Zero Population Growth

Zero population growth (ZPG) occurs when there is no change in the amount of people in a given time. Let's say that Regular City, between Plainville and Example Counties, had ZPG last year. Does this mean that no one died or was born last year? You might think so, but it's not that simple. When we talk about no change in the amount of people, we mean no net change. No net change means that the number of people born equals the number of people who have died. Thus, zero population growth occurs when birth and death rates are equal. Birth rate refers to the amount of births per 1,000 people per year, while death rate refers to the amount of deaths per 1,000 people per year. So in order for Regular City to have ZPG, Regular City has a birth rate of 33 and a death rate of 33 as well. When dealing with population growth, we must also take into account people moving in and out of an area. When dealing with Regular City, we assumed there was no emigration or immigration. In other words, we assumed no one left Regular City and no one entered Regular City. In the real world, that's not usually the case. In reality, zero population growth occurs when births and immigration equal deaths and emigration in a certain time period.