Researchers have identified 1.4 million animal species so far—and millions remain to be discovered, named, and scientifically described. So how much would it actually cost to 1every animal on Earth? A pair of Brazilian scientists has crunched(详细计算)the numbers and 2up with an answer: $ 263 billion. That's way more than the $ 5 billion that famed Harvard University biologist Edward O. Wilson estimated back in 2000—and that was for every species on Earth, not just animals. But even $ 263 billion would be a 3price to pay to understand the creatures that 4such essentials as agriculture, fisheries, new drugs, and energy sources, says ornithologist(鸟类专家)Joel Cracraft of the American Museum of Natural History in New York City. "Literally, the world economy runs on biodiversity," he says. "People don't understand really, deeply how much we depend on biodiversity." Most biologists agree that with extinction rates 5and climate change looming, the 6to document the planet's biodiversity—or biota(生物区)—is urgent, 7considering the essential role these life forms play in crop pollination, clean air, and other aspects of human 8"We are losing species by extinction faster than we are describing new species" according to some estimates, says biologist Antonio Marques, who 9the new paper with Fernando Carbayo, both at the University of St. Paulo in Brazil. "We have to know the biota to preserve and conserve the biota," he says. Besides the money, another huge 10to a complete understanding of the animal kingdom is a global shortage of taxonomists(分类学家), experts say. A)attempt F)effort K)obstacle B)cheaper G)enable L)small C)classify H)especially M)soaring D)coauthored I)exactly N)well-being E)come J)identify O)yet