“[Rising diversity and complexity are] the predicted outcome for evolution in the total absence of selection and other forces. They are the zero-force expectation. The reason is simply that variation arises in biological systems, and when heritable it accumulates, with the result that variances tend to increase. And both diversity and complexity are aspects of variance.” EvolutionDiversityComplexitySelectionEvolutionary BiologyVariance Book:Biology's First Law: The Tendency for Diversity and Complexity to Increase in Evolutionary Systems Source: Biology's First Law: The Tendency for Diversity and Complexity to Increase in Evolutionary Systems