国家地理
《国家地理》2009十大发现
转载科学网上的报道：美国《国家地理》评出2009年十大自然发现
重口味蚯蚓浮出土面
New varieties of the Lumbricus rubellus earthworm can eat hazardous waste, researchers reported in September 2008.
Above, the "reference" earthworms are normal, whereas the "stream" and "cottage" earthworms have evolved to survive in soils contaminated with high amounts of lead and zinc.
Photograph by Jane Andre
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Heavy Metal-Eating "Superworms" Unearthed in U.K.
James Owen
for National Geographic News
October 7, 2008
Newly evolved "superworms" that feast on toxic waste could help cleanse polluted industrial land, a new study says.
The lead-eating Welsh worms likewise use a protein to render the metal harmless inside their bodies, he added.
在英国发现的几种“超级蚯蚓”有望在重金属污染环境的恢复中贡献力量。这些蚯蚓是在不列颠和威尔士的几个废弃的矿地发现的，吞食铅、锌、砷和铜。经过蚯蚓消化之后排泄出来的重金属，可以被植物很好地吸收，收割这些植物后，留下的将是一片干净的土地。
用强x光轰击蚯蚓，可以使人们追踪其体内比盐粒小1000倍的重金属颗粒。科学家发现，arsenic-tolerant（这个怎么翻译才好）的蚯蚓能制造一种特殊的蛋白质使砷不参与体内的反应，从而保证了它们的安全。正因为这样或其他类似的本领，使这些“超级蠕虫”可以生活在高浓度重金属污染的区域，换了其他种类的蚯蚓，恐怕早就死翘翘了。
这项研究长远的目标是通过饲养、繁殖并把这些“超级蚯蚓”释放到受污染地区，改善土壤质量，并促使整个生态系统开始修复。一旦这些蚯蚓开始工作，植物也将随之发挥作用。而最终，我们希望能把植物中的重金属提取出来，换句话说，我们要把这些植物当成一座重金属矿山。
当然，愿望是美好的，但还有很长的路要走~~
0世界上最小的蛇
World’s Smallest Snake Discovered, Study Says
Scott Norris
for National Geographic News
August 3, 2008The world’s smallest snake—and perhaps the smallest possible snake—has been discovered on the Caribbean island of Barbados, a new study says.Many of the smallest snake species are found on oceanic islands—a pattern that holds true for other animals too.
世界上最小的蛇最近在加勒比海的巴巴多斯岛上被发现。这种线丝蛇的学名是Leptotyphlops carlae，长度大概十公分，可以舒服地蜷在一个25美分的硬币上。丝线蛇是世界上最小的蛇类，短而细，在土壤下挖洞生活，以昆虫幼虫为食。“海岛上的动物常常有或大或小极端的体型，这是因为它们占据了在大陆上原本属于其他动物的生态位。”发现这一新种的科学家Hedges解释道。他还在加勒比海的岛屿上发现了世界上最小的蜥蜴和最小的青蛙。从体型大小与繁殖策略的进化平衡（an evolutionary trade-off between size and reproductive strategy）上，这种蛇，也几乎是“可能”的最小蛇类。Hedges介绍，如果蛇的体型更小的话，它们将无法繁殖出足够大的，能独立觅食昆虫幼虫的后代。
然而也有学者提出，现在说Leptotyphlops carlae是世界上最小的蛇还为时过早。与这种蛇亲缘关系很近的几种蛇长度仅仅比之大几分之一英寸，而且这些长度数据仅仅来自几次观察和博物馆的标本，真实自然环境中的蛇的长度还了解不足。另外，即使现在这种蛇的长度最短，但其他蛇可能更加纤细，体积也更小。
Full story: http://news.nationalgeographic.com/news/2008/08/080803-smallest-snake.html
0两则野生动物保护的新闻
Newfound Monkey Species "Rarest in Africa," Experts Say
Steven Stanek
for National Geographic NewsAugust 4, 2008A recently discovered African monkey could soon be extinct, scientists report.
一种2005年刚刚发现的猴类新种如今陷入了极度濒危的境地。这种猴子学名为Rungwecebus kipunji，在坦桑尼亚南部高地和Udzungwa山脉地区被发现，当时人们以为这只是白眉猴的一种。2006年的DNA鉴定结果显示，这是一个全新的物种。根据近期的一次调查，这个濒危物种的数量仅有1117只，已经被国际自然保护联盟（IUCN）列为了“critical endangered（极危）”级别。全文链接：
http://news.nationalgeographic.com/news/2008/08/080804-rarest-monkey.html
"New" Killer Whale Types at Risk From Antarctic Warming
John Roach
for National Geographic News August 04, 2008Two newly identified types of killer whales that hunt prey off of Antarctic sea ice risk losing food sources to global warming and melting, according to a new study on the whales’ movement patterns.
之所以在New上面加一个双引号，是因为新发现的这两种类型的杀人鲸还没有在科学上被认为是新种，尽管有科学家的观察发现它们有截然不同的外形、食物、体型大小、栖息场所，甚至是发声法，最关键的是，这些差别造成了它们之间从不交配繁殖。直到上个世纪七十年代，人们还都认为杀人鲸（也称为虎鲸、逆戟鲸）都属于一个物种，生活在南极到北极之间的广大海洋，捕食一切它们能找到的猎物。这种印象直到研究者们在北太平洋发现了三种类型的杀人鲸之后才开始改变。第一种杀人鲸生活在破碎的冰块下面捕鱼为生；第二种生活在大块的浮冰下面，捕食海豹、企鹅等动物；第三种，也是研究的最多的一种杀人鲸，生活在广阔大洋中，主要捕食小须鲸。对于前两种杀人鲸来说，地球变暖使极地冰川融解将对它们的生存造成极大的威胁。全文链接：http://news.nationalgeographic.com/news/2008/08/080804-antarctic-killer-whales-missions.html
0NG news:Oldest Live-Birth Fossil Found; Fish Had Umbilical Cord
Oldest Live-Birth Fossil Found; Fish Had Umbilical Cord
最早的胎生化石发现；鱼有脐带
Carolyn Barry in Sydney, Australia
for National Geographic News
May 28, 2008
http://news.nationalgeographic.com/news/2008/05/080528-mother-fossil.html
Remains of the world’s oldest known mother have been unearthed in the Australian outback, scientists say.
The remarkably well-preserved fossil—about 375 to 380 million years old—shows an embryo connected to its mother fish by an umbilical cord.
It is the earliest evidence of a vertebrate giving birth to live young, shifting back the date some 200 million years, said John Long, head of sciences at Museum Victoria in Melbourne, Australia, and lead author of a new study describing the find.
科学家宣布，世界上最古老的母亲遗骸已经在澳大利亚内陆出土。
这块保存的非常完好的化石——大约有3.75到3.80亿年——展现了一个通过脐带连接到母鱼身体的胚胎。
这是脊椎动物活体出生的最早证据，将时间往前移了大约2亿年，John Long介绍道。他是澳大利亚墨尔本维多利亚博物馆的首席科学家，也是这一发现研究中的第一作者。
(See a prehistoric time line.)
The fossil is also the earliest record of vertebrate sex, since live birth occurs when an ovum, or egg, has been fertilized internally by male sex cells.
"Having such advanced reproduction for a fish that primitive is amazing," Long said.
Evidence of live birth—as opposed to egg laying—is extremely rare and has only been found in a few fossils of dolphin-like reptiles called ichthyosaurs and marine lizards known as mosasaurs, Long said.
The new fossil captures a long-extinct placoderm, a primitive, shark-like armored fish.
这块化石也是脊椎动物性别的最早记录，因为胎生发生在卵细胞与雄性生殖细胞已经在体内融合之后。
“一种如此原始的鱼类却拥有这么进化的繁殖方式实在令人惊叹。”Long说。
有关胎生——与卵生相对——的化石证据极其稀少，只在形似海豚的爬行类ichthyosaurs和海生蜥蜴如mosasaurs中发现少数化石。
(Related: "Shark Ate Amphibian Ate Fish: First ‘Food-Chain Fossil’" [November 8, 2007].)
Dinosaurs of the Sea 海里的恐龙
Often called the "dinosaurs of the sea," placoderms were the ruling class of marine creatures for 70 million years—in the middle of the Paleozoic period—until their extinction about 360 million years ago.
Paleontologists believe they are the most primitive jawed vertebrates, even predating sharks.
(Related: "Fossil Meat Found in 380-Million-Year-Old Fish" [February 12, 2007].)
The newfound mother fish measures 10 inches (25 centimeters) long, but other placoderms can grow to 20 feet (6 meters)—"some gargantuan in size," Long said.
Much of the fish’s soft tissue has been preserved in a three-dimensional state, making the fossil "basically an exact replica of the living animal," said study co-author Kate Trinajstic, a paleontologist at the University of Western Australia.
(Read about a dinosaur fossil found with intact skin in China.)
经常被称作“海里的恐龙”的盾皮鱼在古生代统治着海洋长达7千万年，直到3.60亿年前灭绝。
古生物学家们认为它们是最原始的有颌脊椎动物，甚至捕食鲨鱼。
新发现的这条母鱼有10英寸（25厘米）长，但其他的placoderms可以长到20英尺（6米）——“相当庞大的体型”Long说。
鱼的大部分软组织处在立体的保存状态，使化石“基本上是一个准确的活体动物的复制品”，研究的共同作者Kate Trinajstic说。她是西澳大利亚大学的一位古生物学家。
"The material was so well preserved that we were able to pick up subtle details," Trinajstic said.
Such details helped the scientists determine that the prehistoric mother and baby are a new species of ptyctodont, a type of placoderm that has plates around the head and neck rather than the extensive body armor of its relatives.
They named the species Materpiscis attenboroughi—a combination of "mother fish" and a nod to world-renowned naturalist Sir David Attenborough.
Attenborough’s 1979 TV series Life on Earth first brought to light the scientific value of the Gogo area in the Kimberley region of Western Australia.
The area is the site of an ancient barrier reef that once teemed with marine life.
Fossils in the Gogo are so immaculately preserved because the reef became devoid of oxygen, which quickly killed the fish and the scavengers that would otherwise devour them, Trinajstic said.
Rapid burial and a stable tectonic continent made for near-perfect fossil preservation conditions.
A description of the fossil is published in this week’s issue of the journal Nature.
“材料保存的如此完好，使我们能够观察很微妙的细节”，Trinajstic说。
这些细节帮助科学家们确定这个史前妈妈和她的孩子属于一个新的物种ptyctodont，placoderm的一类，具有环绕头部和颈部的盾片而非像它们的亲戚那样是大片的体甲。
他们将这个物种命名为Materpiscis attenboroughi，结合了“mother fish”和向享有世界声誉的自然学家David Attenborough爵士致敬的意义。
1979年，Attenborough的系列电视片“地球上的生命”第一次向世人展示了西澳大利亚Kimberley区Gogo地区的科学价值。
Trinajstic说，Gogo的化石能够保存地如此完好的原因在于礁石上氧气的缺乏，使鱼很快死亡并避免了食腐动物的吞噬。
快速的掩埋和稳定的地形构造条件形成了完美的化石保存条件。
关于化石的一篇描述将刊登在本周的Nature上。
Evolutionary Innovation 进化革命
Michael Lee, an evolutionary biologist at the South Australian Museum, was not involved in the new research.
"Live-bearing and maternal nourishment of embryos is a very important evolutionary innovation, which we ourselves exhibit," Lee said.
"The evidence that the included individual is an embryo [rather than ingested prey] is very strong—it’s the same species, the right size to be an embryo, in the correct location within the body, and has what appear to be umbilical structures."
Live birth "might be preserved more commonly than we thought. Now that we know what to look for, it might be noticed more often," he added.
In fact, a reevaluation of a fossil found in 1986 reveals that it is a second placoderm fossil with three embryos nestled inside the mother. Study author Long had found the second specimen, a Gogonasus fossil, on an expedition to Gogo funded by a National Geographic Society grant. (National Geographic News is part of the National Geographic Society).
At the time, Long thought the embyros were scales.
(Related: "Ancient Fish Fossil May Rewrite Story of Animal Evolution" [October 18, 2006].)
"There are still lots of things to discover," Long said. "Gogo is giving us a picture not just of reproduction, but of the whole lifestyle of these creatures."
Michael Lee，来自南澳大利亚博物馆的进化生物学家，并没有参与这次研究。
“胎生以及母亲对胎儿的抚养是一个重要的进化变革，我们自身已经展示了这一点，”Lee说，
“包含在体内的个体是一个胚胎而非吞食物的证据非常明显——它们是同一物种，作为一个胚胎的合适大小，在体内恰当的位置，
还有一个脐带外观的结构。”
胎生“或许比我们想象的更加普遍。现在我们知道该寻找什么了，这种现象应该被更多地关注。”他补充道。
事实上，在对1986年发现的一块化石的重新鉴定中发现，这是第二块拥有三个胚胎依偎在母亲体内的p盾皮鱼石。研究作者Long已经在一次由国家地理协会基金资助的对Gogo地区的考察中发现了第二个标本，Gogonasus。
那个时候，Long还以为那些不是胚胎，而是鱼鳞。
“还有很多东西等待我们去发现，”Long说，“Gogo不仅向我们展示了这些生物的繁殖图景，还有它们的整个的生存方式。”
A remarkably well-preserved fossil dating from between 375 to 380 million years ago shows an embryo connected to a mother by an umbilical cord, as seen in an artist’s rendering (above).
The fossil (bottom), was found in the Australian outback and is the earliest evidence of a vertebrate mother giving birth to live young—shifting back the date some 200 million years, a new study found.
Images courtesy Museum Victoria
0NG news: Tasmanian Devils Named Endangered Species
Tasmanian Devils Named Endangered Species
Dave Hansford in Wellington, New Zealand
for National Geographic News
May 21, 2008
http://news.nationalgeographic.com/news/2008/05/080521-endangered-devils.html
被称为塔斯马尼亚魔鬼的濒危物种
The Tasmanian devil, a feisty marsupial that lives only in the Australian island state of Tasmania, was deemed an endangered species this week by the state’s government.
The government had previously classified the creature as vulnerable. But its more critical status comes in response to a fatal epidemic of devil facial tumor disease, which has wiped out large numbers of the animal.
Devil numbers are difficult to estimate, but state government figures suggest the animals may have plummeted from around 150,000 in the mid-1990s to between 20,000 and 50,000 by the end of 2006.
"The change in the devil’s status reflects the real possibility that this iconic species could face extinction in the wild within 20 years," Tasmania’s Primary Industries Minister David Llewellyn said in a statement.
塔斯马尼亚魔鬼（袋獾），一种只生活在澳大利亚塔斯马尼亚州的活泼的有袋类动物，本周被当地政府列为濒危物种。
之前州政府将这种动物划为易危物种，但一种致命的面部肿瘤疾病在袋獾中开始流行，使其数目大幅下降。袋獾的生存状况变得严峻。
袋獾的数目很难估计，但州政府的数字显示其数量可能已经从上世纪90年代中期的150，000大幅下降到2006年末的20，000到50，000。
“袋獾数量的变化意味着这种标志性的物种可能在20年内从野外消失”，塔斯马尼亚首席工业部长David Llewellyn在一次发言中说。
(Read: "Tasmanian Devils Decimated by Mystery Cancer" [March 29, 2005].)
Unusual Cancer
The devils’ disease is one of just two known cancers able to spread like a contagious disease, and is transmitted when one devil bites another.
Large tumors form on the faces and necks of the animals, making it impossible for them to eat. Many of the afflicted animals subsequently die of starvation.
Sightings of devils have dropped by 64 percent in the past decade, according to Warwick Brennan, spokesperson for the Save the Tasmanian Devil Program, a joint effort of the state government and the University of Tasmania.
"It’s a stark warning about how suddenly and dramatically things can change," he said.
The disease has now spread across more than 60 percent of the state, and in the northeast—where it was first detected in 1996—there have been no signs of recovery, he added.
"Usually a disease will peter out in time, but we’re just not seeing that."
No one knows the cause of the disease, though some experts have suggested flame retardants found in some devils may make them more susceptible to cancer.
不寻常的癌症
袋獾所患的疾病是两种已知的能够像传染病一样传播的癌症中的一种，可以通过动物间的厮咬感染。
大块的肿瘤在袋獾的脸和脖子上生成，使它们不能进食，许多动物因此被饿死。
据拯救塔斯马尼亚恶魔项目的发言人Warwick Brennan介绍，袋獾的目击报告在过去十年里少了64%。这个项目是州政府与塔斯马尼亚大学共同努力的结果。
“这是一个关于事情怎么突然而显著地变化的残酷警告。”他说。
这种疾病现在已经扩散到全州60%的地方，在东北部——1996年第一次检测到该病的地方——则已经没有了恢复的迹象，他补充道。
“通常一种疾病会随着时间慢慢耗尽，但在这里我们还没有看到。”
尽管有些专家说在一些袋獾体内发现的阻燃剂可能使它们更容易得癌症，但目前还是没有人知道这种疾病发生的确切原因。
Ecological Impact
Ray Nias heads WWF-Australia’s conservation program.
He said Tasmanian wildlife would suffer if the devil disappeared, because it has prevented alien predators—such as foxes and feral cats—from exploding in number.
(Related: "Foxes Invade Tasmania, Create ‘Environmental Emergency’" [August 22, 2006].)
"Tasmania is an ark for Australia," Nias said. "Its mammal fauna is still largely intact.
"If the devils go, and the foxes and cats increase, it would be all over for a good dozen or more species of mammals—many of which are unique to Tasmania … not to mention lizards and ground-dwelling birds."
生态压力
Ray Nias领导着世界自然基金会-澳大利亚保护项目。
他说塔斯马尼亚的野生动物将因为袋獾的消失而陷入困境，因为袋獾能够防止外来的掠食者——例如狐狸还有凶猛的猫——的数量激增。
“塔斯马尼亚就如同澳大利亚的诺亚方舟，” Nias说，“它的动物群落大部分还是完好无损的。”
“如果袋獾消失了，狐狸和猫就会增加，而这将会是十几种甚至更多的哺乳动物的末日——而且大多是塔斯马尼亚独有的物种……更不用提蜥蜴和在陆地生活的鸟类了。”
Last Bastion
Conservationists are pinning their hopes on a small wild population of the marsupials in Tasmania’s northwest, where the disease has yet to take hold.
"There remains a suggestion that perhaps that population has some immunity," the Save the Tasmanian Devil Program’s Brennan said.
Already, some healthy devils have been captured and sent to facilities on mainland Australia to form the nucleus of a captive-breeding population.
"We’re hoping that this [endangered listing] will lead to wider recognition of just how serious the threat remains … and bring further assistance in," Brennan said.
最后的堡垒
保护者们将希望寄托在塔斯马尼亚西北部的一个小的野生种群上，在那里疾病尚未站稳脚跟。
“存在着一种可能性是这个种群已经有了一些免疫能力，”拯救塔斯马尼亚恶魔项目的Brennan说。
事实上，一些健康的袋獾已经被捕捉并送到澳大利亚中部的机构，作为一个捕捉-抚育种群的核心。
“我们希望这个‘濒危名单’能够使更多人意识到存在的威胁有多大，并给保户事业带来更多的帮助。” Brennan说。
