The Geologic Time Scale is a system proposed by Arthur Holmes, that explains the development of living organisms, the physical features, and development of the Earth. In this time scale there are three eras of time. These eras include the Paleozoic, the Mesozoic, and the Cenozoic eras. Before these eras there was the Precambrian. Precambrian was the longest time before eras. The Geologic Time Scale is also referred to as the Time Span of Earth history.
Scientists created the Geologic Time Scale using data that they collected. They collected this data by dating each and every fossil the found and recording it. To date the rocks they used the law of Superposition. This rule states that the lower the rock layer the older it is. So this means the layers on the top are the newest and the youngest. Also scientists used absolute and relative age to determine the age of the rocks. After doing this process multiple times they made the Geologic Time Scale.
Scientists have many ways to determine when an era ends. It depends on the living organisms and how they have changed. Sometime an era ends with a mass extinction. For example the Mesozoic era. An era also ends if there is a major change in organisms.
Scientists created the Geologic Time Scale using data that they collected. They collected this data by dating each and every fossil the found and recording it. To date the rocks they used the law of Superposition. This rule states that the lower the rock layer the older it is. So this means the layers on the top are the newest and the youngest. Also scientists used absolute and relative age to determine the age of the rocks. After doing this process multiple times they made the Geologic Time Scale.
Scientists have many ways to determine when an era ends. It depends on the living organisms and how they have changed. Sometime an era ends with a mass extinction. For example the Mesozoic era. An era also ends if there is a major change in organisms.