[Feature] A shortcut to a species
A hefty finch with an outsized head is the poster child for a recently recognized source of new species: hybridization. For decades biologists have explored how cross-species matings can accelerate evolution by introducing genetic novelty into the parent lineages. But they now realize that the hybrid offspring themselves can thrive and set off on their own evolutionary path. The bird was first noticed in 1981 and it and its descendants have kept to themselves for generations now, still singing the unusual song and breeding only among their own kind. They don't quite represent a new species yet, but between 4% and 10% of plant species appear to have arisen this way. And researchers are finding new examples among birds, insects, fish, and marine mammals. Author: Elizabeth Pennisi