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