共查询到20条相似文献,搜索用时 15 毫秒
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Holden C 《Science (New York, N.Y.)》1977,196(4297):1426-1428
To condense the evolution of life on Earth . . . suppose the whole history of the planet is contained within a single year. The conditions suitable for life do not develop until late June. The oldest known fossils are living creatures around mid-October, and life is abundant . . . by the end of that month. In mid-December, dinosaurs and other reptiles dominate the scene. Mammals . . . appear in large numbers only a little before Christmas. On New Year's Eve, at about five minutes to midnight, man emerges. . . . The period since 1600 A.D., when man-induced extinction began to increase rapidly, amounts to three seconds, and the quarter century just begun, when the disappearance of species may be on the scale of all the mass extinctions of the past put together, will take another sixth of a second-a twinkling of an eye in evolutionary time. 相似文献
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Endangered species. Cloned gaur a short-lived success 总被引:1,自引:0,他引:1
Vogel G 《Science (New York, N.Y.)》2001,291(5503):409
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Service RF 《Science (New York, N.Y.)》2001,291(5508):1470-1471
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Morell V 《Science (New York, N.Y.)》2007,316(5832):1678-1679
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Stokstad E 《Science (New York, N.Y.)》2002,295(5553):250-251
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Vogel G 《Science (New York, N.Y.)》2000,289(5483):1271-1273
Fourteen years ago, Congress declared the Southern California coast an otter-free zone--but the unwitting creatures aren't cooperating. That's no surprise to federal biologists, who this summer issued a report concluding that the otter-free zone harms the already-endangered population. Federal officials are now trying to come up with a better plan, but it's likely to draw from politics as well as science. 相似文献
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