Second, which of the four major eras (Precambrian, Paleozoic, Mesozoic, Cenozoic) would you get rid of? Do you think humans would exist now without the era you chose?

Answer 1

If I had to choose one of the four major geological eras to "get rid of," I would select the Precambrian era. This era encompasses the vast majority of Earth's history, spanning from the planet's formation about 4.6 billion years ago to around 540 million years ago. It is during this time that the planet underwent significant geological and atmospheric changes, and it is also when the first simple life forms emerged.

Without the Precambrian era, Earth would not have the conditions or the life forms that set the stage for the subsequent eras. The development of the atmosphere, oceans, and the first multicellular organisms all occurred during this time. Consequently, without the Precambrian, the Paleozoic era, which marks a time of complex life forms and the eventual emergence of vertebrates and land plants, could not have existed.

In this context, humans would likely not exist as we know them today. The evolution of more complex life forms, including mammals and eventually primates, would have been drastically altered without the foundational changes and developments of the Precambrian. Thus, while it is an interesting thought experiment, the removal of the Precambrian era would fundamentally alter the trajectory of life on Earth, making human existence highly improbable.