Convergent Evolution in Poison Frogs
By Bjorn Carey
LiveScience Staff Writer
posted: 08 August 2005
05:22 pm ET
Scientists have discovered one of the most intricate examples of convergent evolution with the help of South American "poison" frogs and ants and their cousins in Madagascar. (And here’s an odd fact for smokers: one Madagascan frog studied was found to have nicotine in its system!)
Poison frogs can’t make their own poison—they steal it from ants. Poison frogs secrete a variety of chemicals called alkaloids to create a poisonous defense against predators. Since they can’t produce alkaloids on their own, these frogs maintain a steady diet of specific alkaloid-rich ants to keep up their defense.
Now, Valerie Clark of Cornell University and her colleagues have detailed two instances of convergent evolution—the process in which organisms not closely related independently acquire similar characteristics while evolving in separate ecosystems—between frogs and ants on two continents.
First, species of ants high in alkaloids had to evolve on two separate continents.
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http://www.livescience.com/animalworld/050808_poison_frogs.htmlInteresting article. Another notch in the belt of evolution and science...