Lincoln Cent, Memorial Reverse (1959-2008)
The Memorial Reverse was the successor of the Wheat Ear (wheat head) penny. The main reason for the change was because of the complete boredom of the Wheat Ear in the general population. The Release of the penny in 59' was also to celebrate the 100th anniversary of Lincoln's birth. The memorial was designed by Frank Gasparro in the same year of its release.
A Change In Metal (1982)
In 1982, the price of copper rose drasticly causing the amount of copper in the penny to rise in value past the amount one cent. So in 1982 the 136 year old tradition of having a 95% copper penny changed to having a content of 97.2% zinc(with the exception of the 1943 pennies which were made of steel). During the transition though, there were seven different versions printed that year.
Possible Ending of the Memorial
Though no official statement has been made, rumors of the ending of the Memorial Reverse are starting to circulate as the production of the one cent is becoming more expensive to produce than its face value.