Corals and adaptations

This essay has a total of 689 words and 4 pages.


Corals and adaptations




Corals and Adaptations

Coral reefs are among the most diverse and productive communities on Earth. They are found
in the warm, clear, shallow waters of tropical oceans worldwide. Reefs have functions
ranging from providing food and shelter to fish and invertebrates, to protecting the shore
from erosion.

Although many corals resemble plants, they are actually members of the animal phylum
Cnidaria. Most corals are colonial, which means that each coral is made up of many
individual polyps connected by living tissue (the coenosarc). Each polyp has a cup-like
shape with a ring of tentacles around a central opening (pharynx) that functions as both
mouth and anus. The tentacles are tipped with stinging cells called nematocysts. Corals
use the nematocysts to defend themselves and to capture prey. The body wall consists of
three cell layers: the outer or ectoderm, the middle or mesoderm, and the inner or
endoderm. There is no skeleton inside the polyp itself. Instead, the polyps sit on top of
an external skeleton that is made from the polyp's secretions.

One of the most interesting findings about coral are some of their reproducing habits.
Horn coral, for example, depend on waves to break off pieces and carry them to new
locations where the broken pieces start new colonies. The more famous coral forms huge
deposits that take on the shape of small, underwater mountains of calcium carbonate.
Corals are benthic organisms in the fact that they are stationary for the most part, and
do not swim or drift in the ocean. All coral feed on plankton. Soft coral are filter
feeders, filtering out plankton as the current passes through the porous structure of the
coral. Hard coral have tiny "critters" located inside a limestone shell that rely on
plankton that float by as their food source.

Since they are very sensitive, coral require a very specific environment in order to
survive. They are found generally in warm, shallow areas of the tropical oceans.
Although they are best developed in temperatures from about twenty-three to twenty-five
degrees Celsius, coral reefs can be found in temperatures as low as eighteen degrees
Celsius. Corals are restricted to seawater with a salinity ranging from thirty to forty
parts per thousand. They also require a concentrated amount of calcium carbonate to
assist in the process of forming their skeleton. The shape, size and structure of the
coral are directly related to their location in the ocean, and depth. Coral located near
the surface tend to be flexible in order to flex and sway with the wave action and tidal
currents. The water currents and wind can also play an important role in the
development of coral reefs. The water currents shape and mold the coral, and the wind
both affects the currents and shapes the coral when it rises above the water to form small
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