ABSTRACT
Research in evolutionary ecology has changed through time. Some researchers have taken a very empirical view, simply trying to describe patterns in nature. Other researchers have tried to develop general theories that can then be applied to predict patterns in a range of species. Three examples that illustrate that dichotomy are the evolution of live-bearing (viviparity) from egg-laying (oviparity) in reptiles, the evolution of sex-based differences in body size in snakes, and the way in which patterns of reproductive output by females are shaped by the “costs” of pregnancy. Studies on Australian snakes and lizards have clarified all of these questions. To understand the evolutionary forces that favor large body size in males, the author implanted radio transmitters in Red-Bellied Blacksnakes and followed them in the field to record interactions with other male and female snakes.
