Divergent & Convergent Evolution

On ERV, Abbie Smith reports that scientists have discovered an entirely new branch of viruses in the boiling acid pools of Yellowstone National Park. By analyzing RNA segments from the pools, researchers inferred the existence of positive-strand RNA viruses with unknown genetic configurations. Smith writes, “These viruses are not just kinda new. They are really really different from the RNA viruses we already know about!” They infect primordial single-celled organisms called Archaea which thrive in the extreme heat of the pools. On the multicellular side of life, Dr. Dolittle shares the first pictures of “a new family of limbless caecilian amphibians” from India. Although they look like worms, “genetic testing and comparative analyses of their cranial anatomy show that they are in fact an ancient lineage of amphibians that first appeared ~140 million years ago.”  This seems like a clear example of convergent evolution--does living in the dirt lead one to look like an earthworm?  Or do these caecilians gain some advantage through resemblance?

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