||P.9 right column bottom paragraph: "The increasing abundance of game animals in grassland environments is evident in Table 4, which shows the levels of primary, secondary (herbivore) and tertiary (carnivore) productivity in modern day woodland and savanna ecosystems of the tropics. Whereas the overall level of primary productivity in the savanna is only about half that of the woodland, secondary productivity (the abundance of herbivores) is almost three times greater in the savanna. Consequently, the expansion of the savanna in Plio-Pleistocene Africa would have limited the amount and variety of edible plant foods for hominids, but also resulted in an increase in the relative abundance of grazing mammals such as antelope and gazelle. These changes in the relative abundance of different food resources offered an opportunity for hominids with sufficient capability to exploit the animal resources. The archeological record suggests that this is what occurred with H. erectus—the development of the first rudimentary hunting and gathering economy in which game animals became a significant part of the diet and resources were shared within foraging groups (Potts, 1988, Harris and Capaldo, 1993, Roche et al., 1999)."