EEMB 2 Lecture Notes - Lecture 5: Logistic Function, January 30, Exponential Growth
Document Summary
No natural populations can maintain exponential growth indefinitely. Pop. density fluctuates around a constant number. As pop size increases resources become limiting for growth and reproduction. Carrying capacity (k)-the maximum population size that an environment can support. Population growth slows as its density approaches. Modifies the exponential growth model to include changes in r as the population moves towards k. At large values of n, the value of the part within the parentheses becomes small and the population growth is small. When pop size is below k pop growth increases. When pop size is near k pop growth decreases. Small organism population fits the model well however many populations do not stabilize at k but rather deviates from sigmold curves. Why does it not fit for most population: Each individual added to the population has same negative effect on population growth. Population are large and density is important in regulation.