BIOL 117 Lecture 15: Chapter 15 - Population Ecology
23 Jul 2016
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2500 in 1940s, then dropped back to aprox. St. george island: caribou population increased slightly then dropped to about. 50, has remained there since: potential increase: move food on st. paul, better shelter, no predators, potential decrease: food not replenished, disease, sheep population in south australia ~ sigmoid growth(see below) **growth in pop. ecology refers to both increase and decrease in population. Exponential growth - bacteria divides by 2 every 24 hours. Sigmoid growth pattern: early exponential growth. K = carrying capacity: limits environment places on growing population. Population size is always chasing k: decelerating growth rate, fluctuation around max. average for population. It changes with the environment*: point where population size is in equilibrium with resources, number of individuals from species that can be supported by environment, number of individuals that can live in a population. Population is decreasing because k will be negative. Population will grow to t k became k will be positive.
