Now that much more is known about the effects of UV radiation at the organism level, we are gaining an understanding of how this impacts ecosystems as a whole. From microbial to plant ecosystems, this book examines how changes in UV radiation, caused by ozone depletion, as well as by changes in radiation levels throughout the evolution of life on Earth, can alter species composition and interspecies competitiveness. Two foci of the book are the evolutionary aspects of the effects of UV and the various synergistic interactions of UV radiation with other environmental factors.