Extinctive evolution: Extinctive and competitive evolution combine into a unified model of evolution

Individual extinctions of abundant and widespread species of marine Protista are abrupt and precede the appearance of new species. New species evolve gradually in marginal marine environments and spread only if a suitable ecological domain is available or if such a domain is made available by the disappearance of its occupant species. Competitive evolution, with its classic processes of genetic drift, adaptation, competition, and survival of the fittest, occurs mainly in marginal environments (and possibly within broadly distributed but rare species). Extinctive evolution, on the other hand, with its processes of sudden extinctions and sudden appearances, absence of competition, absence of “missing links”, and frequent survival of the misfit or the indifferently fit is prevalent in broader environments, and more generally applicable to the paleontological record. The modern biosphere is not necessarily better adapted than its predecessors. Global mass extinction affecting different taxa across a broad spectrum of environments is caused by extraordinary environmental disturbances. A major ecosphere is vacated, which is immediately occupied by surviving misfits. These are replaced, through competitive evolution, by a rapid succession of increasingly better adapted species that can be classified into different genera and higher taxa (“macroevolution”). Equilibrium is largely re-established within a few million years. Competitive and extinctive evolution combine into a unified model of evolution.