Smithsonian.com

A koala at Sydney Wildlife World (photo by Sarah Zielinski)

Many of the poster animals of Australia—kangaroos, koalas, wombats and wallabies, to name a few—are marsupials, animals best known for carrying around their young in a pouch. Marsupials can also be found in the Americas; in the United States, the Virginia opossum is the only one, but there are dozens of species in Central and South America.

Scientists trying to draw the marsupial family tree have been perplexed by contradictory evidence: DNA studies suggested that the Australian branch was an offshoot of South American animals that migrated to Australia when the two continents were connected and part of Gondwana. Fossil studies, though, seemed to show that some of the Australian marsupials had made their way back to South America.

In a new study in PLoS Biology, researchers from Germany set out to make a marsupial family tree using retroposons, a kind of jumping gene—pieces of DNA that are copied and pasted at random within the genome. The more closely related two species are, the more retroposons they will share.

Comparing the retroposons of the 21 marsupials showed that they all shared 10 jumping genes, thus confirming that they shared one ancestor. But the South American and Australian marsupials formed distinct groups; the Australians shared retroposons that their South American relatives lacked. The researchers were also able to determine that the South American branch was older (meaning that the Australian marsupials had come from South America) because the South Americans lacked two retroposons shared by everyone in the Australian branch.

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This fall, a different kind of coral reef will be on display in the National Museum of Natural History’s Ocean Hall. It’s not made out of the calcium carbonate skeletons of living coral. It’s made out of wool. And acrylic, and cotton, and whatever other fibers local yarn artists get their hands on.

The exhibit is part of the Hyperbolic Crochet Coral Reef, a project started by two sisters in Los Angeles who run the Institute for Figuring, an organization that educates people about math and science. In about 2003, they started making models of hyperbolic space, a kind of space with surfaces that look undulating and ruffly, like a leaf of ornamental kale or a piece of kelp. The discovery of hyperbolic geometry in the early 19th century revolutionized how mathematicians thought about space; it launched the study of non-Euclidean geometry, the kind of math that underlies general relativity. Many cosmologists think the universe’s shape may be best described using hyperbolic geometry.

The writer says that hyberbolic crochet (her works, above) can be "kind of addictive." (Photo courtesy of Helen Fields)

It’s a tricky concept to visualize – unless, it turns out, you use crochet. After a few years, the sisters started varying the patterns in their crocheted work, and the pieces of frilly mathematical space piled up until, one day, they noticed it looked like a coral reef. A project was born; with contributions from volunteer crafters, the reef has been displayed in museums in London, Dublin, New York, San Francisco and others. Now it’s headed for the Smithsonian.

So the other night, I went on an adventure in math, crochet and coral. About three dozen women turned up at the Yarn Spot, a store in Wheaton, Maryland. (The all-female crowd wasn’t unusual; the vast majority of the coral pieces have been made by women.) The Yarn Spot is one of 10 yarn stores in the D.C. area that are hosting workshops and crochet-along parties for the Smithsonian Community Reef.

Jennifer Lindsay, the program coordinator, talked about the history of the project, passed around sample pieces and explained how to crochet hyperbolic planes, pseudospheres and other shapes. Then she set us loose to crochet. People who needed to borrow a crochet hook or some yarn dug through one of Lindsay’s bins. Experienced crocheters crowded her to ask questions, while store owner Victoria Rothenberg took the beginners aside to teach them how to wield a crochet hook. A lot were knitters who are perfectly capable with two needles but flummoxed by the single hook of crochet (crocheting is, by the way, much easier).

The coral reef has moved away from the strict requirements of modeling hyperbolic space; crafters are encouraged to experiment with varying the shape, increasing stitches (which widens the fabric and makes it ruffle like a hyperbolic plane) as often as they want to, for example. This is just the way nature works, says Margaret Wertheim, one of the sisters behind the Institute for Figuring. “All these frilly and crenulated structures on the coral reef—sponges, nudibranchs—those are all basically imperfect hyperbolic variants.” Of course, the animal isn’t counting stitches, but it is varying its growth. “They have it in their DNA to grow like this, but it’s affected by their immediate environmental conditions.”

And you don’t have to stick to hyperbolic shapes; they will take crochet models of anything that sits on a coral reef, like clams and anemones. Heck, you don’t even have to stick to crochet. Knitting is welcome, too, as long as the product looks reef-like. Knitting is welcome, too, as long as knitters make hyperbolic shapes or combine knitting (or other fiber techniques like felting, tatting, embroidery, etc.) with crochet. Anyone can mail in pieces by August 30; the deadline for dropping pieces off at a local yarn store or at the museum hasn’t been set yet. The reef will be on display in the Ocean Hall from October 16, 2010 to April 24, 2011.

For more information on the Hyperbolic Crochet Coral Reef at NMNH, including how to contribute: http://www.mnh.si.edu/exhibits/hreef/index.html

Guest blogger, and knitter, Helen Fields has written about snakeheads and dinosaurs for the magazine and can be found at Hey Helen.

The Tesla Roadster's "gas flap" conceals the input for electricity (courtesy of flickr user TheNickster)

GM announced yesterday that their electric car, the Chevy Volt, will cost $41,000. The car can go 40 miles on its battery, after which a gas-powered generator will charge the battery and extend the vehicle’s range another 340 miles. The Volt isn’t the only choice for electric-car enthusiasts: the Nissan Leaf, an all-electric car with a range of 100 miles, will go on sale later this year. And the Tesla Roadster can be yours for a mere $101,500. The Smart Fortwo, Mitsubishi i-MiEV, Tesla Model S. The list keeps growing.

Electric cars may be part of our future, but anyone who thinks they’re saving the world from climate change by buying one hasn’t quite thought through the purchase. I’ll explain:

Yes, an electric car emits no greenhouse gases. But where does the car’s energy come from? The battery. And the battery’s energy, for now, comes from your home.

Where does your home get its electricity? Unless you buy your energy from an all-renewable source, like a wind or solar farm, your car is still emitting carbon into the atmosphere, albeit indirectly, and contributing to anthropogenic climate change.

You can check where your energy comes from with the EPA’s Power Profiler. Just input your ZIP code, select your power company and a profile is generated comparing your fuel mix with the national average. In my neighborhood, that means I get 45.1 percent of my energy from coal, pretty close to the national average of 49.6 percent. And it’s coal that’s the real worry here. Coal may be cheap and abundant, but it also produces more carbon dioxide than any other carbon-based fuel source.

That’s not to say that electric cars aren’t part of a carbon-free future. But they’re not going to get us there as long as we rely on fossil fuels, in any form, to power them.

New technology will let the human nose control wheelchair movements (courtesy of flickr user derek*b)

If you’re paying attention, there can be an awful lot of information encoded in a series of nose sniffs. In and out, long and short, strong and shallow. One sniff, two sniffs, three sniffs. Now engineers at the Weizmann Institute in Israel have capitalized on that variety of sniffs and created a device that lets severely disabled individuals use their noses to communicate through a computer and steer a wheelchair. (Their study appears this week in PNAS.)

Sniffing is controlled by the soft palate, that bit of tissue at the back of the roof of your mouth. It’s the part that closes off the nasal passages when you swallow. The Weizmann researchers theorized that people who could no longer control their bodies—quadriplegics and those with “locked-in syndrome” who are completely paralyzed—could still control their soft palate and their patterns of sniffing. The scientists created a device that measures nasal pressure and then translates that pressure into an electrical signal.

Healthy volunteers were able to use the device to play a computer game; their responses were only a bit slower than using a mouse or joystick. When the device was connected to text-writing software, several locked-in patients were able to write messages using the new device. One woman who had become locked in following a stroke seven months earlier was finally able to communicate with her family again. Her stroke had left her without the ability to even control her eye blinks, often a method of communication for patients of her type. A man who had been locked in for 18 years following a car accident was able to write his name after only 20 minutes of first trying out the device; he had given up on past attempts to use an eye tracker and found the new device “more comfortable and more easy to use,” he wrote.

When the device was hooked up to a wheelchair, quadriplegics were able to learn how to use it quickly enough that they could navigate a complicated maze with only 15 minutes of practice. Commands were given in sets of sniffs—two in or two out, for instance, to go forward or backward—to avoid having an accidental breath send someone out of control.

There are, of course, limitations to the device. Writing through sniffing is incredibly slow—only a few letters per minute—but that’s about the same rate at which locked-in Jean-Dominique Bauby wrote The Diving Bell and the Butterfly using eye movements. And not everyone may be able to control their soft palate; about 25 percent of healthy volunteers in an fMRI study did not have that control. But sniff control may soon become another technology to add to the toolbox for the severely disabled, letting more of them do things, like communicate with loved ones, that the rest of us take for granted.

Most of us use our GPS to navigate the freeways and city streets. But in Mali and Kenya, zoologist Iain Douglas-Hamilton has put global positioning to a far more interesting use—tracking elephants.

Douglas-Hamilton, founder of Save the Elephants, has weathered droughts, floods and even rhino attacks to study elephant behavior. He set the standard for elephant research with his first study 40 years ago, which documented elephant social behavior in Tanzania through monitoring births, deaths and migrations. He has continued to develop innovative approaches to research and conservation in addition to becoming a leading voice against elephant poaching and the ivory trade. (His studies of elephant migration in Mali were the subject of a 2005 Smithsonian article.)

Iain Douglas-Hamilton (courtesy of the Indianapolis Prize)

Douglas-Hamilton’s study of Malian elephant migration is ongoing—he recently partnered with Google Earth to show the real-time location of his elephant subjects via satellite images—and he is also tracking elephants in the Samburu region of northern Kenya. Douglas-Hamilton was recently named the 2010 winner of the Indianapolis Prize for animal conservation and will lecture at the National Zoo on September 29. He spoke with Jessica Righthand.

What changes have you seen recently in the lives of the elephants you study in Mali and Samburu?

Since 2005, elephants in Samburu were living in as near as it gets to an elephant paradise. But things started changing in 2008, and we noticed an increase in poaching for ivory. We then had a severe drought that lasted until the end of 2009. The rains failed, and many more elephants died than usual, both of drought and from poaching. Then the rains came, and a ferocious tsunami-like wall of water swept down the river. It swept my research camp away, and also my wife’s camp (Oria Douglas-Hamilton runs a small safari camp called Elephant Watch Safaris). However, the good side of the rain was that there was plenty of grass that grew.

During the drought, there was simply nothing left for the cattle to eat, so all the nomadic people invaded the national reserve, where the elephants lived, because that was the only place they could find grass. Thousands of their cattle died despite this, but the wild animals were already suffering from this severe drought and from poaching and now had this influx of cattle. The Samburu elephant population had been increasing for a good twenty years or more. The drought checked the increase.

What about in Mali?

In Mali, the desertification is at a far more advanced stage than it is in northern Kenya. In 2009, there was a severe drought there too, and the one source of water on which the Mali elephants depend during the dry season, Lake Banzena, dried up completely. We had a panic last year in May because the rains had not arrived. There was no water left for the elephants to drink, and we wondered what was going to happen to them. We went into a crash program to build them a drinking trough and to pump water up from underground. So that trough was made and set in concrete, and as the concrete was drying, the rains came. We were saved by the rains!

But both areas are connected by one thing, which is nomadic people, and in both cases the overstocking of livestock has greatly degraded the habitats outside the protected areas of Samburu and adjacent Buffalo Springs. But in Mali, there’s no protected area, and the land is far more degraded than in Samburu. We’ve still got to solve those problems.

How does your approach to conservation have to differ from Samburu to Mali?

I think our approaches have differences and similarities. The similarities are that in both places the people who live there are pasturers and nomads predominantly, with scattered agriculture, so they’re also both peoples who are relatively tolerant towards elephants. In Samburu, though, there was a brief period when there was severe ivory poaching back in the 1970s and 1980s. That did not happen in Mali. In Mali, there’s never been severe poaching for ivory.

It also differs because of the behavior of the elephants. The defining feature of the elephants in Mali is their migration. It’s the be-all and end-all of their existence. And anyone who wants to look at their future has to look at that migration. That’s why our radio-tracking project there is absolutely of the first importance.

And do you do the same radio tracking in Samburu?

We do it on a much more massive scale in Samburu. Samburu is a much more complex environment in a way than Mali. In Mali, we’ve got something like 500 elephants. In Samburu, we have 7,500 elephants. In Mali, you have no effective protected area. In Samburu, you’ve got a kaleidoscope of areas of different land use owned by different ethnic groups, all of which represent a different risk or benefit to the elephants. There are many more people, many more elephants, and they’re all interacting, and elephants are only one of the many species of wildlife that exist in Samburu. Unfortunately in Mali, everything else has pretty much been wiped out, except for a handful of gazelles, some baboons and some warthogs. But the elephants could be the focus for the regeneration of that area, and that’s our hope.

What does the future look like for the elephants in Samburu and in Mali, and in Africa in general?

In a bigger perspective, the real horror story at the moment is happening in the Congo, and I’ve just been hearing about enormous destruction due to the ivory trade. The majority of elephants in Africa are severely threatened by the ivory trade.

But it looks like the future is more secure for elephants in Samburu than in Mali. Because there are more elephants, there’s a much stronger tradition of conservation, there are a lot of very dedicated NGOs working and there is a government wildlife service, which is highly experienced and very well trained. The downside is that we could be vulnerable to another outbreak of ivory poaching. Having a lot of people means that there’s a far greater human/elephant conflict. But by and large, I’m optimistic that some of the really good folk doing good things will come out on top.