Cyclism revisited: extinction and ‘Achilles’ Heels' keep diversification in check on macroevolutionary time scales

摘要: Mass extinctions of varying magnitude prune the continuous diversification predicted by Darwinian evolutionary processes. They are caused events that too rare to become adaptatively accommodated. Their effects depend not only on nature and triggering event but also state biosphere at particular time. This is most clearly shown existence Golden Ages preceding all Phanerozoic mass extinctions. These coincide with greenhouse periods, in which doomed clades gave rise heteromorphs, deviating strange ways from established bauplans. When critically examined, seemingly ‘decadent’ morphologies Schindewolf's ‘typolytic stages’ turn out have been highly functional. The paradoxical link between adaptive peaks failure can now be explained. Specialisation tends increase vulnerability (1) narrowing niches (2) retention clade-specific conservative features happen fatal Achilles’ Heels for entire cla...