Basic biology has it that girls are girls because they have two X chromosomes — the things inside cells that carry our genes. Boys are boys because they have one X and one Y. Recently, though, there's been a lot of debate in scientific circles about the fate of that Y chromosome — the genetic basis of maleness.
Very early in the evolution of the Y chromosome, explains Dr. David Page, a geneticist at the Massachusetts Institute of Technology, something pretty dramatic happened: The ancestral Y lost most of its genes. And scientists basically ignored the little that was left.
"The Y chromosome was essentially written off as the runt of the human genome," Page says, "as a sort of genetic wasteland that didn't really merit anyone's serious attention."
When the Y did get any attention, it wasn' t good news. Some scientists, like geneticist Jennifer Graves at La Trobe University in Melbourne, Australia, speculated that the Y might be destined to just keep, sort of ... rotting away.
"As soon as it becomes a male-determining chromosome, then the rot sets in," La Trobe says. "That's kind of the kiss of death for that chromosome" — meaning the Y chromosome could be headed toward oblivion, completely disappear.
But other scientists, including Page say: Not so fast. Step away from my Y chromosome.
"I've really spent the better part of my career defending the honor of the Y chromosome in the face of insults of this sort," Page says.
For the Y, size really doesn't matter, he says. Page has done a detailed analysis of the chromosome's evolution and says the string of genes has been solidly stable now for millions of years.
"The idea that the Y chromosome might disappear altogether, possibly taking men with it — I think that idea has now been firmly dismissed," he says.
In fact, the relatively few precious genes that are left on the Y look like they're special — very special.
"There are genes on the Y chromosome that are active throughout every nook and cranny of the body," Page says, "the skin, the blood, the brain, the lungs — you name it. They look to be sort of global entrepreneurs within the human genome. They are sort of master regulators."
Still, Jennifer Graves remains skeptical.
"I don't think that one can assume just because they're there and they do something useful they'll be there forever and ever," she says. "A small accident could tip it over the edge, or the evolution of a new sex-determining system that works better."
Graves says she is always surprised by the ferocious reaction she gets to any suggestion that the male chromosome might be vulnerable.
"I've been accused in print of being, you know, a ball-breaking feminist," she says. "Well, no — not really. I'm just pointing out that things change and evolution is wonderful, and it can do thing lots of different ways."
Graves has a theory about why the reaction is so intense, especially among men.
"There's some deep-seated insecurity that men have about their Y chromosomes," she says, half-joking. "When I give lectures about the demise of the Y chromosome, I see men sort of hunching up into this protective stance as though I'm physically attacking them."
And there's a twist in all this. Even if the Y chromosome is here to stay, that may be something of a double-edged sword for men. Even if those master genes on the Y chromosome are important, they may also help explain why men are more prone to certain diseases than women are — and tend to live shorter lives.
Jan Dumanski, of Uppsala University in Sweden, and his colleagues recently reported, for example, a possible link between the Y chromosome and an increased risk for lots of cancers. He sees the human Y chromosome as "the Achilles heel for men."
"It's making us men," Dumanski says, "but also causing us some trouble when we are getting older."
Clearly, our relationship with Y continues to be complicated. And it's not all about size.
At first glance, there's not much to the new video for the song "No Werewolf," from the Los Angeles garage rock band Allah-Las. But the longer you watch, the more mesmerizing it becomes.
The video opens with a simple spinning wheel in stark black and white. A hand appears, and as the wheel continues to whirl, beautiful shapes and lines appear, bloom and grow, then give way to new figures, at times resembling a vinyl record. It's all the work of Russian sculptor Mikhail Sadovnikov, an artist who makes what he calls the "dance on the circle" with a potter's wheel and clay.
"No Werewolf" is a cover of a 1960 song by the band The Frantics. The surf-rock instrumental appears on The Allah-Las' upcoming sophomore full-length, Worship The Sun, out Sept. 16.
This is a trick question. Where would you expect to find the greatest variety of birds?
Downtown, in a city?
Or far, far from downtown — in the fields, forests, mountains, where people are scarce?
Or in the suburbs? In backyards, lawns, parking lots, and playing fields?
Not the city, right?
"Everything I have learned as a conservation biologist tells me cities are bad for biodiversity," writes John Marzluff, of the University of Washington.
We all know this. Anyone who goes to downtown Chicago, Toronto, Seattle, L.A., Boston or New York will see the same five birds over and over: sparrows, starlings, mallards (ducks), geese, and, of course, street pigeons. Same goes for downtowns in Europe, Asia and South America. These five bird types are always there, always the same, never surprising. Rather than yawn, scientists have a category for this: "biotically homogenous." We've made cities. They've moved in.
A Seattle Experiment
But now comes a surprise. Actually, several surprises. When John Marzluff and his students went to downtown Seattle to count bird species, within the first 10 to 15 minutes they spotted pigeons, finches, sparrows, crows and an occasional hummingbird. Their count was 10 to 15 different kinds of birds — not many, but they expected that.
When they went the other way (to the far edge of the metropolitan area near the Cascade Mountains, where there is mostly forest, protected parks, reservoirs — and humans are sparse), in the first 10 to 15 minutes, they found a very different set of birds (woodpeckers, wrens, warblers, chickadees ...). In all, 20 different species - more, but not many more than downtown.
Then they went to the in-between zone, the Seattle suburbs, where they expected an in-between count, something like 12 different kinds of birds. But that's not what happened.
"We were astonished," Marzluff writes. The suburban count (again in the first ten minutes) was "30 or more species," says Marzluff, some from downtown, some from the mountains, but also a spectacularly new samples of "violet-green swallows, willow flycatchers, killdeer, orange crowned warblers, American goldfinches, and Bewick's wrens ... [plus a few]white crowned sparrows." The suburbs produced, by far, the most biologically diverse collection of birds.
What? This region that's all sprawl, a hodgepodge of strip malls, yards, highways, parking lots, hedges, fences, is "a mecca for birds?" More than a forest? No way, thought Marzluff. So he counted again. Then again. And after checking and compiling "more than 100 locations in and around Seattle," he writes, he and his team discovered "a consistent, but unexpected relationship between the intensity of development and bird diversity."
To his great surprise, Marzluff concluded that, "the greatest diversity was not in the most forested setting. Instead, bird diversity rose quickly from the city center to the suburbs and then dropped again in the extensive forest that eases Seattle into the high Cascades."
If you plotted it on a graph, bird biodiversity looks like this ...
He had just discovered, he writes, "subirdia." And that's the name of his forthcoming book, due this fall, called Welcome to Subirdia.
So what have suburbs got that forests don't? Suburbs, he says, offer a wide range of artificially designed garden habitats, providing a smorgasbord of nuts, fruits, seeds, insects and ponds, in dense concentrations. Because they are rich with different kinds of bird food, suburbs are rich with different kinds of birds.
In Leicester, England, one survey found 422 different plant species in a single garden. Another census of 61 private yards in Britain found 1,166 vascular plants, 80 different lichens, 68 varieties of moss.
But let's not get crazy about this: suburbs are not the birdiest zones on earth. Any patch of tropical forest, with its dazzling populations of plant and animal life, will trump a garden-rich suburb. But if you are comparing suburban bird diversity to temperate wild spaces — say the Cascades, the Smokies or the Adirondacks — the suburbs, shockingly, win.
Birds and 'burbs
And not just in Seattle. Marzluff writes that, "throughout Britain, in deciduous woodlands of California and Ohio, grasslands of Arizona, forests of Japan, and shrublands of Australia, moderate levels of urbanization also provide an abundance of various resources that increases the number of bird species beyond that found in either wilder, or more densely populated settings."
So, like 40 percent of America's humans, a big hunk of America's bird species have chosen to live the suburban life. It's a bird boom, I'm surprised to say, I had never noticed.
In his forthcoming book Welcome to Subirdia (to be released in September), Marzluff drops one last bomb — "a real stunner," he says. Every March, he spends a few days in Yellowstone National Park, up on the northern edge. That's a 2.2 million acre expanse of wild space — very, very big. In 2013, he counted 26 bird species there.
Then he got on a plane and headed east to New York City, and found himself along Sixth Avenue, where he saw the usual "house sparrows, European starlings, and rock pigeons." And when he reached Central Park, he entered and found some mallards and the geese, so the usual urban bird quintet was accounted for; but as he walked around, he spotted a cardinal, then a bluejay, then a white-throated sparrow, then a black-crested titmouse, then a Cooper's hawk, then some crows, some blackbirds, three varieties of woodpeckers, wood ducks, cormorants, red-tailed hawks, herons, mourning doves — altogether 31 species. He saw a greater variety of birds in Central Park than he did in Yellowstone. We all know New York attracts exotic people, but birds too? Wild and wide open spaces, apparently, offer no special advantages. "From a bird's perspective," Marzluff writes, "large park[s] created by human hands or by nature are not all that different." Huh.
Our guests today, Old Crow Medicine Show, were singing on the street in North Carolina 14 years ago when none other than Doc Watson came by and gave them his blessing. The band's Ketch Secor borrowed a Bob Dylan outtake and turned it into an anthem called "Wagon Wheel" that only got bigger when Darius Rucker recorded it. Since we last saw them they've became a part of the Grand Ole Opry and have a new album called Remedy. And Dylan sent them another fragment of a song, "Sweet Amarillo," to finish. It's part of our set today.