concept

Maximum parsimony

The principle for choosing a family tree: among the countless trees one could draw, prefer the one requiring the fewest evolutionary steps to explain the observed traits. It is Occam's razor applied to life - the tree that needs the least coincidence, the fewest repeated novelties, wins, because it is the simplest hypothesis that fits the data. The method is powerful and intuitive, but it has an Achilles' heel: when lineages change at very unequal rates, it can break through long-branch attraction.