This course is about life in the oceans, from the sunlit surface to the inky depths, from microscopic phytoplankton to the great blue whale. The ocean is among the world’s most inhospitable environments for scientific research, which is why we know as much about the surface of the moon as we do the bottom of the sea. This course uncovers the evolutionary history of marine organisms, adaptations to life in water, the behavior and functional morphology of sea animals, interactions between species, and current threats. Throughout the course, we meet scientists who are developing ingenious solutions for overcoming challenges and are making remarkable discoveries. By evaluating these cases and analyzing real scientific data, we come to understand some of the ways that life has adapted to diverse ocean habitats, how it interacts with the physical environment and with other organisms, and why it matters to us.