Paleontological Context for the Developmental Mechanisms of Evolution

The emerging field of evolutionary developmental biology (evo‐devo) seeks to identify the specific genetic basis for plant evolution. Whereas molecular biological studies are rapidly exposing the developmental mechanisms of evolution, paleontological studies reveal the sequence in which evolutionary changes have occurred. Aspects of both fields are reviewed in this article. Plant structure develops along genetically patterned pathways, some of which produce distinctive morphological features. Such features serve as “fingerprints” for regulatory mechanisms, thus providing a record of growth regulation for both living species and plant fossils. Transformational series of structure through geological time form the contextual framework for inferring evolution from the fossil record, but the most widely practiced application of transformational series for plants, Telome Theory, has no developmental basis. By contrast, the fossil record of leaf evolution in seed plants documents morphological changes to which a...