The correct order of the geologic timescale from oldest to most recent is:

1. Precambrian (4.5 billion years ago to 541 million years ago) - This is the longest eon, encompassing the formation of Earth and the earliest life.

2. Paleozoic (541 million years ago to 252 million years ago) - This era saw the rise of diverse marine life, the first land plants, and the first vertebrates.

3. Mesozoic (252 million years ago to 66 million years ago) - This era is known for the rise of dinosaurs, the first mammals, and the break-up of Pangaea.

4. Cenozoic (66 million years ago to present) - This era saw the rise of mammals, the evolution of humans, and the development of modern ecosystems.

Within each era, there are periods, which are further subdivided into epochs.

Here's a simple mnemonic to remember the eras: PPC (Precambrian, Paleozoic, Cenozoic) with Mesozoic sandwiched in the middle.