RNR 1001 Lecture : RNR Notes 005
Document Summary
Adjacent ecosystems often have a transition habitat with its own distinct vegetation and biota- ecotone. Human activities tend to simplify ecosystems by: altering trophic webs, reducing habitat complexity, reducing biodiversity. Unlimited resources results in exponential growth of living organisms- the rate of increase in numbers is proportional to the population size. The number of organisms is dependent only on how many are there and the growth rate. This is the logistic equation of population growth- exponential growth at small population sizes, slowing growth as the population approaches the carrying capacity. Does not identify the factors responsible for slowing growth: environmental resistance. Logistic population growth has given rise to the concepts of r-selected and k-selected species. Small, low reproductive investment per offspring, highly fecund, early maturity, short-lived, type iii survivorship. Poor competitors, often dominant during early succession, pioneer species, well adapted to unstable environments. Large, high reproductive investment per offspring, low fecundity, late maturity, long-lived, type i survivorship.
