How do gelatinous animals reproduce?
A survey of reproductive methods among gelatinous animals will reveal a bewildering array of methods for spreading the genetic word. Cnidarian jellies typically undergo an alternation of generations, with a sessile (attached) asexual polyp phase and a free-swimming sexual medusae phase. The medusa is the form most familiar to everyone. Among most scyphozoan jellies, males and females release eggs and sperm into the surrounding water. The fertilized eggs develop into tiny ciliated larvae known as planulae that eventually settle out on appropriate substrates. These develop into polyps (scyphistomae) that may divide asexually to colonize an area. Eventually the polyps undergo a process known as strobilation in which tiny medusae known as ephyrae are serially released. A strobilating polyp resembles a stack of dinner plates, with the largest, most developed ephyra at the end. Ephyrae quickly develop into the medusa form and eventually mature as separate male and female individuals. Many hy
