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 (10[1])little n minus one, over (-5[1])big N times big N minus one.” Measures for this quantity named for Simpson (10[1])and (10[1])Shannon consider both evenness (10[2]-5[1])and richness. (10[1])A “latitudinal gradient” describes how this (10[1])biological quantity increases near (10[1])the tropics. Regions with high values for this quantity that are threatened by human habitation are known as its “hotspots” and (10[1])include the Amazon Rainforest. For 10 points, name this quantity that measures the variability of species in a region. ■END■