Question

Explain the following term:

Geological time scale

Answer 1

The Geological Time Scale is a system used by geologists and paleontologists to organize and divide Earth’s history into different time periods based on geological and paleontological evidence.

1. It covers the entire span of Earth’s history, from its formation about 3800 million years ago to the present.
2. The Geological Time Scale is divided hierarchically into five major eras: Archaeozoic, Proterozoic, Palaeozoic, Mesozoic, and Cenozoic.
3. Each era is further subdivided into periods, and each period can be further subdivided into epochs.
4. These divisions are based on significant events such as major climatic changes, appearance or extinction of important plant and animal groups, and geological phenomena like mountain formation.
5. For example, the Mesozoic era is known as the “Age of Reptiles” and includes the Jurassic period, famous for dinosaurs.
6. The Cenozoic era is known as the “Age of Mammals” and includes the Quaternary period, which encompasses the rise of modern humans.
7. Radiometric dating and fossil evidence are used to assign approximate ages to these time units.