Final answer:
The four geological time eras from the oldest to newest are the Paleozoic, Mesozoic, Cenozoic, and the current Phanerozoic era, with each era marked by distinctive life forms and geological changes.
Step-by-step explanation:
The four geological time eras in order from the first to the most recent are Paleozoic, Mesozoic, Cenozoic, and the current Phanerozoic era. These eras are part of the Phanerozoic eon, the most recent of the three major divisions of Earth's history before the current Quaternary period. Each era is characterized by distinct developments in life forms and significant geological events. The Paleozoic era saw the emergence of marine life and the first vertebrates, the Mesozoic era is often called the Age of Reptiles, the Cenozoic era is characterized by the dominance of mammals, and the Phanerozoic encompasses complex life.
These eras are part of the geologic time scale, which is divided into eons, eras, periods, epochs, and ages. The Quaternary era is the most recent and is characterized by the Ice Age and the emergence of modern humans. The Jurassic era is known for the dominance of dinosaurs. The Cretaceous era is marked by the extinction of the dinosaurs. The Tertiary era follows the extinction and is when mammals began to flourish.