Earth has experienced five major extinction events. This video from the PBS Evolution series explores all five major extinctions, and the implications of each for life as we see it today.
The program then looks into the future as we consider the impact of humans as the cause of a sixth extinction - happening right now.
This video guide organizes student note taking to focus on the main points of each section. The URL listed connects to the program YouTube site, and the sections of the table correspond to the chapters on the PBS DVD.