Boundaries and thresholds

Three shorts on: widening the definition of life; finding what may be the first biological clock; and locating what may be one of its outer edges:

• One may define life, to the extent that the question makes sense, as a 'far-from-equilibrium dissipative system,' says Charley Lineweaver;
• An enzyme called peroxiredoxin (PRX) has acted as a biological clock in all organisms since about 2.5 billion years ago;
• 86 million year old mud 30 metres below the sea floor contains archaea that take hundreds to thousands of years to go through one division.