"According to Woese's evolutionary tree, the most primary of the present-day bacteria lie within a group called the archaebacteria. All archaebacteria thrive in intense heat... Woese believes that that these modern species evolved from a similar type of ancient bacteria that... may have drawn its energy from the sulfurous compounds spewing out of hydrothermal vents. If that's true, the bacteria seen at vents today could be the closest descendents we know of the original forms of life on earth."