STOP!!!!. MAJOR SPOILERS AHEAD. If you have not yet taken the short, 5-question quiz in the previous post's Intro portion of this series, please do so before continuing. No need to post your answers....unless you want to, but these posts are about challenging your current beliefs about the Earth and our place in it. Naturally you'd want to see what your current beliefs are before seeing if you were right or not.
Welcome back! So how do you think you did? We have a pretty smart bunch of regulars here, so I am confident you nailed it........but let's see. Questions 1, 2, 3, & 5 can be answered in a few simple sentences: There have been 5 generally accepted mass extinction events since life first appeared with each event rendering at least 60% of the known species at the time extinct.
Some events even eliminated as many as 96% of certain species, which was much more than the 76% loss during the well-known "dinosaur extinction". Each event was the result of a set of circumstances that 'changed the game' for the current organisms and their demise then provided an opportunity for a new wave of lifeforms to fill the void, adapted to the new environment. Life would then exploit every niche...........right up until the next big change that wiped them out. Sometimes these changes in the environment were catastrophic accidents, geological changes, and even the result of the by-products or "emissions" of the predominant life forms themselves.
And since there were several Periods between a sterile planet and today, some creatures, like the dimetrodon previously pictured, were able to avoid confrontations with T-Rexes merely by never having lived alongside them, separated not by topography but instead by 200 million years!
Question #4 is a different story and we will get more into our place in this long equation as this piece develops. But before we do that, let's take things as they actually played out............succintly..........but with enough detail to tell a lucid story. Next time: The Pre-Cambrian and beyond- life doesn't begin instantly, but once it gets going.............BOOM!!! (I'll even throw in some kinky captions, LOL)