Zooplankton are ‘drifting’ forms of life and are usually small, although there some are larger. The jellyfish and the Portuguese man-of-war are examples of larger types of zooplankton. They are not able to effectively direct their own movements, or propel themselves and are dependent on either wind or current to help them ‘drift’ along. There are some organisms, such as fish eggs, that belong to the zooplankton group only temporarily. Once they develop and grow up, they will leave the planktonic community to join their proper place in the marine world.