A new study suggests that shells and skeletons came into the world just 550 million years ago. They were a result of change in chemical make-up of seawater.
Studies say that ancient marine life may have started with animals which had soft bodies. They later would have developed with hard body parts due to an increase in level of calcium and magnesium levels in the ocean. Up till now not much is known about the evolution of skeletons and shells. It is being said that the soft bodied animals must have gone under mass extinction which supported the skeleton and shell having organisms to flourish. However, some researchers contradict this point and believe that the soft bodied and hard bodied organisms co-existed during the earliest stages.
Researchers have always considered that how animals to produced skeletons and shells is a major event in the history of evolution. This theory can provide further insight into the area and can help in understanding the processes of the evolution.