Monday, March 4, 2013

The Scientific American February 2013 contains the following iconoclastic articles:

New Simulations Question the Gulf Stream’s Role in Tempering Europe’s Winters

It's the flow of warm tropical water across the Atlantic that keeps European winters mild, right? Maybe not
For a century, schoolchildren have been taught that the massive ocean current known as the Gulf Stream carries warm water from the tropical Atlantic Ocean to northwestern Europe. As it arrives, the water heats the air above it. That air moves inland, making winter days in Europe milder than they are in the northeastern U.S.
It might be time to retire that tidy story. The explosion of interest in global climate has prompted scientists to closely study the climatic effects of the Gulf Stream only to discover that those effects are not as clear as conventional wisdom might suggest. Based on modeling work and ocean data, new explanations have emerged for why winter in northern Europe is generally less bitter than winter at the same latitudes in the northeastern U.S. and Canada—and the models differ on the Gulf Stream's role. One of the explanations also provides insight into why winter in the U.S. Northwest is warmer than it is across the Pacific in eastern Russia.
At the same time, recent studies have been casting doubt on the popular conjecture made a few years ago that melting of Arctic ice could “shut down” the Gulf Stream, thereby wreaking havoc with Europe'sweather. Yet the studies do suggest that climate change could at least affect thestrength of the Gulf Stream, which could lessen the impact of global warming on northern Europe.
....later on in the article they say the gulf stream theory is refuted.......

A Single Brain Cell Stores a Single Concept [Preview]

Each concept—each person or thing in our everyday experience—may have a set of corresponding neurons assigned to it which are described the two theories of memory - millions of cells widely distributed in the brain, or narrow simple storage - that are still in competition after several decades. New discoveries lend some support to the latter, but memory storage in the brain is still not understood. Show this to those who think "science" understands the brain. 

Is the Free-Radical Theory of Aging Dead? [Preview]

The hallowed notion that oxidative damage causes aging and that vitamins might preserve our youth is now in doubt
David Gems's life was turned upside down in 2006 by a group of worms that kept on living when they were supposed to die. As assistant director of the Institute of Healthy Aging at University College London, Gems regularly runs experiments on Caenorhabditis elegans, a roundworm that is often used to study the biology of aging. In this case, he was testing the idea that a buildup of cellular damage caused by oxidation—technically, the chemical removal of electrons from a molecule by highly reactive compounds, such as free radicals—is the main mechanism behind aging. According to this theory, rampant oxidation mangles more and more lipids, proteins, snippets of DNA and other key components of cells over time, eventually compromising tissues and organs and thus the functioning of the body as a whole.

Gems genetically engineered the roundworms so they no longer produced certain enzymes that act as naturally occurring antioxidants by deactivating free radicals. Sure enough, in the absence of the antioxidants, levels of free radicals in the worms skyrocketed and triggered potentially damaging oxidative reactions throughout the worms' bodies.
Show this one to those who think taking anti-oxidants helps prevent aging. In fact the whole understaning of he process of aging is now in doubt> 

Will Scientists Ever Be Able to Piece Together Humanity's Early Origins? [Preview]

New fossil discoveries complicate the already devilish task of identifying our most ancient progenitors
By Katherine Harmon 

mammals, do. This familiar yet strange individual is Lucy, a member of the species Australopithecus afarensis, who lived some 3.2 million years ago. She is one of the oldest creatures presumed to have strode on the evolutionary path leading to our species, Homo sapiens.
From a distance, you probably would have assumed her to be human. Although she stood only about a meter tall, with long arms and a small head, she walked, if perhaps slightly inelegantly, upright on two legs, as we, alone among living mammals, do. This familiar yet strange individual is Lucy, a member of the species Australopithecus afarensis, who lived some 3.2 million years ago. She is one of the oldest creatures presumed to have strode on the evolutionary path leading to our species,Homo sapiens.
When Lucy was uncovered in 1974, evidence of bipedal locomotion virtually guaranteed her kind a spot in the human family tree. And although scientists had an inkling that other branches of humans coexisted more recently alongside our own, early human evolution appeared to be a simple affair, with Lucy and the other ancient bipeds that eventually came to light belonging to the same lone lineage. Thus, the discoveries seemed to uphold the notion of human evolution as a unilinear “march of progress” from a knuckle-walking chimplike ape to our striding, upright form—a schema that has dominated paleoanthropology for the past century. Yet as researchers dig back further in time, our origins are turning out to be a lot more complicated than that iconic image would suggest.

...indeed, in the body of the article it is suggested that it is unrealistic to expect that the lineage of homo sapiens will ever be established. 

And finally:

Human and Grasshopper Ears Are Remarkably Similar

Katydid ear structures resemble those of humans
In a striking example of how two unrelated creatures can evolve similar traits, researchers have discovered that a rain—forest grasshopper has ears remarkably like those of humans and other mammals-even though its hearing organ is tucked into the crook of its front legs.
The insect, a yellow-orange-faced katydid (Copiphora gorgonensis) from Gorgona Island in Colombia, has ear structures that are similar to the human eardrum and cochlea. As sound waves approach the katydid's legs, they rock a thin membrane akin to a human eardrum. This membrane translates larger movements from air-pressure waves to smaller, more powerful motions in another structure called the cuticle plate. The plate, in turn, creates ripples in a fluid-filled chamber akin to an unfurled human cochlea. Inside this chamber, sensory cells are arranged like a keyboard from high-to low-frequency sensitivity, much like in humans.

C. gorgonensis's exquisitely evolved ear may help it avoid predators such as bats, says sensory biologist Fernando Montealegre-Z, now at the University of Lincoln in England and lead author of the study, which appeared in Science. The finding “is yet another remarkable demonstration of convergent evolution,” says Ronald R. Hoy, a professor of neurobiology at Cornell University, who was not involved in the work.
The efficiency of this minuscule system could inspire engineers to create microsensors based on the katydid’s ear design—for example, for use in hearing aids. Such sensors could be less fragile, smaller and more sensitive, potentially spurring applications we have not thought of yet.

...Of course the  credit is given to evolution. But one would like to knkow: are there other related insects that also have "ears" similar to humans? And if not, what is the pathway of gradual change that led to this unique structure in insects? 

The lesson for cautious thinkers: expect what the textbooks say today to be largely rejected tomorrow [or next year, or next decade.....].