Meeting Abstract

14.1  Wednesday, Jan. 4  Pecking at the Origin of Morphological Diversity: Insights from Darwin’s Finches and Other Birds ABZHANOV, A; Harvard University, Cambridge

The faces of vertebrates display a number of species-specific and adaptive characteristics, which they acquired during evolution by natural selection. The classic textbook example of adaptive radiation, natural selection and niche partitioning in animals is the fifteen closely related species of Darwin’s finches (Thraupidae, Passeriformes), whose primary diversity is in the size and shape of their beaks. This natural morphological diversity is associated with the exploitation of various ecological resources and its developmental basis is not fully understood. It is likely that this stunning diversity of beaks in Darwin’s finches and cranial morphology in vertebrates more generally was produced by alterations in their craniofacial developmental genetics. We continue to discover high degree of modularity in the developing finch beaks. For example, we recently discovered that two distinct regulatory and tissue modules regulate beak shapes. Such levels of modularity help to explain the levels of morphological variation observed in Darwin’s finches. Moreover, we began analyzing beak shapes using mathematical approaches followed by developmental studies in both Darwin’s finches as well as other groups of songbirds. These studies allow us better understand developmental mechanisms for morphological evolution in animals. Finally, we are using a combination of morphometrics, comparative and functional approaches to study evolution of the avian-specific cranial features during their evolution from more basal archosaurs and theropod dinosaurs. Our analyses reveal novel patterns and mechanisms of the origin and diversification of avians on both micro- and macro-evolutionary levels.