Feb. 16, 2011 According to Dr Annette Baudisch of the Max Planck
Institute for Demographic Research in Rostock, Germany, current
methods of comparing patterns of ageing are limited because they
confound two different elements of ageing -- pace and shape.
"Some organisms live a short time, others live a long time. This
is the pace of ageing. Short-lived species have a fast pace of
ageing, and long-lived species have a slow pace of ageing. Pace
describes how quickly the clock of life ticks away. For humans
it ticks slowly, for small songbirds like the robin it ticks
very fast," explains Dr Baudisch. By contrast the shape of
ageing describes how much mortality -- the risk of dying --
changes with age. One way of measuring the shape of ageing is
the 'ageing factor'. For example, the common swift has an ageing
factor of 2, meaning mortality doubles during its adult life,
compared with modern humans, who have an ageing factor that
exceeds 2000. "At the age of 15, only 2 out of 100,000 girls in
Sweden die, but one o