This document discusses various attributes of populations and population growth. It describes birth rate, death rate, population density, age distribution, and sex ratio as key attributes of populations. Population growth curves can take a sigmoid or S-shaped form, with phases of lag, acceleration, and plateau, or a J-shaped form with rapid exponential growth until environmental resistance increases. Population change over time is determined by the balance of births, deaths, immigration and emigration. The carrying capacity of the environment limits population growth.