Cambrian Explosion- More like PREcambrian Explosion & Cambrian Skeletonization | GEO GIRL

Does the term 'Cambrian Explosion' still hold up? Was it really an 'explosion' of life? We've learned a lot since naming the Cambrian Explosion, such as the fact that animals not only existed but became quite complex before the Cambrian. We now know that Ediacaran Fauna (animals that characterize the Ediacaran period just before the Cambrian boundary) as well as early representatives of major animal groups on modern Earth predate the Cambrian boundary. However, the evolution of the latter may have contributed to the extinction of the Ediacaran Fauna. However, we don't yet know whether it was abiotic climate and environmental changes or biological competition and predation that caused the Ediacaran mass extinction. All we know for sure is that the extinction of these early 'experimental' animals paved the way for the evolution of the modern animal groups. Ediacaran and Cambrian fauna differ in many ways, but the major differences were the larger size and greater abudance & complexity of shells and skeletons in Cambrian animals. Cambrian fauna was also much more diverse than Ediacaran fauna with many more animal phyla evolving in the Cambrian compared to the lonely soft bodied corals, jellies, and sponges of the Ediacaran. However, some of the major reef building organisms in the Cambrian underwent mysterious extinctions throughout the period, suggesting that the trend of experimental evolution & abrupt extinction of certain animal groups was not over. So what was the major cause of the Cambrian Explosion (or the increase in diversity, complexity, and skeletonization in the Pre- and Early Cambrian)? Likely, increased oxygen concentrations [O2]. However, other factors, like increased predation and calcium & phosphate flux to the ocean also contributed to increased skeletonization in benthic animals. References: Geomicrobiology: https://amzn.to/2WAloTR Earth System History: https://amzn.to/3v1Iy0G (1) https://doi.org/10.1016/j.tree.2018.0... (2) https://doi.org/10.1126/sciadv.aan8983 (3) https://doi.org/10.1098/rspb.2015.1003 (4) https://doi.org/10.1038%2Fnature07072 GEO GIRL Website: https://www.geogirlscience.com/ (visit my website to see all my courses, shop merch, learn more about me, and donate to support the channel if you'd like!) Studying for an exam? Schedule Tutoring with me: https://GEOGIRLTutoring.as.me/ Hey there, Earth enthusiast! Check my favorite Earth-friendly products: Bamboo toilet paper: https://shrsl.com/3cvku Bamboo paper towels: https://shrsl.com/3cvkw Compostable tableware: https://shrsl.com/3cvkz Compostable trash bags: https://shrsl.com/3cvl0 Bamboo cutlery + straw! : https://shrsl.com/3cwfl Eco-Friendly Tote (great for grocery shopping!): https://shrsl.com/3cwfp Reusable straws + cleaning brushes (my fav!): https://shrsl.com/3cwft Eco-friendly laundry detergent: https://shrsl.com/3cwgo Directly offset your carbon footprint with Wren: https://shrsl.com/3d0t2 (Just click link, press get started, take the free C footprint quiz, then choose how much you want to reduce your footprint by donating to the C sequestration projects they're funding!) Non-textbook books I recommend: Oxygen by D. Canfield: https://amzn.to/3gffbCL Brief history of Earth by A. Knoll: https://amzn.to/3w3hC1I Life on young planet by A. Knoll: https://amzn.to/2RBMpny Some assembly required by N. Shubin: https://amzn.to/3w1Ezm2 Your inner fish by N. Shubin: https://amzn.to/3cpw3Wb Oxygen by N. Lane: https://amzn.to/3z4FgwZ Alien Oceans by K. Hand: https://amzn.to/3clMx1l Life's Engines: https://amzn.to/3w1Nhke Tools I use as a geologist/teacher/student: Geology field notebook: https://amzn.to/3lb6dJf Geology rock hammer: https://amzn.to/3DZw8MA Geological compass: https://amzn.to/3hfbdLu Geological hand lens: https://amzn.to/3jXysM5 Camera: https://amzn.to/3l6fGRT Carbon-neutral pencil bag: https://shrsl.com/3cvjv Carbon-neutral backpack: https://shrsl.com/3cvkc 0:00 Was it really an Explosion? 1:45 Since Naming the Cambrian Explosion… 4:06 Ediacaran Fauna 5:39 Major Animal Groups Predate Cambrian 6:26 Mass Extinction of Ediacaran Fauna 7:32 What Caused Ediacaran Extinction? 9:18 Patchy Fossil Record Makes it Difficult… 11:27 Ediacaran vs Cambrian Fauna 15:05 New Cambrian Life 17:26 Huge Cambrian Predators 18:01 Mysterious Cambrian Extinctions 19:36 Major Cause of Cambrian Explosion 20:43 Why Low Diversity for First 4 ~Billion Yrs on Earth? 23:38 Why High Diversity After ~600 Ma? 25:55 What Caused O2 increase ~600 Ma? 27:10 Summary of Ediacaran to Cambrian Events 28:08 Related Videos & References Disclaimer: Links included in this description might be affiliate links. If you purchase a product or service with the links that I provide I may receive a small commission, but there is no additional charge to you! Thank you for supporting my channel so I can continue to provide you with free content each week! And as always, let me know your topic suggestions in the comments down below!