There's no pressure to join or not to join, just a matter of personal choice. The fraternities and sororities are student-run organizations, offering you opportunities to get leadership experience and hone your skills. All the Greek organizations participate in service activities to benefit worthwhile causes.
Greek membership is a great way to get involved in helping others.
Of course, membership in a fraternity or sorority brings a built-in circle of friends. For further information, a list of Greek organizations with Iowa chapters, and a map of the Greek houses on campus, click on the Greek System link above.