EVR 1001 Lecture Notes - Lecture 5: Placer Mining, Extrusive Rock, Silt

• School: UCF
• Department: Environmental Sciences
• Course: EVR 1001
• Professor: Patrick Bohlen

Document Summary

Demography: the study of human populations and population trends. Crude birth rate (cbr): the number of births per 1000 individuals per year. Crude death rate (cdr): the number of deaths per 1000 individuals per year. Global population growth rate = [cbr cdr] / 10 = growth rate in % e. g. , [20 8] / 10 = 1. 2 percent. Doubling time: the number of yars it takes a population to double. Example: a population doubles every 40 years (40y). Technology has allowed the species to overcome some environment resistance. The rule of 70 can be used to estimate the doubling time (dt) in years. Example for 2% growth: 70 / 2 35 years. Total fertility rate (tfr): an estimate of the average number of children that each woman in a population will bear. Replacement level fertility: the total fertility rate required to offset the average number of deaths in a population and for the current population size to remain stable.