A hypothesis for how herbivores and pathogens affect levels of this quantity in forests was proposed by Janzen and Connell. A measure of this quantity is given by [read slowly] “one minus the sum of little n times little n minus one, over big N times big N minus one.” Measures for this quantity named for Simpson (10[1])and Shannon consider both evenness and richness. A “latitudinal gradient” describes how this biological quantity increases near (10[1]-5[1])the (10[1])tropics. Regions with high values for this quantity that are threatened by human habitation are known as its “hotspots” and include the Amazon Rainforest. For 10 points, name this quantity that measures the variability of species in a (10[1])region. ■END■