Coral reefs are many corals that come together and become a big group and life symbiotically with photosynthetic algae. Coral reefs have passed a long time of evolution, around 500 million years ago until now, They have passed a countless natural selection, and they still exist until now, but now; they’re face a new problem that might lead them to the extinction of coral. Not only because of the nature or predators, but also human acivities that give them a big impact. Now, many people try to rescue coral reef, to keep them alive and also to keep the ocean ecosystem and the biodiversity in the ocean, because coral reefs are one of the most important part of ocean ecosystem. “According to the fossils that found in China and Scotland, scientists estimated that the evolution of Coral has divided into two eras : Mesozoic and Cenozoic. Since the first organisms that has been estimated around 500 million years ago, in Cambrian period, Paleozoic era, called Scleractinians. The clearly ancestral Scleractinia lived in Middle Triassic, estimated around 247 – 237 million years ago, consisted of at least seven, possibly nine. The coral at that time did not build reefs, they just separate and make a small groups of coral or Phaleroid organisms of the shallow Tethys of Southern Europe and Indo – China. The Mesozoic era started during the Middle and Late Triassic, corals became widespread over the Tethys region, now their fossils are found around equatorial Panthalassa Ocean rim. Between the earliest Triassic corals and earliest widespread coral reefs, there was a time interval, around 20 – 25 million years. In the end of Triassic era, coral reef has a development collapse and after 5 – 8 million years of hiatus, they start to exist again at Jurassic era ( Jurassic reefs ). In Jurassic era, many new Scleractinian families are formed. The Late Jurassic was probably the all – time global maximum of Mesozoic coral diversity with at leas 150 genera recorded. The origin of the families of extant Scleractinia also have a high proportion in the Middle to Late Jurassic. Mesozoic era was end after the early Cretaceous. There many similarities between the coral in Late Jurassic and Early Cretaceous. In the middle of Cretaceous the reefs has been dominated. Rudist bivalves and enviromental pertubations are affected the reef development. And at the very late Cretaceous rudist bivalves did not affect the enviromental reef development anymore, it’s because a total extinction of rudists that can’t be explain and it’s make corals returned to a position of dominance.” ( http://coral.aims.gov.au/info/evolution.jsp ) Cenozoic era was start when One-third of all families and over 70% of all genera became completely extinct at or near the end-Cretaceous boundary. In Cenozoic era, there was two families that also the major component of Mesozoic era that still exist in Cenozoic era, they’re the Faviidae and Caryophiillidae. The evolutionary of modern corals is divided into three geological interval : (1) the Paleogene, at this time, the survivors of end Cretaceous and Late Paleocene extintions proliferated into a diverse cosmopolitan fauna, (2) the Miocene, at this time , coral was subdivided into the broad biogeographic provinces anf pre-cursors of most extant species evolved , and (3) the Plio-Pleistocene to present , the world went into full glacial mode and modern distribution pattern emerged , at this time , coral reefs have passed many natural selection and the remain of the corals have evolved and adapted with the earth’s condition. Corals are related to sea anemones and they also have a same simple structure, the polyp. The polyp use to capture small animal that swim near to him. It’s like a can that can open at just one end with a ring of tentacles surrounding him. The biggest component of coral reef is calcium carbonate, or limestone, they also the main component to build a new reef. After the reef dead, they will turn to coral skeleton and the living reef will build over the top of this, to build the new reef, the polyp will add new limestone to the massive base structure. The polyps make skeleton calcium carbonate surrounding themselves. Reef have many colourful coral, but how they can make many colourful coral ? The colour is come from the tentacles and coral polyps and also from the zooxanthellae algae that live in many species’s tissue. The family of corals is complicated, many corals look similar to each other. All but the fire corals are anthozoans, and they’re divided into two main groups. The first one is Hexacorals ( including the true stony coral and black corals, as well ad the sea anemones ), they have smooth tentacles, and they often have tentacles that multiples by six, and the Octocorals ( soft corals, seafans, organpipe corals and blue corals ) have eight tentacles, and every tentacle has tiny branches running along the sides. All coral are in the Phylum Cnidaria, the same as jellyfish. Coral reefs play an important role in ocean ecosystem, they symbolize the diversity of ocean, they also keep the balance of the ecosystem in the ocean. They are a home for countless species of fish, crustaceans, molluscs, echinoderms, sponge, worms and any other life forms. Coral reefs are very suitable for a lot animals to life because it’s a safe place for many animals to hide from the predator. Even though there is the biggest communities in the ocean ecosystem, but they still have some requirements to survive, they can’t life in every water condition. Coral reefs need warm ( but not too warm ) water, and they can’t survive in a water that have a high nutrient concentrations or runoff from the land create dense layers of algae, fungi, or sediment. Coral reefs also give many benefits to human. Coral reefs can be a good place to go, many people go snorkling to see the coral reefs, because coral reefs are very beautiful and amazing and there are many species life there, it will make a lot of money, because many tourists will come to see the incredible of ocean life from coral reefs , and because of many people come to see the coral reefs , it will open new job for many people. Coral reefs also give a food for people that live near the beach because there are many fishes , crabs or anything around the coral reefs that people can eat and coral reefs can be a natural barrier to protect coastal cities, communities and beaches. Some of corals can be a good medicine to cure some dangerous illnesses and diseases. Coral reef also become a barrier shield along shorelines to minimize the impacts from storms such ad cyclones, hurricanes or typhoon wave to come to the beach. Now, coral are meeting a big problem that can lead them to the extinction, the cause of the destruction of coral reefs have divided into two group, the first one is because of the natural, like global warming. Global warming make the earth’s temperature rise everytime and it will effect the temperature of the ocean too. As the temperature rise, mass coral bleaching events and infectious disease outbreaks are becoming more frequent. Additionally, carbon dioxide absorbed into the ocean from the atmosphere has already begun to reduce calcification rates in reef-building by altering seawater chemistry through decreases in pH. This process is called ocean adification. Another reason is because the invasive species that destroy the coral reef, for example sea urchin, sea urchin is the predator of coral, it damage the corals and maybe it will kill the coral. The second one is because of human activities, for example because of human activities that might be increase the greenhouse gases that result in climate change and ocean adification. Climate change = Ocean change, it means that when the climate changed, the ocean also start to change to the condition that make coral can’t survive and maybe kill them slowly. The world’s ocean is a massive sinks that absorb carbon dioxide ( CO2 ). Even if the global warming was happen very slow, it still change the ocean chemistry. The other cause is because the destructive fishing and pollution, many fishermans were using TNT for fishing, but it will destroy the reefs extremely, because the explosion will effect to the corals in the distance of the explosion, it will kill the corals directly, and will destroy the ecosystem in the ocean, and it also kill other animals that life near or in the reefs and sometimes fisherman also use poison for fishing, it worse than use the TNT because it will take a long time to make the effect of the poison disappear, it will kill every coral in the distant that the poison can reach, and it takes a long time to recover the ocean and to plant the coral. same with the poison, the pollution also takes a long time to recover the ocean, but sometimes the effect not severe as the poison.” If the coral reef destruction keeps happening, it will bring a huge effect, not only to the ocean, but also human. For the ocean, many species will lost their home and because they did not have a safety place to protect them from the predator and they will find many difficulties to find the food , in result it will led many species to the extinction and ocean will lost their diversity. If the coral reefs totally destroyed, it will led to the collapse of the ocean, because coral reefs are very important. Coral reef is one of the center of the ocean, and if they destoyed, than the ecosystem can’t be balance, the fish, crustaceans and many animals will die, and then the predator will die too because there no food too eat. Not only impact to the ocean ecosystem, it also will impact to the human, the one who will feel the impact first is the people that life near the beach or in a small island, their food will start to decrease slowly, and they lost their job, the bigger impact, the natural disaster will get bigger everytime because there are no barrier protection along the shorelines, and it will affect to the financial. “One example of the coral reef destruction is Great Barrier Reef. According to the survery that has been held by Great Barrier Reef Marine Park Authority and Queensland Park and Wildlife Service, the last two years, the global coral bleaching led to widespread coral decline and habitat loss on the Great Barrier Reef and last year, bleaching in Marine Park has spread until 344.000 square kilometres, it was a huge number and it impacts to many aspect in Australia. Many reseachers and scientist are trying to find the cause why the bleaching of Great Barrier Reef and they also try to recover it. Many researchers have estimated that the loss of shallow water coral reef will up to 29 percent. Some sites have suffered significant damage ( it cause 97% coral loss ) and the recover of coral reefs are very slow, while other received less damage and still have moderate coral cover.” ( http://www.gbrmpa.gov.au/about-the-reef/reef-health ) There are many organizations and goverments keep trying to rescue the coral reefs. They spend a lot of money for coral reefs recovery. Government also makes a new law about coral reefs protection, the scientist and researchers are trying to find a way to rescue the coral reefs, sometimes they do the experiment like plant the corals in some new place, and the others was planted on the top of the death corals, they hope that it will be success and the corals will get bigger and grow up, but until now it haven’t succeed yet, because there are many people that irresponsible to the life of coral life and that’s make the destruction of coral reef become faster than the recovery of coral reefs. For the citizens, they can also rescue the coral reefs. For example, when they do the snorkling, they no need to touch the coral or don’t do anything that can damage the coral, and you can donate to the organization that care about the coral & ocean and the last, for the fisherman, they can use a eco-friendly stuff for fishing, they no need to use the TNT or poison that can damage the coral and the ecosystem around it because it’s not only damage the corals , but also kill a lot of animals that lifes near the reefs, and the last but not least for the factory that build near the beach, they can’t dispose the waste to the ocean. But if they have to dispose it to ocean, they need to filter the waste of the factory first, so it won’t damage the coral and the other animals critically. We have to rescue the corals because we are the main cause of coral reefs destruction and we are the only one who have to take the responsibility of it and also the only one who can save the corals because destruction of coral bring many impacts to us, so if we rescue coral it means we also save the human kind. For now, maybe we just feel a small impact from the destruction of the coral, but the impact getting bigger everytime, and at the last we will regret why we didn’t rescue the coral, so it’s better to do it as soon as possible.