BIOL 308 Lecture Notes - Lecture 15: Logistic Function, Ecosystem Engineer, Carrying Capacity
Document Summary
"ecosystem engineering": carrying capacity also follows logistic growth. Mutualism doesn"t directly helps species growth, but by generate carrying capacity (generating habitat); and it"s reciprocal. Requirement for equilibrium: at any density, species 1 can generate a carrying capacity higher than the current density for species 2 (reciprocal) Facultative, (minimum k does not intercept 0, there is a equilibrium when in absence of one species, the other species still has positive carrying capacity) At individual level: demographic , chance event that affect individual survival (genetic, pure luck), the probability that independent event collectively affect the whole population decrease exponentially with the increase of population size. Population level: environmental fluctuations, affect the survival and reproduction of population. The old models assume that overall fitness of population remains the same between years. A long term growth linked to variability from fluctuation between years (demographic and environmental) Variance in growth rate depends on variance in environment, and the variance in population decreases with population size.
