Marine Biology

The Interesting Reproductive Habits of Coral

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"The Interesting Reproductive Habits of Coral"
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Coral, like almost every other living organism that calls the ocean "home," is a fascinating animal. The coral head, an image most are familiar with at the mention of coral, appears to be a single organism, while it is actually comprised of many individual, yet identical polyps. So how do those little coral polyps reproduce to create amazing formations like the Great Barrier Reef?

Corals reproduce both sexually and asexually. Although they predominantly reproduce sexually, an individual coral polyp may utilize both modes of reproduction during its lifetime. Corals can be either male or female, or they can have both male and female reproductive cells (hermaphroditic). Corals that reproduce sexually can do so by either internal or external fertilization. Brooder polyps, which internally fertilize eggs, harbor the eggs for days or even weeks, and once developed, the free-swimming larvae are released into the water where they settle and grow into new polyps. Broadcast polyps fertilize the eggs externally by releasing eggs and sperm into the water at the same time. This spawning process disperses the eggs over a larger area, and after a few days the fertilized eggs will develop into free-swimming larvae. These free-swimming larvae, like those fertilized internally, will settle and grow to create new polyps.

Corals can also reproduce asexually to allow growth of the colony. Genetically identical polyps within a coral head can reproduce asexually by either budding or through division. Budding, which occurs when a portion of the polyp breaks off to form a new polyp, allows the polyp to replicate itself several times while maintaining tissue connections within the colony. Asexual reproduction by division allows the formation of two polyps which are each as large as the original polyp. Corals have the incredible ability to grow from broken-off pieces of the original colony; this allows the coral colonies to grow when damage is sustained due to environmental disturbances.

Whether born of sexual or asexual reproduction, corals have a slow growth rate of approximately .8 inches per year, although some may grow more than others. Factors such as water temperature, food availability, salinity, and light intensity play an important part in the growth of corals and their ability to reproduce.

More about this author: Brandi Carpo

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