The study of world population integrates so many themes and disciplines in the social studies because it encompasses all of human history--the rise of agriculture and civilizations, scientific progress, territorial conflicts, changing gender roles and more. It is also at the heart of human geography and how people came to dominate and alter the land and seas. In this modern age, where people have the ability to control fertility and reduce mortality, population studies involve personal choices, education, economics, social and cultural norms and politics. Learning about how the world's population grew to seven billion helps students understand contemporary challenges and discuss dwindling global resources. (Contains 4 notes and 4 online resources.)