Identity and novelty in the avian syrinx.

摘要: In its most basic conception, a novelty is simply something new. However, when many previously proposed evolutionary novelties have been illuminated by genetic, developmental, and fossil data, they refined narrowed our concept of biological “newness.” For example, show that these can occur at one or multiple levels organization. Here, we review the identity structures in avian vocal organ, syrinx, bring together developmental data on airway patterning, structural from across tetrapods, mathematical modeling to assess what novel. contrast with laryngeal cartilages support folds other vertebrates, find no evidence individual cartilage rings anchoring syrinx homology any specific elements outgroups. Further, unlike all vertebrate organs, not derived known valve precursor, origin involves transition an “spandrel” respiratory tract, site where trachea meets bronchi, target for novel selective regimes. We falls into unusual category structures: those having significant functional overlap replace. The along sensory signaling modalities, may more commonly involve changes contribute modify existing function rather than enable new functions.