-The world's first coral reefs occurred about 500 million years ago, and the first close relatives of the modern corals developed in southern Europe at about 230 million years ago.
-The Great Barrier Reef is relatively young at just 500,000 years old.
-The current reef's structure is much younger at less than around 8,000 years old.
-Most modern reefs are formed on hard surfaces in the ocean, such as a base of an old reef that died during a period when sea level was lower, or the edge of a rocky island.
-Some coral reefs form in the deep ocean and are called atolls.
-Atoll starts life as a fringing reef, then becomes more of a ring growing on the shrinking land-mass, until the land disappears and just the coral circle remains.
-In some other cases, the coral growth is unable to keep pace with the sinking island, and sunken dead reefs have also been found.
-It was until the mid-18th century that corals were recognized as animals, not plants as what people used to thought.
the corals size:
-The corals size are individual polyps range from 3 - 56 mm in diameter or height; while colony size varies from 75 mm -1500 mm (1.5 m) in width, height or in length.
-Coral polyps: Coral reefs consist of hundreds and thousands of soft-bodied, invertebrate animals, which have no backbone which are known as coral polyps.
-The individual polyp is radially symmetrical and has a tubular body with tentacles surrounding the mouth at the upper end.
-Each polyp’s body wall consists of two layers of cells, an outer layer called the ectoderm and an inner endoderm layer.
-A gelatinous material called mesogloea is found in between these two layers.
hard corals:
-Hard corals build reefs by growing atop the stony skeletons of previous coral colonies.
-It consist of limestone cases made by coral polyps extracting calcium from seawater.
-These limestone cases form a so-called house for the coral polyp, consisting of a floor, outer walls and a number of internal partitions.
-Inside corals’ clear outer tissues live microscopic algae, which transform sunlight into sugars through photosynthesis.
-The hosts help themselves to some of the sugars and gain some colour through photosynthsis.
-Hard corals form the backbone of the reef. Corals are remarkable creatures, they can form vast colonies and habitats.
reproduction of corals:
-Corals reproduce in two ways- asexually and sexually.
-Some corals divide to form new individuals, known as asexual reproduction.
-Sexual reproduction takes place as mass spawning, where polyps release millions of eggs and sperm.
-Polyps are either male or female or both male and female.
-After the eggs and sperm are released, they float to the surface.
-The fertilised eggs that escape predation by other animals hatch into larvae and drift with the plankton.
-The tiny percent that survive and settle on the reef then begin new coral colonies.
Information Sources: Australian Marine Life, by G.J.EdgarSteve Parish: Amazing Facts about Australian Marine Life Encyclopedia Britannica and http://www.reef.crc.org.au/
-The Great Barrier Reef is relatively young at just 500,000 years old.
-The current reef's structure is much younger at less than around 8,000 years old.
-Most modern reefs are formed on hard surfaces in the ocean, such as a base of an old reef that died during a period when sea level was lower, or the edge of a rocky island.
-Some coral reefs form in the deep ocean and are called atolls.
-Atoll starts life as a fringing reef, then becomes more of a ring growing on the shrinking land-mass, until the land disappears and just the coral circle remains.
-In some other cases, the coral growth is unable to keep pace with the sinking island, and sunken dead reefs have also been found.
-It was until the mid-18th century that corals were recognized as animals, not plants as what people used to thought.
the corals size:
-The corals size are individual polyps range from 3 - 56 mm in diameter or height; while colony size varies from 75 mm -1500 mm (1.5 m) in width, height or in length.
-Coral polyps: Coral reefs consist of hundreds and thousands of soft-bodied, invertebrate animals, which have no backbone which are known as coral polyps.
-The individual polyp is radially symmetrical and has a tubular body with tentacles surrounding the mouth at the upper end.
-Each polyp’s body wall consists of two layers of cells, an outer layer called the ectoderm and an inner endoderm layer.
-A gelatinous material called mesogloea is found in between these two layers.
hard corals:
-Hard corals build reefs by growing atop the stony skeletons of previous coral colonies.
-It consist of limestone cases made by coral polyps extracting calcium from seawater.
-These limestone cases form a so-called house for the coral polyp, consisting of a floor, outer walls and a number of internal partitions.
-Inside corals’ clear outer tissues live microscopic algae, which transform sunlight into sugars through photosynthesis.
-The hosts help themselves to some of the sugars and gain some colour through photosynthsis.
-Hard corals form the backbone of the reef. Corals are remarkable creatures, they can form vast colonies and habitats.
reproduction of corals:
-Corals reproduce in two ways- asexually and sexually.
-Some corals divide to form new individuals, known as asexual reproduction.
-Sexual reproduction takes place as mass spawning, where polyps release millions of eggs and sperm.
-Polyps are either male or female or both male and female.
-After the eggs and sperm are released, they float to the surface.
-The fertilised eggs that escape predation by other animals hatch into larvae and drift with the plankton.
-The tiny percent that survive and settle on the reef then begin new coral colonies.
Information Sources: Australian Marine Life, by G.J.EdgarSteve Parish: Amazing Facts about Australian Marine Life Encyclopedia Britannica and http://www.reef.crc.org.au/
No comments:
Post a Comment