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AP Enviro



Unit 3

3.7 Total Fertility Rate

1 min readmay 19, 2020


Karla Jauregui Sandoval

AP Environmental Science ♻️

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A factor that influences the size of the human population size is total fertility rate. Total fertility rate is the average number of children born to a  woman in her reproductive age. The total fertility rate has been declining in recent years although the TFR in developing countries remains higher than the replacement fertility rate (the total fertility rate at which a population replaces itself from one generation to the next without migration) of 2.1. The TFR may be decreased by access to birth control, education, women having jobs, or family planning. 

Image Courtesy of Wikimedia

Infant Mortality Rate 

Infant mortality rate of the number of children that die before the age of one. Some reasons for this can be the lack of sanitation, contraceptives,  no medical technology or not any access to healthcare. Crude birth rate is the number of births per 1000 people. Crude death rate is the number of deaths per 1000 people. 

A pediatric nurse checking recently born triplets in an incubator at ECWA Evangel Hospital, Jos, Nigeria

Image Courtesy of Wikimedia

Emigration and Immigration 

Other factors that influence the size of a country's population are emigration and immigration. Emigration refers to the number of people leaving the country which decreases a population size. Immigration is the number of people entering a country which will increase the population size. (Hint: Think- E stands for Exit.)


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