earthquakes lead to iceberg song

Mystified, they tried to locate the source of the recordings, which seemed to ramble all along the continent’s edge. But it wasn’t until July 2000 that they had a breakthrough. Two small earthquakes triggered a signal that lasted for 16 hours. This event gave them the opportunity to use satellite tracking to pinpoint where the signals were being generated. The epicenter of the quakes turned out to be an iceberg over 1200 feet high that had lodged against an underwater peninsula jutting from the continent. The iceberg was slowly edging its way along the shelf, apparently singing as it went.

The researchers surmised that when the iceberg became lodged, water pressure built up within the crevasses and tunnels that crisscross these floating mountains of ice. The pressure, they speculate, caused water to rush through these deep gulleys and holes, vibrating the walls and producing the “song” of the iceberg. The scientists made a recording of the seismic noise and sped it up, increasing the frequency to a level that human ears could detect. The recording sounds like something between a screech and the playing of a lot of untuned violins. But eventually, it merges into a smooth sound that evokes many stringed instruments playing the same note simultaneously. (Click on the video above to hear.)

From icebergs to volcanoes

The comb-like signal that the iceberg’s vibrations produced is very like what volcanoes produce when they tremble and vibrate. Now that researchers have hypothesized a mechanism to explain the vibrations, they hope to try to apply the concept to volcano models, which are difficult to study because of the heat factor. An iceberg is not the only thing on Earth that consists of a solid substance riddled with tunnels and crevices through which liquid flows, and may serve as a good volcano model.

Going to Hawaii? Watch out for the flesh-eating caterpillars

Flesh-eating caterpillars lurk in Hawaii’s rainforests

Islands can produce some of the strangest evolutionary novelties on the planet. Island-living elephants shrink to tiny sizes, while tortoises grow gigantic. The fate of species on islands is its own specialized study because the only way species can arrive on an island is over the water. Scientists, in the study of island biogeography, focus on how plants, animals, and microbiota end up on the islands where they occur.

What happens after they arrive is apparently anybody’s guess. Islands are unusual because they can lack the stiff competition of mainland ecosystems. Common factors in our daily lives, like ants, can be completely lacking. Because so many pieces of an ecological puzzle are missing on an island, niches remain open for the organisms that do arrive and get a foothold. Animals and plants end up doing things on islands that their kindred are not known to do anywhere else in the world. A recently discovered example is a caterpillar that has broken all the rules of caterpillardom. It eats meat. It hunts its prey. It uses its silk as a weapon. It deliberately camouflages itself with non-caterpillar components. And it’s a brutal killer.

Like a wolf that dives for clams

This particular capterpillar and its four just-discovered relatives reside on one of the most isolated island chains in the world, the Hawaiian archipelago. These islands are well known for evolutionary novelties, and these new species of the genus Hyposmocoma are no different. Well, actually, they’re very different. One scientist has said that discovering the behavior of these larval moths is like discovering a wolf species that dives for clams.

This caterpillar, a tiny, brutal, sneaky killer, creeps up on its prey, an unsuspecting snail resting on a leaf in the Hawaiian rainforest. The caterpillar itself is bound in silk, and it proceeds to spend almost a half hour anchoring the hapless snail to the leaf with more silk. The silk, made of gelatinous proteins, pins the snail by its shell as tightly as a spider wraps its threads around prey.

Once the caterpillar has immobilized its target, preventing the snail from escaping through a fall off of the leaf, the nascent moth emerges from its own silk casing. The snail retreats into its shell, and the caterpillar follows, beginning to feed on the trapped snail, starting with the head. It literally eats the snail alive.

This behavior is extraordinarily unusual for a caterpillar, the juvenile form of moths and butterflies. The vast majority of caterpillar species are vegetarian; of the 150,000 known species, only 200 have been identified as flesh eaters and predators. These few do not use their silks to trap their food, and they don’t eat snails, which are mollusks, targeting instead soft-bodied insects.

Caterpillar divers and adaptive radiation

But the genus Hyposmocoma is known for its diversity. Some of its members dive underwater for food. The interesting thing about the snail-eating caterpillars is that they seem to have radiated through almost all of the Hawaiian islands. The first species was identified on Maui, but since its discovery, researchers have found species on most of the other islands. Evolutionary biologists are intrigued by the many novel aspects of this caterpillar’s life history because it is so unusual for this many unique factors—novel food source, novel hunting technique, novel eating technique—to have evolved in the same species.

Wearing the spoils of capture as camouflage

One other unique thing about this caterpillar’s approach to dinner is its use of decoration. Once the mollusk-eating caterpillar has spent the day dining on escargot, it will attach the snail’s empty shell to its silken casing, along with bits of lichen and other materials, in an apparent attempt to camouflage itself.

Ancient Peruvian beer breweries

Rich Peruvian women brewed beer

When it comes to drunken women, the Peruvians have always been different. In many societies, women are not supposed to drink at all. They certainly aren’t supposed to get knee-walking, rip-roaring drunk, matching shot for shot with a man. It’s generally considered unladylike, and these days, studies keep coming out indicating that overimbibing may have more adverse effects on women’s health than it does on men’s.

But the Peruvians of today, especially those living in the Andes, indulge in equal-opportunity carousing. It appears that they simply are following a tradition that may be more than 1000 years old.

What drove agriculture? Beer or bread, naturally

A few years ago, archaeologists discovered large broken vats on top of a 8000-foot-high mesa, Cerro Baul, in the Peruvian Andes. Among the vats were the remnants of smaller vessels and some shawl pins that belonged to noblewomen of the Wari people, a pre-Incan civilization that suddenly disappeared about 1000 years ago. From about 600 AD to 1000 AD, however, the civilization flourished around Cerro Baul. Nobles lived on the mountaintop, and farmers and middle-class artisans and technicians lived and worked in the valleys below.

The researchers felt that they must have stumbled across one of the world’s ancient breweries. Breweries attract anthropologists and historians because beer competes with bread as the driving force behind the development of agriculture. Every civilization appears to have brewed, usually using grains like wheat and barley. Some of the oldest suspected breweries date back as far as 3000 BC in Egypt, and suspected breweries have also been discovered in what is now Iraq.

But the equivocal “suspected” is what makes the Peruvian find so delicious. Ancient breweries defy clear identification because the beer was brewed from the same grains used to make bread; thus, it is difficult to distinguish the cereal-based residue on pot fragments as the result of brewing vs. baking. What the brewery-hunters of the world needed was a civilization that used some unusual ingredient in its beer, something that they didn’t also use in their bread. And they found it in the Wari people of ancient Peru.

Corn fermented, pepper-flavored beer

Even today, native Peruvian beer stands out among the world’s brews. It is fermented from corn and flavored with berries from the pepper tree. No other beer in the world has this combination, and the Peruvians apparently do not use the pepper tree to make bread. This concoction, called “chicha” today, is apparently very like what the Wari people brewed high on their mesa 1000 years ago.

The researchers latched onto pepper tree residues as the ingredient that would allow them to definitively identify an ancient brewery. The pepper berries contain a compound called oxalic acid that can adhere to ceramic pottery for centuries. Using techniques like liquid chromatography, they were able to confirm that this compound was indeed present in the large vats on Cerro Baul.

Wild, ancient Peruvian bacchanal

They had suspected as much. The vats themselves were huge and obviously designed to hold liquid. The surprise was that the brewery and the vats appeared to have been destroyed in a single night of carousing just before the Wari abandoned their mountaintop. Researchers surmise that the nobles of the town engaged in ritual drinking and drunkenness—the big guns got the larger Wari beer steins—and then, when the ceremony ended, they destroyed their ceramic vats and set the place on fire. After the building had burned to the ground, the nobles placed jewelry on top of the remains, possibly to identify it as a sacred place.

Interestingly, among the destruction, the archaeologists found the noblewomen’s shawl pins. They surmise that the women may have brewed the beer; in later Incan civilizations, upper-class women brewed beer, and only upper-class people drank chicha with the pepper-tree flavor added.

Of course, you have to taste test it

When it was active, the brewery may have produced hundreds of gallons of beer a week. In an effort to experience the flavor, some archaeologists recreated the ancient concoction and report that it is not quite as dark as a modern-day stout, and has sweet, peppery flavor with a bitter finish.

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