There are three main subclasses of gastropods; the Prosobranchia (ocean snails), Opisthobranchia (sea slugs, sea butterflies and sea hares), and Pulmonata (land and freshwater snails and slugs). Each of the subclasses has evolved in their own way and members differ in their reproduction and life cycles within the subclasses. The gastropod folks are so large it really is impossible to spell out living cycle of each one individual species, but a majority of general rules do apply. The more evolved the species, the more complex their reproductive cycle in addition to their biology. Here we will look at the life span cycle of a gastropod through various examples and how they differ with regards to the type. In the present times, variations in the act of copulation have been modified. We always seem to wonder at some point in us as to why we are the way that were. Why do we behave in a very certain method that others don't? Why is it that I and my sibling or my best friend has different likes, choices and hobbies? And most importantly, exactly why are we different from the other person in any way?