Testing the roles of ecological traits and key innovations in diversification

Seminar with Dr. Lauren Sallan
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Please note: this seminar will take place at 1PM on TUESDAY March 2nd

Determining the drivers of divergence is at the core of evolutionary biology; how these scale up to diversification is at the core of macroevolution. A full picture of both processes requires information from multiple areas of organismal biology (e.g. development, biomechanics, phylogenetics) and ecology (e.g. community dynamics, environmental factors), preferably at multiple scales (e.g. spatial, temporal, molecular and taxonomic). Fishes can provide essential data on all these aspects; their 34,000 living species include everything from keystone taxa like parrotfishes to classic radiations like cichlids to developmental model systems like zebrafish, while their abundant fossil record stretches back 450 million years. Here, I cover how the synthesis of “Big Data” and organismal-level investigations of fishes, living and extinct, is changing views of both divergence and diversification in animals. First, I show how quantitative analyses of species-rich fish clades have revealed unexpected roles for diet, habitat choice, and even life histories in determining the fate of nascent radiations. Next, I show how supposedly-novel “key innovations” deemed central to the origins of major clades, such as spinal changes in tetrapods, evolved repeatedly from pre-existing developmental modules and under common functional demands, with mixed results. These discoveries contribute to a new understanding of the factors determinative of diversification, but also suggest some definitions of macroevolutionary “success” are in need of revision.