PLANULA Meaning and
Definition
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A planula is a term primarily used in the field of biology to describe a free-swimming, ciliated larval stage found in certain invertebrate animals, particularly in the phylum Cnidaria. It is a tiny, ovoid or pear-shaped organism that typically consists of a two-layered, hollow body with an outer ectoderm and an inner endoderm. The cilia lining the exterior of the planula are responsible for its locomotion through water.
Planulae are produced through sexual reproduction, wherein the eggs released by female cnidarians are fertilized externally by male sperm. These fertilized eggs develop into planula larvae, which are then released into the surrounding environment. The planula larvae serve as a dispersal stage, allowing the species to colonize new areas. They are particularly common in cnidarians such as jellyfish, sea anemones, and coral, where the planulae settle down and undergo further stages of development, eventually transforming into the adult forms of these organisms.
The term "planula" also has secondary usages in other contexts. In architecture, a planula refers to a small sheet or flat piece, often made of metal, used in the construction or ornamentation of buildings. Similarly, in geology, a planula may refer to a thin, flat piece of rock or fossil. However, the primary and most widely recognized definition of planula remains the biological one, which describes the free-swimming larval stage found in cnidarians and other invertebrates. Overall, the planula stage is crucial for the reproductive cycle and the dispersal of certain species, playing a significant role in the survival and expansion of these organisms in their respective ecosystems.
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The name given by Lankester to the embryo when it consists of the two primary germ layers only, viz., ectoderm and endoderm.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
Common Misspellings for PLANULA
- olanula
- llanula
- -lanula
- 0lanula
- pkanula
- ppanula
- poanula
- plznula
- plsnula
- plwnula
- plqnula
- plabula
- plamula
- plajula
- plahula
- planyla
- planhla
- planjla
- planila
Etymology of PLANULA
The word "planula" has its roots in Latin. It is derived from the Latin word "plānum", meaning "a level or even surface". The suffix "-ula" is a diminutive suffix in Latin. Therefore, "planula" can be understood as a diminutive form of "plānum", suggesting something small or little related to a level or even surface. In the context of biology, a planula is the larval form of certain cnidarians, such as jellyfish and corals.
Similar spelling words for PLANULA
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