The document discusses key concepts in population and demography including:
1. Population refers to a collection of human beings that share characteristics that can be analyzed. Population growth rate measures the increase in a population over a period of time.
2. Demography is the statistical study of human populations and how they change over time due to factors like birth, death, migration, and aging.
3. Thomas Malthus' theory proposed that population increases faster than the food supply, pushing people to the verge of starvation. The demographic transition model shows populations transitioning through stages of high then low birth and death rates.