March 20, 2009 -- The Amazon basin is well known for its wide variety of species, but the rainforest might owe some credit to the mountains as a source for that rich diversity. A new study found that populations of poison frogs made their way from the Andes to the Amazon about a dozen times over the last 10 million years. Scientists suspect that the mountains have long been supplying the jungle with other species of plants and animals, too. Besides weighting a long-standing debate about the source of biodiversity in the Amazon, the new work suggests a need to rethink the way we go about protecting the region. "The history of what's in the Amazon is complex and coupled to the evolutionary history of the same groups in other regions," said evolutionary biologist David Cannatella, of the University of Texas, Austin. "What that means is that if you want to understand what you need to do to protect the Amazon," he said, "You need to understand what's going on in the Andes." Related Content:
Led by his graduate student Juan Santos, Cannatella and colleagues chose to study poison frogs as a test case of Amazonian biodiversity because they are diverse and widespread. Some 350 species of poison frogs live throughout Central America, from Andean highlands to lowland rainforests. About 70 species live in the Amazon itself. The team used DNA analyses and new modeling techniques to figure out exactly when each of more than 200 species branched off from an ancestral family tree, and where each ancestor lived when the branching happened. The genealogy stretched back more than 25 million years. Published in the journal PLoS Biology, the tree showed a series of pulses, most in the last 10 million years, from the Andes to the Amazon. With each wave of immigration, frogs split into new species in the highlands before dispersing to the lowlands, where they evolved further. Get More NewsSpiders, Scorpions Among World's Oldest CreaturesMany creepy crawlies have been on Earth much longer than previously believed.Blood-Sucking Vampire Bats Sing DuetsWhite-winged vampire bats "harmonize" with separated roost mates.Oldest Hebrew Writing Possibly FoundAncient inscriptions on a 3,000-year-old pottery shard could make history.Rare, Prehistoric-Age Reptile Found in N.Z.A tuatara has been spotted on the New Zealand mainland for the first time in 200 years.Iceman Has No Living RelativesOetzi, the 5,300 year-old frozen mummy, left no living genetic legacy.SLIDE SHOW: Landscapes of TerrorWhat makes a place feel scary? There are scientific explanations.It's Official: People Are Warming the PolesHumans are conclusively to blame for polar warming, say scientists.Eight-Armed Animal Preceded DinosaursWhat may be one of Earth's first animals was no bigger than a coaster and had eight arms.Phoenicians Live on in People's GenesOne in 17 Mediterranean men may be descended from ancient Phoenicians.Pesticides, Fertilizers Linked to Frog DeclineA pesticide is found to promote parasites among amphibians.Hubble Telescope Taking Photos AgainThe Hubble Space Telescope is once again snapping stunning photos of the universe.Andean Mummy Hairs Show Hallucinogen UseScientists find direct evidence of hallucinogenic drug use among ancient Andeans.Opals on Mars Reveal Planet's Long Wet PastOpals found on Mars suggest the planet has been wet for much longer. |
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