11 research outputs found
Local phylogenetic divergence and global evolutionary convergence of skull function in reef fishes of the family Labridae
The Labridae is one of the most structurally and functionally diversified fish families on coral and rocky reefs around the world, providing a compelling system for examination of evolutionary patterns of functional change. Labrid fishes have evolved a diverse array of skull forms for feeding on prey ranging from molluscs, crustaceans, plankton, detritus, algae, coral and other fishes. The species richness and diversity of feeding ecology in the Labridae make this group a marine analogue to the cichlid fishes. Despite the importance of labrids to coastal reef ecology, we lack evolutionary analysis of feeding biomechanics among labrids. Here, we combine a molecular phylogeny of the Labridae with the biomechanics of skull function to reveal a broad pattern of repeated convergence in labrid feeding systems. Mechanically fast jaw systems have evolved independently at least 14 times from ancestors with forceful jaws. A repeated phylogenetic pattern of functional divergence in local regions of the labrid tree produces an emergent family-wide pattern of global convergence in jaw function. Divergence of close relatives, convergence among higher clades and several unusual âbreakthroughsâ in skull function characterize the evolution of functional complexity in one of the most diverse groups of reef fishes
POWER, INFLUENCE, AND HIERARCHY: DEFENSE INDUSTRIES IN A UNIPOLAR WORLD
The global defense-industrial sector reflects the hierarchy of power in the post-Cold War world. As in the larger international system, the United States plays the dominant role in the defense sector as well. It is a comparative advantage often used by US policymakers to influence the foreign policy behavior of other states. Curiously, the radical concentration of the world's defense industrial sector, as described here, has received relatively little scrutiny from either academia or the media, even though it not only reflects the international order but provides the United States with considerable leverage in it.International Relations, Defense industries, Arms industries, Power, Influence, Unipolar, Globalization, Arms transfers, Arms exports,