Barnacle
| Barnacles | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Scientific classification | ||||||||||||
| ||||||||||||
| Orders | ||||||||||||
A barnacle is a type of arthropod, in the subphylum Crustacea and is distantly related to the crabs and lobsters. However, barnacles are in the infraclass Cirripedia. Some authorities regard this as a full class or subclass, and the orders listed at right are sometimes treated as superorders. There are around 1,220 barnacle species currently known.
Barnacles have two larval stages. The first is called the nauplius which spends its time as part of the plankton, floating wherever the wind, waves, currents, and tides may send it, eatting and molting. This lasts for about two weeks until the sixth stage is reached. At this point the nauplius metamorphosis into a nonfeeding, stronger swimming cyprid larva.They then settle down in an area where environmental cues indicate is a safe and productive environment.If it doesn't the larva will die.
When an appropriate place is found the cyprid larva cements itself to the surface and then undergoes metamorphosis into a juvenile barnacle.Like most invertebrates, barnacles are hermaphroditic and alternate male and female roles over time. Typical barnacles stick their legs in the air, and develop six hard plates to surround the body. For the rest of their lives they are cemented to the ground, using the feathery legs to capture plankton and gametes when spawning. They are usually found in the intertidal zone.
Since barnacles often attach themselves to human-made structures, sometimes to their detriment, and in particular to ships, they are classified as fouling organisms.
However, some members of the class have quite a quite different mode of life. For example, members of the genus Sacculina are parasitic on crabs.
The Barnacle Goose gets its name from the ancient European belief that it grew from the Gooseneck Barnacle, Pollicipes polymerus; eggs and goslings of this bird were never seen because it bred in the remote Arctic. As such, it was counted as a fish, and could be eaten by Catholics on Fridays, when meat used to be forbidden.