Within one linear centimeter of your lower colon there lives and works more bacteria (about 100 billion) than all humans who have ever been born. Yet many people continue to assert that it is we who are in charge of the world.
— Neil deGrasse Tyson, Comment on "I am Neil deGrasse Tyson -- AMA" (2012)
Source: http://www.reddit.com/r/IAmA/comments/qccer/i_am_neil_degrasse_tyson_ask_me_anything/c3wguoh
A Reddit comment on his 'I am Neil deGrasse Tyson -- AMA' thread, March 2012.