 His iconic diagram of the numbers of marine families from the Cambrian to the Recent illustrates the successive expansion and dwindling of three "evolutionary faunas" that were characterized by differences in origination rates and carrying capacities.The macroevolutionary relevance of environmental changes is most obvious in the case of global mass extinction events.Such events are usually due to massive disturbances of the non-biotic environment that occur too fast for a microevolutionary response through adaptive change.