Ellen Thomas, research professor of earth and environmental sciences, examines the fossils of sea creatures from her office in Exley Science Center. Thomas extracted her samples from the ocean's floor. She says they are more than 65 million years old. Posted 03/01/06 The largest habitat on Earth lies hundreds to thousands of feet beneath sea level, in a dark, near-freezing, high-pressure environment with little food. About 65 million years ago, the life forms living on the ocean-floor in this habitat survived the an asteroid impact, which probably wiped out the dinosaurs and many other forms of life on land and…