An Evolutionary Model for the Neoproterozoic (Ediacaran)-Phanerozoic Biosphere <br/>Part Two—Exploitation of Terrestrial Environments

Adaptations introduced through the progressive development of the various phyla through geologic time are either directly or indirectly the result of their competition with each other. Evolutionary transformations of the archetype, or fundamental structure, including its systems and organs, from which a natural group of animals or plants are assumed to have evolved, is the product of long and directed selection that can span millions of years. Aromorphosis (one of the main trends in biological evolution characterized by increased organization without narrow specialization) has favored the groups with the most successful archetypes (original pattern or model for later related individuals and groups, e.g., bilaterally symmetrical groups and the vertebrates). Throughout the Phanerozoic, dominant groups suppress those less successfully developed groups by closing their pathways to progressive development.