One unique species, the lava cactus (Brachycereus nesioticus), is found only on the Galapagos Islands. This cactus colonises dried lava flows, providing the foundation for an entire ecosystem.

QUITO, Ecuador — A volcano on an uninhabited island in the Galapagos has begun erupting, lighting up the nighttime sky as lava tumbled down its sides toward the sea. The La Cumbre volcano on ...