The scale independence of evolution

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Abstract
SUMMARY In this paper, I argue that the ultimate causes of morphological, and hence developmental, evolution are scale independent. In other words, micro‐ and macroevolutionary patterns show fundamental similarities and therefore are most simply explained as being caused by the same kinds of evolutionary forces. I begin by examining the evolution of single lineages and argue that dynamics of adaptive evolution are the same for bacteria in test‐tube evolution experiments and fossil lineages. Similarly, I argue that the essential features of adaptive radiations large and small can be attributed to conventional forces such as mutation and diversifying natural selection due to competition. I then address recent claims that the molecular features of metazoan development are the result of clade‐level selection for evolvability, and suggest that these features can be more easily explained by conventional individual‐level selection for the suppression of deleterious pleiotropic effects. Finally, I ask what must be known if we are to understand the ultimate causes of molecular and developmental diversity.