The document discusses several topics related to population biology and human population growth, including: 1) Factors that influence population growth such as birth rates, death rates, and environmental limits. Populations exhibit either rapid exponential growth or slow steady growth depending on these factors. 2) Techniques scientists use to estimate population sizes such as sampling and mark-recapture when it is difficult to count all individuals. 3) Human population growth has increased rapidly over the past 150 years from 1 billion to over 7 billion currently due to declining death rates from improvements in health, education, and sanitation.

1. Population Biology

4. Graph of Exponential Growth P O P U L A T I O N S I Z E TIME

6. Population growth when carrying capacity is reached Carrying capacity TIME P O P U L A T I O N S I Z E

19. YEARS POPULATION IN BILLIONS