Note: The "How Continental Configuration Affects O2" video that I mention at the end is currently membersonly, but will be coming out soon for everyone, don't worry ;)

Primary references:
Mills and Canfield, 2014: https://doi.org/10.1002/bies.201400101
Cole et al., 2020: https://doi.org/10.1111/gbi.12382
Sperling et al., 2022: https://doi.org/10.1086/721754
Supplementary references:
1. Cloud, 1976: https://pubs.geoscienceworld.org/pale...
2. Knoll & Carroll, 1999: https://doi.org/10.1126/science.284.5...
3. Knoll, 1992: DOI: 10.1007/9781489924278_3
4. Berkner & Marshall, 1965: https://doi.org/10.1175/15200469(196...
6. Ravaux et al., 2013: https://doi.org/10.1371/journal.pone....
7. Sperling & Stockey, 2018: https://doi.org/10.1093/icb/icy088
8. Brocks et al., 2017: https://doi. org/10.1038/nature23457
9. Sperling et al., 2015: https://doi.org/10.1146/annurevecols...
10. Schmidtko et al., 2017: https://www.nature.com/articles/natur...

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!)

In this video, I dive into the topic of what triggered animal evolution or as I called it here "animalution"! It's important to remember that although life evolved very early on Earth (as early as 3.5 to potentially ~4 billion years ago!), complex multicellular animals did not evolve until billions of years later. In fact, over 85 % of Earth's history had occurred before animals evolved around 600 million years ago. So why was there such a long delay between microbial life evolution and animal evolution? And what finally trigger animals to evolve? A rise in oxygen concentrations coincided with animal evolution temporally, but did oxygen cause animal evolution or just correlate with it? We used to think that low oxygen concentrations before ~600 million years ago may have prohibited animal evolution, but we have sinced found many examples of primitive animals with the ability to live in anaerobic or very low oxygen conditions. So we now lean toward the hypothesis that a variety of factors likely came together to prohibit animal evolution before 600 million years ago and then a perfect storm of changes in these factors occurred that triggered animal evolution at that point. I discuss all the potential factors involved in this 'storm' in this video. I hope you enjoy! ;)

0:00 Video Outline
1:01 Oxygen Control Hypothesis
2:38 Original Evidence for OCH
3:25 Correlation is Not Causation
5:00 O2 Threshold Required for Animals?
7:11 Role of Temperature?
8:19 Role of Primary Production?
9:54 Role of Ca & P Availability?
10:49 Role of Animals?
12:55 O2 Still Main Factor?
14:39 O2 Threshold for Diversity but Not Evolution
18:00 Flipped Evidence for OCH
18:36 Possible Scenarios
19:52 Significance of This Research
20:51 References & Related Videos

Hey there, Earth enthusiast! Check my favorite Earthfriendly 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
EcoFriendly Tote (great for grocery shopping!): https://shrsl.com/3cwfp
Reusable straws + cleaning brushes (my fav!): https://shrsl.com/3cwft
Ecofriendly 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!)

Nontextbook 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
Carbonneutral pencil bag: https://shrsl.com/3cvjv
Carbonneutral backpack: https://shrsl.com/3cvkc

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!