Coral notes!
Phylum Cnidaria and the class _______________
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There are over 800 known Hermatipic species
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Hermatipic- ___________________________
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Coral reefs are the most biologically diverse ecosystems on earth,
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They are important because they are a source of food (Butterfly fish); protect coastlines
(from___________ and ________________), give homes and spawning/ nursery
grounds for fish provide jobs to local economies from fishing, recreation, and tourism
for humans. Provide new medicines.
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They are also radially symmetric
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Most reef-building coral look yellow to brown because of the symbiotic algae that live within
their tissue; other corals contain protective pigments that give them bright colors. Because
exposure to ultraviolet light can destroy DNA, so some coral species dwelling in shallow waters
have evolved protective pigments to reduce the negative effects of ultraviolet light. These
pigments are often blue, purple, or pink and account for the bright colors found in some corals.
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In addition, observations of coral color can be misleading as corals may appear to have different
coloration above and below the water's surface. As water depth increases, the number of visible
colors in the light spectrum decreases. Exposure to artificial light, such as a camera flash, adds
light that is lost at depth, capturing the true colors of many corals.
Soft coral
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Also known as ahermatypic (non reef building) coral, they do not produce a
_________________________ skeleton
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Often called octocorals because their tentacles come in groups of 8
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Mostly colonial because they don’t build reefs
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The inner core of the colony consists of gorgonin which is a flexible, fibrous wood-like
protein. This gives the soft coral colony the ability to flex with the ocean waves and
currents
Soft coral colonies look like trees, bushes, fans, whips, and grasses. Colonies are usually
attached to the substrate at a single point at the base of a stem and most species have some
level of branching in their structure.
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A soft coral colony has the growth potential of two to four cm per year.
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These coral species do not secrete calcium carbonate skeletons so their polyps do not contain
calyx, theca, tabulae, septae, or a basal plate. Tentacles and mesenteries are present in groups
of eight, rather than six.
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In addition, their tentacles are often fringed and many soft corals do not contain zooxanthellae
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Contains sclerites (primitive skeletal system, like sponges) in cells on the outside of the
colony found in coenenchyme, (which is _____________________________) between
the polyps.
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Sclerites made of protein and calcium carbonate. And allow the coral to grow
vertically, give coral a spiky or grainy texture.
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Inner core of the colony consists of gorgonin which is a flexible wood-like
protein. This gives the soft coral colony the ability to flex with the ocean waves
and currents
Some are also encrusting
Hermatipic- Reef building coral
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Contains a basal plate which is the bottom of the calyx that the polyp builds
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Net benefit of the world's coral reef ecosystems estimated to be __________________
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Shallow coral reefs grow best in warm water (70–85° F or 21–29° C) and prefer clear
water because they happen to like eating
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Generally grow best at depths shallower than 70 m (230 ft). However, mesophotic coral
ecosystems, where the dominant habitat-forming species can be comprised of coral,
sponge, and algae species, are found a depths between 30 and 150 m in tropical and
subtropical waters.
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Corals also need salt water to survive (between 32 to 42 parts per thousand), so they
also grow poorly near river openings with fresh water
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Have zooxanthellae while deep and soft coral do not
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Most corals feed on zooplankton at night
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They eat zooplankton that supplies the coral and its zooxanthellae with
nitrogen, an element essential to both organisms, but one that is not produced
in sufficient amounts by either. The symbiotic relationship between corals and
zooxanthellae facilitates a tight recycling of nutrients back and forth.
Also collect fine particles in mucous film which are drawn by cilia into the polyp's
mouth. Some species are entirely mucous suspension feeders
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Branching corals appear to be more self-nourishing (autotrophic) because multilayered growth allows greater surface area to intercept light. In addition the
polyps of branching corals tend to be small, thereby exposing the maximum
area of zooxanthellae to light.
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Corals that are more heterotrophic typically are spheroidal and have a singlelayered skeletal structure; less plant material exists in the thicker tissues of
massive corals as well. Heterotrophic corals possess thicker, larger polyps that
allow for the capture of more plankton. Their form also maximizes the surface
area of plankton-intercepting tissue
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The amount of energy that corals derive autotrophically and heterotrophically
varies by species and situations. However the proportion of energy derived from
photosynthesis ranges from over 95% in autotrophic corals to about 50% in the
more extreme heterotrophic species.
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Prey ranges in size from small fish to zooplankton, depending on
____________________________________
Deep water coral
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Deep sea corals live on in deeper water from 50 m to over 3,000 m
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A few species also live in shallower, cold water in the northern latitudes.
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Found in all oceans
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Like their shallow-dwelling relatives, deep-sea corals exhibit high biodiversity.
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Don’t contain __________________(no light)
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Don’t know the extent of communities because they live so deep
Zooxanthellae
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an algae that gives off __________ and _______________________
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polyp gives the algae __________________
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Thats why coral reefs grow near the surface
Algae enhance the coral’s ability to synthesize calcium carbonate
Coral Bleaching
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When algae leave, due ___________________ or a change in ________
Feeding
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Polyps extend their tentacles to capture prey, stinging them with nematocyst
cells, and then drawing them toward their mouths.
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Also collect fine particles in mucous film which are drawn by cilia into the
polyp's mouth. Some species are entirely mucous suspension feeders
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Prey ranges in size from small fish to zooplankton, depending on size of the
coral
Reproduction
Can be either asexual or sexual
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Budding- ________________
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Fragmentation- __________________
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New polyps bud off from parent. This occurs when the parent polyp reaches a certain
size and divides. Continues throughout the animal's life and produces polyps
_____________________________________
Allows a portion of an entire colony to establish a new colony. The separated
individuals start new coral colonies that are genetically identical to the parent colony
Broadcast Spawning
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3/4ths of all stony coral species are broadcast spawners
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Produce male and/or female gametes that are released into the water in large numbers
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Allows them to______________________________.
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Have lots of kids at one time to compensate for how many die a terrible
depressing death, while their parents watch, and can’t do anything about it.
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Occurs as a synchronized event, very important
_________________________________________________________________
Usually occurs in response to environmental cues.
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Long-term cues may be related to_______________, _____________,
or rate of_____________________.
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The short-term control is usually based on lunar cues
Remaining 1/3 of coral species are brooders
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Only__________________________.
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The gametes are negatively buoyant and transported by waves and current before
sinking
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They are taken in by female coral polyps containing egg cells fertilization occurs inside
the female coral and produces a _________________.
The planula is released through mouth of female when it is old enough to settle very soon after its
release.
Aggression
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Overtopping
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used mostly by fast growing species
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The faster growing coral just grow over the other coral
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The covered coral gets ____________________________and eventually dies
Aggression
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Involves extruded digestive filaments and sweeper tentacles. Typically results in the
death of some of the other’s polyps.
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Cells are specialized to perform various functions
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Very limited ___________________________
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Have a simple stomach (also called a _______________________) opens only on one
end, and a ring of tentacles.
Polyps
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The stomach opens at the center of polyp and is surrounded by tentacles. This
single opening is used both to ingest food and to expel waste. The tissue lining
the stomach called the gastrodermis. Between the epidermis and the
gastrodermis is a jellylike tissue called mesoglea (like in jellyfish). Septa, or
vertical plates, are also present within the gastrovascular cavity; they support
the mesenteries (internal folds) of the stomach. The mesenteries increase the
surface area of the stomach cavity and also contain the reproductive cells.
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In hard coral, the edges of the mesenteries support long mobile filaments that
can protrude through the mouth and capture food or assist the coral colony in
competing with its neighboring organisms for space to grow. At the bottom of
the stomach is the basal plate.
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No central_____________________________.
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While appearing to be a single organism, many coral are actually a colony of many
individual, identical, coral polyps.
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Are only a few millimeters in diameter
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The polyps of hard corals sit in a _________________ that is produced by the coral with
________________________
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The walls surrounding the calyx are called ______________ and the bottom is the
__________________________
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Basal plate is a_________________________. The ridges grow vertically and project
into the base of the polyp.
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Tabulae are ________________________that allow for upward growth by isolating the
surface from the skeleton.
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The individual polyps are connected via a system of gastrovascular canals that allow for
the sharing of nutrients and symbiotic algae. These canals run through the coenosarc,
which is tissue that connects individual polyps at the surface of a coral colony. The outer
tissue of the polyp is the epithelium or epidermis.
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Tentacles for this group of corals are typically smooth and occur in sets of six (except in
soft coral). Used mainly for defense and to capture and move food to its mouth.
Tentacles may be retracted when stressed to protect them from predators and the
elements. Some species also retract their tentacles during the day, but extend them at
night, to feed on plankton.
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The tentacles contain stinging cells, called nematocysts or cnidae. These stinging cells
cause no harm to humans with the exception of Fire Coral, who’s sting is painful for
weeks.