Nudibranchs David Doubilet
A nudibranch is a member of Nudibranchia, a group of soft-bodied, marine gastropod mollusks which shed their shell after their larval stage. They are noted for their often extraordinary colors and striking forms. There are more than 3,000 described species of nudibranchs. The word “nudibranch” comes from the Latin nudus, naked, and the Greek βραγχια, brankhia, gills. [via]
by Adam Cole
English critic Samuel Johnson once said of William Shakespeare “that his drama is the mirror of life.” Now the Bard’s words have been translated into life’s most basic language. British scientists have stored all 154 of Shakespeare’s sonnets on tiny stretches of DNA.
It all started with two men in a pub. Ewan Birney and Nick Goldman, both scientists from theEuropean Bioinformatics Institute, were drinking beer and discussing a problem.
Their institute manages a huge database of genetic information: thousands and thousands of genes from humans and corn and pufferfish. That data — and all the hard drives and the electricity used to power them — is getting pretty expensive.
“The data we’re being asked to be guardians of is growing exponentially,” Goldman says. “But our budgets are not growing exponentially.”
It’s a problem faced by many large companies with expanding archives. Luckily, the solution was right in front of the researchers — they worked with it every day.
“We realized that DNA itself is a really efficient way of storing information,” Goldman says.
DNA is nature’s hard drive, a permanent record of genetic information written in a chemical language. There are just four letters in DNA’s alphabet — the four nucleotides commonly abbreviated as A, C, G and T.
When these letters are arranged in different ways, they spell out different instructions for our cells. Some 3 billion of those letters make up the human genome — the entire instruction manual for our existence. And all that information is stuffed into each cell in our bodies. DNA is millions of times more compact than the hard drive in your computer.
The challenge before Goldman and his colleagues was to make DNA store a digital file instead of genetic information.
“So over a second beer, we started to write on napkins and sketch out some details of how that might be made to work,” Goldman says.
They started with a text file of one of Shakespeare’s sonnets. In the computer’s most basic language, it existed as a series of zeroes and ones. With a simple cipher, the scientists translated these zeroes and ones into the letters of DNA.
And then they did the same for the rest of Shakespeare’s sonnets, an audio clip of Martin Luther King Jr.’s “I Have a Dream” speech, and a picture of their office. They sent that code off to Agilent Technologies, a biotech company. Agilent synthesized the DNA and mailed it back to Goldman.
“My first reaction was that they hadn’t done it properly, because they sent me these little tiny test tubes that were quite clearly empty,” Goldman says.
But the DNA was there — tiny specks at the bottom of the tubes. To read the sonnets, they simply sequenced the DNA and ran their cipher backward. All the files were 100 percent intact and accurate.
They published their results in the journal Nature, joining other groups who have experimented with DNA storage. George Church, a geneticist at Harvard who helped start the Human Genome Project, encoded an HTML file of his latest book into DNA earlier this year.
Goldman and Birney’s method included greater redundancies and overlapping stretches of DNA to prevent against errors. They say the process would be easy to scale up.
If you took everything human beings have ever written — an estimated 50 billion megabytes of text — and stored it in DNA, that DNA would still weigh less than a granola bar.
“There’s no problem with holding a lot of information in DNA,” Goldman says. “The problem is paying for doing that.”
Agilent waived the cost of DNA synthesis for this project, but the researchers estimate it would normally cost about $12,400 per megabyte.
“It’s an unthinkably large amount of money … at the moment,” Goldman says.
Goldman and other scientists who are dabbling in DNA storage know that DNA synthesis costs are dropping rapidly. In a decade or so, they say it may be more cost effective for large companies to keep a DNA archive than to maintain and update a roomful of hard drives.
This is the coolest thing I’ve ever read.
Why Are Chimps Stronger Than Humans?
Even though they’re quite a bit smaller, chimps harbor exceptional strength. The reason why may come down to the difference between a Fabergé egg and a hand-dipped Easter egg: fine details.
Our muscles aren’t that much different in size from a chimp’s, but we have many more nerves feeding each one. This means we can exert much finer motor control and flex our muscles in many increments. Our motor control system also limits the degree to which we can flex our muscles in order to protect our fine motor control. A chimp has no such safeguard.
They also have longer muscle fibers (which can exert more force) and have been molded by evolution to maximize strength. For a chimp, with fewer nerve endings connecting to its longer muscles, it’s a more all-or-nothing extreme rage flex. I also wasn’t aware of their connection to Lithuanian knife smugglers, so watch out for that.
What would it be like to fight a chimp? One biologist described it like so:
Picture fighting a 300-pound olympic weightlifter with the reflexes of a hockey goaltender, whose main goal is to rip your face off your skull.
But can it master the fine motor control necessary to play Angry Birds?! I rest my case.
THERE IS A REASON I DON’T LIKE CHIMPS. I’M NOT CRAZY.
Nabokov on Kafka on Insects
Vladimir Nabokov, celebrated author of Lolita, and other novels, was not merely a writer. Not that being a writer is any sort of a “mere” thing, but go with me here. Nabokov was a professionally-trained entomologist, a lifelong student of insect biology.
He curated Harvard’s butterfly collection, contributing a great deal to the practice of lepidoptery and even getting parts of his work published in our day and age. Nabokov was a fan of Franz Kafka’s The Metamorphosis, the story of Gregor Samsa, who turned into a bug. That’s Nabokov’s teaching copy of Kafka’s book up there, scrawled with notes. Nabokov lectured on Kafka, and using his knowledge of insects he offered a theory as to what kind of bug Gregor may have become (not a cockroach as usually assumed):
Now what exactly is the “vermin” into which poor Gregor, the seedy commercial traveler, is so suddenly transformed? It obviously belongs to the branch of “jointed leggers” (Arthropoda), to which insects, and spiders, and centipedes, and crustaceans belong. If the “numerous little legs” mentioned in the beginning mean more than six legs, then Gregor would not be an insect from a zoological point of view. But I suggest that a man awakening on his back and finding he has as many as six legs vibrating in the air might feel that six was sufficient to be called numerous. We shall therefore assume that Gregor has six legs, that he is an insect.
Next question: what insect? Commentators say cockroach, which of course does not make sense. A cockroach is an insect that is flat in shape with large legs, and Gregor is anything but flat: he is convex on both sides, belly and back, and his legs are small. He approaches a cockroach in only one respect: his coloration is brown. That is all. Apart from this he has a tremendous convex belly divided into segments and a hard rounded back suggestive of wing cases. In beetles these cases conceal flimsy little wings that can be expanded and then may carry the beetle for miles and miles in a blundering flight … He is merely a big beetle.
Nabokov also offered this nice note to the Joes and Janes in the audience:
Curiously enough, Gregor the beetle never found out that he had wings under the hard covering of his back. (This is a very nice observation on my part to be treasured all your lives. Some Gregors, some Joes and Janes, do not know that they have wings.)
Nabokov isn’t the only entomologist who has studied Kafka’s work. Donna Bazzone of St. Michael’s College in Vermont wrote about the impossible biology of an insect the size of Gregor Samsa, based on the study of thousands of insect species:
None could be as big as the “new Gregor.” If the body with its exoskeleton were to scale up to human size, it would be so heavy that even appropriately sized legs and musculature could not support it. Such an insect could not move. Also, because insects do not have a respiratory system with tubes connecting to internal lungs that have large absorptive areas, a giant like Gregor the roach would not be able to get enough oxygen to survive. Furthermore, our circulatory systems are powered by a large muscular heart that sends blood to all cells in the body through an elaborate network of blood vessels. Insects lack such a sophisticated circulatory system, so if you scaled the body to human size, insect blood (containing oxygen and nutrients) wouldn’t be able to reach all cells.
I always knew something bugged me about that story.
Thanks to Open Culture for the Nabokov book link that sent me down this rabbit hole.
I wonder if Kafka intentionally wrote him as a beetle? The implication of having undiscovered wings is interesting…. As is the fact that Gregor-beetle would die due to an insufficient circulatory system. Thank you, Nabokov.
“But I am very poorly today and very stupid and hate everybody and everything.”
- Charles Darwin, in a letter dated October 1, 1861 [x]
I know I’ve reblogged this before, but.
Darwin sounds like he would fit right in on tumblr.
I don’t know why but that makes me really happy.
The Science of Halloween: The Salem Witch Trials
In the winter of 1692 in the Puritan settlement of Salem, Massachusetts, eight girls contracted a strange illness with terrifying symptoms—incoherent screaming, hallucinations, crawling skin, contortions and convulsions… When physicians could find no medical cause for their behaviour, witchcraft was suggested, and then accusations began to fly. What followed was the infamous Salem Witch Trials, which took the lives of twenty people and imprisoned many more. But what was the true cause of the mania? Perhaps the most intriguing and plausible theory—first proposed by Linda Caporael in 1976—suggests that the girls were suffering from ergot poisoning. Ergot (Claviceps purpurea) is a fungus that infects grain crops and forms a hallucinogenic drug—LSD is derived from it, and it’s thought to be linked to many bizarre occurrences throughout the middle ages, including the “Dance of Death.” When ingested, most often through bread, ergot releases a potent mycotoxin that cause victims to suffer headaches, paranoia, convulsive fits, burning and itching skin, vomiting, and hallucinations, which are fairly consistent with the symptoms of Salem’s “witches.” Moreover, ergot thrives in a cold winter followed by a warm, humid spring, and weather records show that in 1691, Salem boasted these very conditions. So, although there’s no way of knowing with absolute certainty, it seems that ergot poisoning was a strong contributing factor to the trials. Since Salem was brewing with inequality, fear of native Indians, bitter land disputes and sexual repression, it’s likely that all ergot did was provide a catalyst for an already volatile situation. There were no witches after all—but perhaps the trials are all the more terrifying because they weren’t the product of supernatural evil, but instead of ordinary human evil.
Minimal Posters - Muslim Scientists Who Changed The World.
Honoring the contributions of Muslim scientists from history to the modern era, with this always-awesome collection from Hydrogene.
New Kenyan Fossils Shed Light On Early Human Evolution
ScienceDaily (Aug. 8, 2012) — Exciting new fossils discovered east of Lake Turkana confirm that there were two additional species of our genus — Homo — living alongside our direct human ancestral species, Homo erectus, almost two million years ago. The finds, announced in the scientific journal Nature on August 9th, include a face, a remarkably complete lower jaw, and part of a second lower jaw.
Researchers from the University of Michigan School of Kinesiology and the U-M Health System looked at college students with and without a history of concussion and found changes in gait, balance and in the brain’s electrical activity, specifically attention and impulse control, said Steven Broglio, assistant professor of kinesiology and director of the Neurotrauma Research Laboratory.
“The last thing we want is for people to panic. Just because you’ve had a concussion does not mean your brain will age more quickly or you’ll get Alzheimer’s,” Broglio said. “We are only proposing how being hit in the head may lead to these other conditions, but we don’t know how it all goes together just yet.”
To begin to understand how concussions might impact brain activity and its signaling pathways, researchers asked the participants to perform certain tasks in front of a computer, and took images of their brains. The brains of the nonconcussed group showed a greater area of electrical activation than the participants with a history of brain injury.
In the next phase of study, researchers will look at people in their 20s, 40s and 60s who did and did not sustain concussions during high school sports. They hope to learn if there is an increasing effect of concussion as the study subjects age.
Science has prevailed over injustice in the state of New Jersey, where all jurors will soon learn about memory’s unreliability and the limits of eyewitness testimony. According to instructions issued July 19 by New Jersey’s Supreme Court, judges must tell jurors that “human memory is not foolproof,” and enumerate the many ways in which eyewitness recall can be distorted or mistaken. Cognitive scientists who study memory have celebrated the new requirements. “Eyewitness identification evidence is seen by jurors as being trustworthy and reliable,” said psychologist Charles Brainerd of Cornell University, who specializes in memory. “The science shows exactly the opposite.” The guidelines were prompted by State v. Henderson, in which the New Jersey Supreme Court overturned the conviction of Larry Henderson, an accused murder accomplice whose identification from a lineup was unduly influenced by police. Though egregiously unjust, Henderson’s case was hardly unusual: Eyewitness misidentification is the most common cause of wrongful conviction in the United States. Of prisoners exonerated by DNA testing, some 75 percent were mistakenly identified. (via Science of Eyewitness Memory Enters Courtroom | Wired Science | Wired.com)
I find the idea that memory is so fallible deeply unsettling.
The Physics of Swimming
With the 2012 Olympics now under way, swimming has been labeled, unsurprisingly, as one of, if not the, most competitive sport this time around. Thus, Quantumaniac wanted to share a scientific approach to swimming to give our readers a clue what to watch for when they see the events. Let’s start from the beginning of a race and go from the push-off to final stretch - scientifically of course:
The push-off: Basically, a swimmer wants to reduce drag resistance as much as possible by minimizing their surface area. As the body assumes a streamline position and is forced off the wall, the sleeker the body, the less drag produced. While pushing off the wall, the body should be submerged and facing the bottom of the pool. The swimmer should be flat and streamline in the water, with the feet swept back. The push-off is the same for all the strokes, except the backstroke, in which the body should be facing the ceiling. When the body begins to loose speed and float to the surface, the kick and first stroke is applied. The kick helps propel the body through the water, while the stroke helps pull it.
The stroke: Each stroke and pattern is unique. The physics of each stroke is similar, so let’s discuss Freestyle. Freestyle begins with the catch, a motion which allows the swimmer’s hand to engage the water. As the arm enters the water; first, the body rolls downward to the same side. Second, the shoulder pushes forward from the chest. These two movements mimic a person stretching to reach something beyond grasp. At this point the arm rolls counterclockwise and sweeps outward, using the latissimus muscle. When done correctly, a solid feel of water pressure against the hand is experienced. The power phase of the stroke drives the arm inward and backward to the hip. Finally, the recovery brings the hand back to the catch phase of the pulling pattern.
The turn: For freestyle, the second to last stroke ends at the hip and stays there while the body follows the last stroke into a summersault. When the body rotates, a tight ball is used to make the turn quick. Physics tells us that as an object is rotating, velocity is increased as the moment of inertia is decreased (i.e. the smaller the sphere, the faster the velocity of the turn). When the body has rotated 180 degrees, the feet are extended to the wall and the push-off from the wall propels the body into another cycle.
Symmetry plays an important role in swimming. If a body and its motion are not symmetrical, the body tends to move in the direction with greater force. For example, a person who pulls hard on the right side will move in a counterclockwise circle. A good swimmer balances the body, the forces exerted, and the forces produced by the body. An imaginary line that passes down the center of the face and ends between the legs is the most common line of symmetry.
For freestyle, before the power-phase the arm rotates counterclockwise and then sweeps outward. A common mistake is for the arm to rotate clockwise and them pull, which unfortunately causes the arms to pass the line of symmetry, causing the arms to pull water that is disrupted by the body itself, and leads to a very inefficient stroke. The arms that pull to the outside of the body are pulling water that is not disturbed by the body, leading to a greater force applied.
Swimmers also get into a rhythm with their kicking and pulling. A swimmer with a set rhythm and lots of practice will use less energy to travel the same distance as a swimmer with no rhythm. If you’ve ever seen an Olympic swimmer, you will notice a set rhythm, however, compare them to a beginner and an obvious difference in the rhythm will be noticed.
Swimming, like most sports, has evolved by leaps and bounds over time. As the sport evolved, the idea of square movement changed to curved paths. Good swimmers now use sculling actions to utilize lift forces. Sculling is a back-and-forth movement of the hands and forearms that provides almost constant propulsion. This is Bernoulli’s Principle at work. The principle of “foil-like” objects moving through a fluid at high speeds with small angles to the flow and a large lift forces is generated, while the drag forces are minimized. The lift forces are caused by the fluid traveling further and faster around the more curved side than the less curved side. Essentially, the hand acts as a foil.
Bernoulli’s Principle is only one explanation of the kinetics of the lift force. Drag and lift both contribute to the net force produced by the hand. Ideally, the combination of lift and drag forces is such that the resultant force is in the desired direction.
In the aquatic environment, propulsion is generated by accelerating water. The momentum, P, of a mass of water, m, traveling with velocity, v, is P = mv. By forcing water backward with a momentum, the resultant propels the swimmer forward.
The pushed-away mass of water acquires kinetic energy as a result of the work done by the swimmer on the pushed-away mass of water. Part of the total work of the swimmer is converted into kinetic energy of the water, rather than forward speed of the swimmer.
By combining these two ideas, a body is propelled through the water by giving water a momentum in the opposite direction and propelling the body forward. In order to give the water a momentum in the opposite direction, the hand manipulates the water and puts lift on the hand and momentum on the water in the opposite direction.
We already know that as the body moves through the water, it disrupts the flow of water. As the body moves forward, water is given a momentum backwards and travels until the velocity is 0. The water behind the swimmer follows the motion of the swimmer and creates drag. If two people are swimming in a straight line with one in front of the other, the person in the back is being pulled behind the swimmer in the front by a small drag force. As the swimmer in the back slides their hand into the water for the catch, they are placing their hand into water that already has a momentum. For this reason the person in the back does not have to work as hard to travel the same distance.
The swimming pool has floating lane lines that typically divide the pool into six swimming lanes. Within each lane, the motion of swimming is counterclockwise (i.e. swim down on the right and return on the left). These floating lines keep waves to a minimum by knocking them down. They also minimize the momentum of a body of water after is has been pushed backwards. The water vortex breakup when they come into contact with the lines.
Despite having protected status, the biodiversity in a large number of tropical forests is still continuing to decline, a study has suggested. The authors said the findings should cause concern because the areas have been seen as a final refuge for a number of threatened species. Habitat disruption, hunting and timber exploitation have been seen as signs of future decline, they added. The findings have been published online by the science journal Nature. “The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon,” the international team of research wrote. “Many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses.” (via BBC News - Protected tropical forests’ biodiversity ‘declining’)
The processes that drive evolution are not known for their speedy nature. Human ancestors, for instance, made the jump to hairless bodies as little as 1.2 million years ago. That’s a long time for a fairly routine adaptation. Of course, when the environment places extreme pressure on an organism to adapt or die, the process of natural selection can be greatly accelerated, as with the famous peppered moths of soot-blackened England, which evolved dark wings within half a century in order to be camouflaged on blackened tree trunks.
This Australian sea star may be a record-holder, though. After being geographically isolated (part of the “Five Fingers of Evolution” we saw in this TED Ed video) from their relatives, they were forced to shift from sexual reproduction to asexual reproduction in just 14,000 years! That’s the blink of an eye for evolution, and like warp drive for a change that significant.
The power of natural selection never ceases to amaze …