Introduction - Antarctic ecology in a changing world

Antarctica offers an unrivalled natural laboratory for fundamental research on the evolutionary processes that shape biological diversity on both local and regional scales. Physiologists and ecologists have long been attracted to environments that lie at the limits of the physical conditions capable of supporting life. This is because the polar regions, the deep-sea, hot springs or hydrothermal vents demand striking adaptations at the molecular, cellular or whole-organism level to allow organisms living there to survive, grow and reproduce. Early work on these systems tended to concentrate on specific adaptations, such as membrane function in high-temperature microbes, or antifreeze proteins in polar fish. These specific adaptations are aspects of environmental adaptation in general (Clarke, 1983, 1991; Hochachka & Somero, 2002), and hence the comparative approach has contributed to our overall understanding of evolutionary adaptation at the molecular level. In addition the recent revolution in molecular techniques, particularly those in transcriptomics and proteomics over the past decade, has allowed us to link the genome to the environment in entirely new ways (Feder & Mitchell-Olds, 2003; Chen et al., 2008). For example it is now possible to couple data on protein structure and gene expression to ecosystemlevel processes, and thereby to the evolution of entire communities (Whitham et al., 2006). This brings with it the implicit recognition that these links operate over a range of scales of both time and space.