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 (10[1])named for Simpson and (10[2])Shannon (-5[1])consider (10[1])both evenness (10[1])and richness. (10[2])A “latitudinal gradient” describes how this biological quantity increases near the tropics. Regions with high values for this quantity that (10[1])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■