👉 The phanerozoic era, also known as the Precambrian or Paleozoic period, is a geological time frame that spans over 4.5 billion years from Earth's formation to about 3.8 billion years ago. This time period is characterized by major changes in the composition and structure of the Earth's crust, resulting in the formation of the first life forms on Earth. The phanerozoic era includes a variety of geological events that occurred during this time frame