Reproduction in anemones is more often than
not found to be asexual. Anemones reproduce asexually by either longitudinal
fission or by pedal laceration. In pedal laceration, a new anemone is formed
once a grown anemone moves away from an area, leaving behind some fragments
of it’s pedal disc. When this happens, regeneration occurs and a brand new
anemone is made from the leftover pedal pieces of the other anemone.
While this is typical of most anemones,
sexual reproduction can occur as well. Anemones such as Urticina crassicornis
are hermaphroditic animals, meaning that an individual has both male and
female reproductive systems, however they typically produce only eggs or
sperm at any one time. The eggs are fertilized inside of the gastrovascular
cavity of the animal. Development of the eggs will take place either in
the surrounding ocean waters, or in the septal chambers of the animal. The
result of this process is a swimming planula larva which is either planktonic
(feeding on it’s own), or lecithotrophic (receiving it’s needs from the
yolk).
A juvenile anemone completely lacks tentacles,
and therefore remains as a free-swimming ciliated polyp until they form.
As the individual grows, it will eventually settle on some substrate and
attach by its pedal disc. Finally, the young anemone will form tentacles,
and remain in this polypoid form throughout the remainder of its life. If
this polyp decides to move (be it to escape predation or find a new habitat),
it may leave some of it’s pedal disc behind, and the entire life cycle will
start over again.
