chapter eight The In! uence of Flight on Patterns of Body Size Diversity and Heritability

The ability to * y confers suf+ cient selective bene+ ts that over evolu-tionary time three different vertebrate groups have independently evolved powered * ight. Of these three—the Pterosauria (pterosaurs), Chiroptera (bats), and Aves (birds)—the latter have unquestionably been the most successful, diversifying into an enormous range and number of species. Current taxonomy places the number of recognized bird species at over 10,000 (Clements 2007). Although Chiroptera also evolved pow-ered * ight and are relatively speciose (∼1,100 recognized species; Wil-son and Reeder 1993), they occupy a much narrower range of the body mass spectrum and are not nearly as ecologically diverse (Fenton 2001; Maurer et al. 2004). Most Chiroptera, for example, are either frugivo-rous (e.g., Megachiroptera), or insectivorous, and all are nocturnal. In contrast, birds occupy virtually all trophic levels from scavengers (e.g., buzzards, vultures) to top predators (e.g., falcons, hawks, and their al-lies) and have evolved enormous diversity in both size and shape. The development of powered * ight brought with it a common set o