What Was Earth Like Before Dinosaurs?

[Narrator] It's common knowledge that dinosaurs come to mind when we consider the millions of years ago, or long before recorded history, right? Yes, those big boys are awesome, but before the first dinosaurs appeared on the scene, life on Earth existed for billions of years. However, it wasn't at all what you might have thought. So join me as I take you on an exciting voyage starting from the very beginning of Earth and ending with the emergence of the dinosaurs. (Soft music) It's wise to begin at the beginning, as with most things. Massive space rocks that are hundreds of miles across were formed when gas and dust leftover from the Sun's formation clumped together some 4.6 billion years ago. I apologize for the extreme simplification, but these ran into each other.

repeatedly and finally fused to form the Earth, though it's unquestionably not the Earth that you or I are familiar with. No, the early Earth was a molten, radioactive, and horrifying place with frequent impacts from asteroids and extremely hot lava. That concluded things. Forever, forever, forever. Things wouldn't get interesting until approximately 3.7 billion years ago, or nearly a billion years later. Our planet had cooled considerably by this point, approaching modern temperatures. However, that does not imply that it was friendly. It was an empty world of raging seas and rocky crags, mostly made of water with an atmosphere mostly devoid of oxygen. You would have heard nothing but the unceasing crash of the tide hitting the beach. That

as well as the sporadic eruption of volcanoes. It's so eerie, huh? However, something astounding and completely puzzling occurred deep within the waters of this eerie location. The beginning of life. We don't know exactly how, but some sort of miraculous combination of conditions in the Earth's oceans produced incredibly basic, unicellular organisms. And a few of these creatures were oxygen producers. Our single-celled friends were free to roam around, absorbing nutrients and ejecting waste products from their bodies, for billions of years. What a life it is. But they started to evolve and become more complicated very gradually.

The culmination of this would occur approximately 538 million years ago, at the onset of the Cambrian period. Rodinia was the name of the single supercontinent that the Earth's landmass had before the Cambrian. As the

Nevertheless, the Cambrian period saw the division of this into multiple smaller landmasses, the largest of which was Gondwana in the southeast. However, that isn't the thrilling part. Give me to introduce you to the greatest event in the history of our blue planet's biodiversification: the Cambrian explosion. Now, by explosion, I do not mean a loud, violent bang. No, this explosion was more of a metaphor for the sheer quantity of new species that appeared. The days of single cells were long ago. Complex lives were trendy right now. During this period, the majority of the basic body forms that we see today first emerged, and under the waves, relatives of mollusks, starfish, worms, and crustaceans developed. Don't get me wrong, there was still an explosion.

over tens of millions of years, but this was a significant event given the poor evolution in the billions of years prior. Regarding the cause of the Cambrian explosion, scientists are still at odds. But don't forget that some of those first, simple organisms began to produce oxygen. One theory is that they multiplied quickly, significantly raising oxygen levels and paving the way for the emergence of more complex life forms. Now, where were we? Ah, yes, the Cambrian period.