Vision in Frogs and Toads

Organisms rely on their senses - touch, hearing, vision, smell - to interpret their surroundings for foraging, avoiding predators, finding mates, regulating temperatures, and following their circadian rhythms. In this book, we focus on vision, and in particular, how the vertebrate eye processes light to form images. We designed this book to be introductory, visual, and interactive, suitable for an audience with basic knowledge in biology (middle school and up), with a few more advanced topics for those of you who are interested in diving into the nitty gritty of vision. Throughout this book we highlight how animals across the Tree of Life evolved incredible solutions to the visual challenges of their environments.

You will notice that there are a lot of frogs in this book. Frogs are amazing animals because they have adapted to live in a wide variety of environments, from tropical rainforests to deserts, underground (fossorial) to tree-dwelling (arboreal). While some species are active during the day, others come out at night. Some frogs are completely aquatic and of course, many frogs have a major transition in their development as they metamorphose from an aquatic tadpole to an adult (but as you’ll learn, some frogs do not!) All of these factors influence how a frog perceives its environment, and vision plays an important role. Because frogs have evolved to live in diverse habitats, they are an exciting group to study how the eyes have responded to different environmental visual pressures. In this book we use frogs as the guiding example to illustrate the structure, function, and evolution of the vertebrate eye and the tools researchers use to study this diversity and how it evolved.