Transcript

Science: Madagascar

Rick Weiss
Washington Post Staff Writer
Monday, January 28, 2008; 12:00 PM

Washington Post science writer Rick Weiss was online to discuss new plant species found in Madagascar on Monday, Jan. 28 at Noon ET.

He will also take questions about recent science news, including the topics of cloned meat and milk and stem cell research.

The transcript follows.

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Rick Weiss: Greeting everyone and welcome to today's chat. There's been a lot of interesting science in the news lately, from today's stories about the discovery of a weird new kind of plam tree in Madagascar and the close-shave fly-by of an asteroid that will happen tonight, to the recent stories about food from cloned animals and new ways to make human embryonic stem cells or their equivalents. I'm all ears (no, it's not from eating cloned burgers. That's just an expression), so let's get started!

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Arlington, Va.: Has there been a marked increase in discoveries with improved satellite technology and the Internet?

Rick Weiss: I am not aware of new species that have been discovered with the help of satellite technology, but as I learned as I reported out the palm story, satellite imagery certainly has helped clarify the rate at which environments are changing, mostly as a result of human activity. It is easy to see the vegetation changing (in the case of rice, for example, replacing forests)or disapearing (in the case of open pit mining, for example), both of which are very common in Madagascar, as well as spotting the many fires being set to clear land for these new uses. Satellites are getting very good at detecting evidence of insect damage and plant diseases, too, which in many cases can be caused or exacerbated by human activities. In short, with such good imagery, there is almost no excuse anymore for our continuing to do some of the destructive things we are doing.

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Herndon, Va.: Isn't this plant closely related to the Century Plant (Agave americana) at Longwood Gardens, PA?

The bloom and process is the same. Chuck

Rick Weiss: No, that is a common misconception, born perhaps of the common trait that both plants flower only after many years of growth and the fact that both have influorescenses (featuring many small flowers) rather than individual flowers. Also you can't make mescal or tequila from palm trees.

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Detroit, Mich.: How much deforestation is occurring in Madagascar? Is there a chance that much of there forests will be destroyed before a good accounting of new plants occurs?

Rick Weiss: People I spoke to who have been to Madagascar sound very upset by the high rate of deforestation going on there. They talk about the odds (high, they say) that many species will disappear before ever being discovered -- not just plants, but animals, too. That said, the island has one thing going for it: The most biologically rich and diverse part, which is the eastern side of the island, is also the most geographically rugged. There is a steep escarpment, rocky and difficult to clear or farm. So it will withstand human intrusions longer than the central plateau or the western drylands, which slop more gradually toward the sea.

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Lively, Va.: I have a vague recollection that the ginko tree was the only other plant to have a genus of which it was the only member... Or is the ginko in its own phylum?

Please help me remember my college botany.

Albert

Rick Weiss: Well, you've got me stumped there. The one thing I remember about Gingkos from my hgh school biology is that they are quite primitive, as evidenced by the fact that the veins in the leaves, as I recall, do not branch but are all roughly parallel to one another. That is a less than efficient vascular design (though geeze, it has not gotten in the way of their survival to modern times, it seems, and they seem to do amazingly well along heavily traversed streets thick with air pollution. Maybe, like cockroaches, these leftovers of an ancient time will outlast us all).

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Harrisburg, Pa.: I have long found Madagascar fascinating. Being isolated, didn't many of its plant and animal species develop independently from the rest of the world? I have found one finds some of the most interesting products of nature of Madagascar. My question: about how much of Madagascar has even been searched by scientists? Are the political leaders and population supportive of further research?

Rick Weiss: It is very interesting to look online at some of the sites that show how pieces of the earth's crust moved around 100 million years ago or so. You can see Madagascar, all by itself, even back then. A big piece of crust scrapes by off its east coast and drifts northward for 50 million years or more and crashes into central asia, to become the Indian subcontinet (and making the Himalaya in the process; a hell of a fender bender). Point is, yes, it's been its own piece of turf for a long time, so evolution took its own course there and made all kinds of exotic plants and animals in the process. There are some fledgling efforts to conserve parts of the island for tourism and for general biodiversity preservation, but it is incredibly poverty-stricken and it's not like the government has tight control over activities in the island's many hard-to-reach areas, so people are cutting down lots of trees for both survivial and commerce and plantng fields of crops just to get by.

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Washington, D.C.: Does the dramatically changing climate affect our discovery or understanding of new species?

Rick Weiss: I think the most salient thing that climate change is adding to our understanding of species (new or old) is the extent to which various species are able to adapt to change. It is already clear from satellites and land-based surveys that the northern-most boundaries for some temperate tree species, for example, as well as for some of the insects and birds that are associated with those plants, have already moved northward in recent decades, apparently as a result of warming temperatures. Still unclear, though, is how many (and which) species of various kinds will be able to really survive that shift, and how many will get left behind and perhaps go extinct.

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Herndon, Va.: Amazing that 2 unrelated plants from different continents are so similar in their VERY unusual blooming process. I suppose that places like Indonesia must have many unrecorded and unstudied species, since there's a lot more room there.

Rick Weiss: It is perhaps not surprising that plants with different origins would have settled on similar life-histories/reproductive strategies. This is the essence of what scientists call "convergent evolution," in which unrelated species find that similar tacks work for them. As it turns out, Madagascar has a very interesting living laboratory for convergent evolution on its arid West coast. Its so-called spiny forest features a wide variety of plants that resemble cacti, but which are not in fact in the cactus family. They have fleshy, water-preserving parts, they have prickers of various kinds and many share other attributes that make sense in a climate where water is scarce and sporadic. Many of them look like they must be close relatives of each other. But if you look at their DNA, you find they are from wholly unrelated families. They just converged on common survival strategies. Similarly, some plants flower when they are young, to make sure they get offspring before its too late. Others wait til they are old, then put everything they have into it. Various animals fall into these tow categories, too. Each approach has its advantages.

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Rockville: I had not heard about the asteroid close encounter for tonight. How close will it be?

Rick Weiss: Tonight's asteroid, which is about as wide as the length of three football fields, will pass about 334,000 miles from Earth, or about 1.4 times the distance to the moon. No chance it will hit us, but scientists say that of the hundreds of near-earth asteroids they are constantly tracking, none this big will pass this close until 2027. Astronomers and planetary scientists have been tracking this one with radar telescopes at NASA's Goldstone facility in Calif. and from Arecibo Observatory on Puerto Rico, to fine-tune their measurements of its trajectory and to look at its features. The longterm goal is to be better able to predict future possible impacts by asteroids and to design interventions that might be able to knock one off track if it looked like it might be heading for us.

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Rosslyn, Va,: I work for a conservation organization and just thought I'd chime in that satellite imagery is not usually directly helpful in finding exact locations of a species on the ground (especially plants, where with many species it can be hard enough making an identification in the field let alone using an aerial view). However, satellite data is an important input for identifying suitable habitat - i.e. places that are a good place to go out in the field and look for something.

Rick Weiss: Yes, thank you, I did not mean to imply that satellites are good for finding small-scale stands of individual species. WIth regard to detecting disease or insect damage, for example, the pictures I've seen involve scans of large areas of monocultures. But it was interesting for me to learn that the not-very-big rocky crag on Madagascar around which these weird palms are growing -- and indeed, the greenish splothces of the palms themselves -- are visible on Google Earth imagery. If the remaining 92 palms of this species were to disappear, we'd know it from the satellite shots.

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Sheridan, Wyo.: Are there any chances that the asteroid in question might be visible to us during its relatively close "pass by"?

Rick Weiss: The asteroid, which will be magnitude 11 tonight, will not be visible to the naked eye but amateur astronomers with telescopes that have at least a 3-inch aperture or even with good binoculars should be able to see it. For an introduction to what you might see, see this link, which also links to more detailed instructions from the Jet Propulsion Lab in Pasadena,

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Los Alamos, N.M.: Is there a way to get Tahina seeds?

Rick Weiss: The seeds are being distributed first to some big-name conservatories, including Kew Gardens in England and the Fairchild Tropical Botanic Garden in Coral Gables, Fla., to get the best odds of getting some trees going. If you are affiliated with an operation like one of these, you might be able to get something. I suggest you contact the folks at Kew (John Dransfield would be key) to find out more. But for amateurs, the seeds at this point are too precious to hand out or even sell.

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Rick Weiss: OK we are out of time. Thanks for participating!

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