All Subjects



AP Enviro



Unit 3

3.7 Total Fertility Rate

1 min readmay 19, 2020

Karla Jauregui Sandoval

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.)

🎥 Watch this video on total fertility rate.


Was this guide helpful?

Join us on Discord

Thousands of students are studying with us for the AP Environmental Science exam.

join now

Browse Study Guides By Unit

Free Response Questions (FRQs)

Multiple Choice Questions (MCQs)

Unit 1: The Living World: Ecosystems

Unit 2: The Living World: Biodiversity

Unit 4: Earth Systems and Resources

Unit 5: Land and Water Use

Unit 6: Energy Resources and Consumption

Unit 7: Atmospheric Pollution

Unit 8: Aquatic and Terrestrial Pollution

Unit 9: Global Change

Play this on HyperTyper

Practice your typing skills while reading Total Fertility Rate

Start Game