Corals(Marine Animals of Phylum

Cnidaria)Science V

The Invertebrates1. Phylum Porifera (Sponges)2. Phylum Cnidaria (Hollow-bodied animals)3. Phylum Platyhelminthes (Flatworms)4. Phylum Nemathelminthes (Roundworms)5. Phylum Annelida (Segmented Worms)6. Phylum Mollusca (Soft-bodied animals)

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7. Phylum Echinodermata (Spiny-skinned animals)8. Phylum Arthropoda (Multiple-legged animals) a. Class Crustacea (Crustaceans) b. Class Chilopoda (Centipedes) c. Class Diplopoda (Millipedes) d. Class Arachnida (Arachnids) e. Class Insecta (Insects)

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Look at the picture. Can you tell what this is?Motivation

The tiny sea animals know as true corals often form colonies that are attached to rocks or reefs. The individual animal stays here during its lifetime; after it dies, the skeleton remains. New corals grow above them. This process goes on and on until large buildings of corals are formed. The coral building is called coral reef.

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When coral colonies grow close to the shore they form the fringing reefs. Fringing reefs move slowly away from the shore. This is because a coral reef grows mainly towards the ocean side. At this side the ocean waves bring the corals water and food.

As the fringing reef continues to grow oceanward, it becomes a barrier reef. An example of a barrier reef is the Great Barrier Reef of Australia (2000 km long 150 km wide)

Corals (Marine Animals of Phylum Cnidaria)Stony corals are reef-building species.

Coral reefs are built when the exoskeletons of corals, composed of calcium carbonate or lime, accumulate in large quantities. This large accumulation happens as the limy exoskeletons of one generation of stony corals are secreted on the exoskeletons of the past generation. Corals can take millions of years to form a reef.

Presentation

Factors that Contribute to Reef FormationAside from corals, other organisms with

skeletons composed of calcium carbonate (or lime) contribute to the building of depositing limestone sheets over the surface of the reefs.

As organisms living in canal reefs die, their bodies are broken down by grazing organisms like fish and sea urchin as well as natural forces like wave action. Their limy skeletons settle and contribute to the structure of the reef.

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Importance of CoralsCoral reefs are one of the most beautiful

and colorful natural resources on Earth. Did you know that the Philippines is one of the countries with the most extensive coral systems in the world? Some of them can be found in Palawan, Sulu, and Southern Mindanao.

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Coral reefs are important due to several reasons:1. Coral reefs are the natural habitats for many sea animals like sponges, mollusks, crustaceans, and echinoderms.

Some of these animals graze on algae that grow on the surface of the reef, others feed on smaller animals. All in all, the organisms that inhabit coral reefs participate in the complex network of eating and being eaten.

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2. Coral reefs are the breeding ground of fishes and other forms of marine life.

Coral reefs provide environmental conditions that favor the growth and development of young sea animals.3. Coral reefs provide rich sources of marine food.

Coral reefs provide an abundant supply of fish, shrimp, crab, and other edible marine animals.

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4. Coral reefs serve as a rich recreational area and provide entertainment to people who enjoy exploring underwater marine life.

5. Calcium carbonate that is found in coral reefs is an important building material.

6. Coral reefs protect coastlines from strong waves and water currents.

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Factors Contributing to Destruction1. Dynamite Fishing

A single explosion can kill all the fishes in the area. With decreasing number of cnidaria, there will be less corals.2. Muro-ami Fishing

Muro-ami fishing uses movable net bag that is spread around the reefs. The young fishermen (ages 9-16) hammer the corals with rocks or other objects. This drives the fishes

out of their homes and into the waiting nets. Muro-ami fishing leaves behind a coral reef completely destroyed.

With no regard for its beauty and economic value, Muro-ami fishing contributes to the destruction of the entire coral reefs.3. Pollution of seawater destroys all marine life forms.

Describe ways of saving the coral reefs.

Application

SAVING THE

CORAL REEFS

GOOD FISHING

PRACTICES

REFORESTRATION

INDUSTRIAL AND

AGRICULTURAL WASTES

CONTROL

CONTROLLED LOGGING

ACTIVITIES

SEAGRASS BED

PROTECTION

SILTATION CONTROL

How Can We Save our Beautiful Coral Reefs?1. Our government, through the Bureau of Fisheries, provides and implements regulations regarding collection of coral but enforcement is difficult.2. Prohibit the destruction of sea animals by banning dynamite fishing.3. Strict rules regarding the discharge of pollutants into the sea must be implemented.