QUITO, Ecuador (Reuters) - A volcano spewed ash and lava onto part of the ecologically delicate Galapagos Islands on Friday, threatening to kill vegetation and some animals on the island of Fernandina, officials said. The islands, of the coast of Ecuador, are considered one of the most important natural preserves in the world. "Evidently a lot of vegetation will be burned and some animals, especially iguanas, will die," Galapagos National Park Director Washington Tapia told Reuters. "But considering that Fernandina is the most pristine island of the archipelago, we don't have to worry much. This is a natural process," he said. No humans live on Fernandina, the westernmost island in the formation. The volcano, also called Fernandina, shot a column of ash and gas 7 kilometers (4.3 miles) into the air while lava descended its banks. The lava could reach the Pacific Ocean in five days, Tapia said. Sea lions, penguins and bullfinches also live on Fernandina.