A simple cartoon shows the ‘envelope’ that includes all activities and items that involve biology. The left hand axis shows the size of the players, which range from a million-millionth of a millimetre to 20,000 kms and beyond. Along the base is the duration of biological processes. The briefest is the response of chlorophyll to impact by a photon (less than a femtosecond or one thousandth of a thousandth of a thousandth of a thousandth of a thousandth of a second) to the whole of the evolutionary process for organisms that started about 3 billion years ago. Both axes are divided into ten-fold steps for simplicity. The green zone is that part of the envelope that includes biological processes.