【Phat Yeti出品】60-SECOND SCIENCE 官方听力文稿 + 讨论帖 （更新至：2008.03.07）

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60-Second Science_ July 23, 2008

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60-Second Science_ July 24, 2008
Parasites Permeate Ecosystems
A study shows that parasites can make up three percent of an ecosystem's biomass--and even outweigh the so-called top predators. Karen Hopkin reports.
When you think about an ecosystem, you usually think of the big animals that live there. The Serengeti’s ruled by lions. And estuaries are populated by fishes, birds, snails and maybe the occasional otter. But there’s more to an ecosystem than meets the eye. Because a team of scientists from the US and Mexico has found that parasites constitute a sizeable chunk of the biomass of an ecosystem.
The scientists catalogued and weighed all of the plants, animals and parasitic species living in three river estuaries. They found that in terms of sheer bulk, parasites represent about three percent of the biomass of these ecosystems. Pound for pound, one parasite—the trematode fluke that infects a certain snail—outweighs all of the estuaries’ birds, which are the ecosystem’s top predators. The results appear in the July 24 issue of Nature. That means that creatures you can’t see might be even more important to the health of an ecosystem, and to its balance of power, than the ones you can see. For example, in these estuaries, snails that are infected with trematodes outnumber those that are fluke-free. Now that’s what you call a controlling interest.
—Karen Hopkin

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60-Second Science_ July 25, 2008
Girls Equal Boys at Math
An analysis of performance on math tests finds that girls match boys. And no gender difference can be found among top performers either. Cynthia Graber reports
Remember when Barbie whined that “math is hard.” Maybe you got annoyed at hearing a popular female doll say that to little girls. Or maybe you also had a nagging suspicion that, in fact, boys are better at math. Well, the latest research is in, and the answer is a resounding no: boys are not more math savvy. The finding appears in the July 25 issue of the journal Science.
Janet Hyde at the University of Wisconsin-Madison led the study. The group dug through piles of information from seven million students tested through the No Child Left Behind program across ten states. Researchers had detailed personal info on the test takers. Researchers checked out math tests in different grades. They took the average. No difference. Some critics have said that the difference only shows up among the highest levels of math skills. So the team checked out the most gifted children. Again, no difference. From any angle, girls measured up to boys. Still, there’s a lack of women in the highest levels of professional math, engineering and physics. Some have said that’s because of an innate difference in math ability. But the new research shows that that explanation just doesn’t add up.
—Cynthia Graber

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60-Second Science_ July 28, 2008
Abundant Oxygen Indirectly Due to Tectonics
Bacteria oxygenated the atmosphere, but tectonics fed the bacteria. Karen Hopkin reports
Once upon a time, our atmosphere was a little thin on oxygen. Like, there wasn’t any. Then, about three billion years ago, a handful of bacteria figured out how to harvest the energy from sunlight to make themselves some food. In the process, they consumed carbon dioxide, and gave off oxygen. So the air filled with oxygen, and all was right with the world. If you’ve ever taken an intro biology course, you’ve no doubt heard the tale. Photosynthetic bacteria are the heroes who brought oxygen to our planet.
But maybe there’s more to the story than that. Because in the online issue of Nature Geoscience, researchers from Australia say: the bacteria didn’t act alone. The scientists looked at atmospheric oxygen levels throughout Earth’s history. And they found that the amount of oxygen in the air spiked each time smaller land masses collided to form a supercontinent, like Pangea. These massive pile-ups generated mountain chains, and as the mountains eroded, they released nutrients into the oceans, feeding the photosynthetic bacteria. So the young Earth and its inhabitants worked together to produce a planet where you can really find inspiration.
—Karen Hopkin

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60-Second Science_ July 29, 2008
Animals That Seek Out Alcohol
Researchers have found animals that go out of their way to get the equivalent of nine drinks a night. Cynthia Graber reports.
There are plenty of tales of animals finding some alcohol and getting tipsy. But those stories usually involve manmade beer or wine. There’s been no evidence of animals seeking out naturally fermented fruit in the wild—until now. Researchers stumbled upon the first example of animals looking for a drink in the Malaysian rainforest.
The scientists noticed a yeasty smell wafting from a local palm. They saw a frothy substance, like the head on a mug of beer. It turns out the palm’s nectar has as much alcohol as some beer does. Then scientists followed two tiny mammals – the pentailed treeshrew and the slow loris. The critters dip into the nectar several times nightly. They regularly guzzle the equivalent of about nine drinks a night—though they don’t display what we’d consider drunken behavior. And they act as the plant’s pollinator. The research appeared in the Proceedings of the National Academy of Sciences.
The pentailed treeshrew is a living version of an ancient mammal, a kind of relic of the mammals from which both shrews and primates –  and eventually humans – branched off. So this discovery could lend some weight to the hypothesis that our love of the hard stuff has a deep evolutionary history. I’ll toast to that.
—Cynthia Graber

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