Eyewire Rocks: Mesozoic vs. Cenozoic

The science of geology has been instrumental for humankind to learn about the history of Earth, from how our planet was formed to how the world’s continents reached their current positions. But while we often think “geology = rocks,” geology doesn’t strictly concern itself with mineral matter. It’s a field where some researchers can heavily focus on organic fossil records, overlapping with paleontologists. Living things leave their own mark on the composition of our air, water, and soil, which then influences the chemical makeup of the layers of bedrock beneath us. And in turn, we can find evidence in the Earth’s crust of those living things, whether through decomposed sediment or through whole fossilized bones.

In fact, the status of life on Earth typically forms the basis of how geologists differentiate certain time frames. Take the two most recent geological eras: the Mesozoic, which means “middle life,” and the Cenozoic, which means “recent life.” These eras are distinguished by fossil records, which include animals, plants, and other life forms of all shapes and sizes. But surely what most people know of those records is each era’s megafauna— giant animals!

Mesozoic Era

• Dinosaurs, dinosaurs, dinosaurs! Who doesn’t love them, as well as other giant reptiles? (Shout out to pterodactyls.) We can find fossil evidence of these stompers and chompers anywhere from 252 million to 66 million years ago.
• This era is further divided into the Triassic, Jurassic, and Cretaceous Periods. Over these periods, the supercontinent Pangaea split into the two continents of Laurasia and Gondwana; in turn, those continents split into the smaller ones we have today, but they were still in different positions.
• While popular imagination does call this the Age of Reptiles, it was also the Age of Conifers. Cone-bearing trees and bushes were eeeeverywhere, and you would never have even seen a flowering plant until the early Cretaceous!

Cenozoic Era

• The extinction of the dinosaurs 65 million years ago paved the way for other huge critters to take their place, and these ones were a lot fuzzier. We’re talking sabre-toothed cats, mammoths, giant sloths, and dire wolves!
• This era is further divided into the Paleogene, Neogene, and Quaternary Periods. Human beings evolved during the Quaternary, which continues today but began much icier. Huge glaciers of various Ice Ages have carved up the bedrock of millennia past.
• Many call this the Age of Mammals, but we also can’t write off the enormous birds that ruled the land during the Paleogene. Some bird species were three meters tall!

Which of these prehistoric lineups is your #squadgoals? Which life forms and tectonic arrangements would be your preference? Eyewire’s going to have a megafauna faceoff that starts at 11:00 AM EST on 2/24 and goes for 48 hours! Remember that we have a new VS scoring system, with bonuses detailed in your notifications!

Swag (generously sponsored by @susi): The top scoring player on the winning team wins 1 tote bag! Also, among the top 50% of players on the winning team, 1 player will be raffled 1 notebook, and 3 more players will be raffled the choice of sticker or magnet.

Artwork by Daniela Gamba