Sharp reductions in this quantity are referred to as "bottlenecks", and very large values of this quantity are a fundamental assumption for Hardy-Weinberg equilibrium.
This quantity is held constant in the stochastic Moran process. The rate of change in this quantity is given by the dominant eigenvalue in the Leslie matrix, and changes in this quantity are represented by the lambda term in the Euler-Lotka equation. The Chapman estimator for this quantity reduces the small-sample size bias encountered when estimating this quantity with the (*) Lincoln-Peterson method. That method for estimating this quantity frequently uses data obtained with the mark-recapture technique. Sharp reductions in this quantity are referred to as "bottlenecks", and very large values of this quantity are a fundamental assumption for Hardy-Weinberg equilibrium. For 10 points, name this variable describing the number of individuals from one species in a region. 
This quantity is held constant in the stochastic Moran process.
population size [accept either/both; do not accept "population density"]