The mind dulls when we are faced with large numbers that are outside of our daily experience. A million, a billion, what’s the difference? We tend to put them in the same category—large numbers, and let it go at that. But in dealing with human populations, as in dealing with money, a billion is a lot different than a million. For one thing, a billion (1,000,000,000) has three more zeros in it than a million (1,000,000). That means a billion is equivalent to 1,000 million.
Suppose your parents offer you two alternatives for your allowance: They will give you ten dollars every day for the year, or they will give you a penny the first day, and double the penny every day for a year. Which offer would you take? After you write your choice, you will do a onemonth sample which will tell you which would be the better offer.
Take the copy of the calendar for February and a calculator, and write in each day the total amount you will have in your pocket. At the end of the month, write your grand total.
Which is the best deal?
What has happened here?
Does this happen with some populations?
What would the numbers be like if you substituted bacteria for pennies? The following investigation will help you to find out.

