A new research has revealed one of these reefs located on dry land in Namibia was built almost 550 million years ago by the first animals to have hard shells.
The creatures known as Cloudina built reefs in ancient seas that now form part of Namibia. Their fossilized remains are the oldest reefs of their type in the world.
Scientists established that it was at this point that tiny aquatic creatures developed the ability to construct hard protective coats and build reefs to shelter and protect them in an increasingly dangerous world. The animals attached themselves to fixed surfaces and to each other by producing natural cement composed of calcium carbonate, to form rigid structures.
Researchers also revealed that the development of hard biological structures through a process called biomineralisation sparked a dramatic increase in the biodiversity of marine ecosystems.
Professor Rachel Wood, Professor of Carbonate GeoScience at the University of Edinburgh said that they have found that animals were building reefs even before the evolution of complex animal life, suggesting that there must have been selective pressures in the Precambrian Period that are yet to be understood.
The study is published in the journal Science.