Speciation does not necessarily promote evolutionary change; rather, speciation 'gathers in' and guards evolutionary change by locking and stabilization for sufficient geological time within a Darwinian individual of the appropriate scale. If a change in a local population does not gain such protection, it becomes-to borrow Dawkins's metaphor at a macroevolutionary scale-a transient duststorm in the desert of time, a passing cloud without borders, integrity, or even the capacity to act as a unit of selection, in the panorama of life's phylogeny.
Stephen Jay GouldBut we all recognise the primary foible of frail humanity - our propensity for embracing hope and shunning logic, our tendency to believe what we desire rather than what we observe.
Stephen Jay GouldThe history of life is more adequately represented by a picture of 'punctuated equilibria' than by the notion of phyletic gradualism. The history of evolution is not one of stately unfolding, but a story of homeostatic equilibria, disturbed only 'rarely' (i.e. rather often in the fullness of time) by rapid and episodic events of speciation.
Stephen Jay Gould