Modern humans haven’t been on the planet for all that long, and written history of our ancestors are limited by the appearance of the first writing systems only 5,300 years ago. Prior to that, our ancestors had inhabited the Earth for slightly over 3.3 million years, a time that saw us progress from using stone tools and being nomads, to settling down and forming a society and several civilizations.
Depending on the use of the word, prehistory itself can be used to describe the entire time since the beginning of the Universe or the creation of Earth. That being said, it is often used to refer to the period of time since life appeared on Earth, or more specifically to the arrival of the first humans over 4 million years ago. As aforementioned, the advent of written history only happened relatively late in our own evolution, so other than carbon dating, cave paintings and accounts of previous generations is all we have to go by.
However, from a geological and scientific standpoint there is a lot to discuss and dissect. Most of the major geological changes that defined our world happened prior to the appearance of the first man, with millions of years of movement, environmental changes and evolution leading to that point. Scientists have separated these time periods into distinctive blocks that define different parts of the Earth’s prehistory, all of which saw an important event.
For example, the Cambrian Explosion during the Cambrian Period (541 million years ago) saw an enormous uptick in the creation of new species and bacteria that would become modern-day animals. That same Era saw the creation of the ozone layer and the branching out and diversification of life. There were several other periods, all with their own landmark event.
Human development periods have also been defined, with most people acquainted with at least a couple of them (Stone, Bronze and Iron Ages all happened in the past 3.3 million years). Although a touch odd, the insanely informative viral video uploaded by YouTuber Bill Wurtz has a very good condensed summary of everything that led to where we are now. The aptly named “History of the entire world I guess” has been seen by over 28 million people since its original upload in May 2017, and despite the use of some harsh language it has been lauded as a great educational video.