A comment on my recent Mesozoic marine reptiles video brought up a great question... Where the heck were sharks at that time? Which brought up additional questions like: where were sharks throughout the entirety of Earth history? When did sharks evolve? What were early sharks like? Were there other animals that ate sharks in Earth history? And if so, when did sharks become the ultimate apex predators of the sea??? In this video, I go through the surprisingly LONG evolutionary history of sharks! Sharks have been around for almost 450 million years! Throughout this time they've made some amazing (and some really bizarre) evolutionary adaptations. So, I hope you enjoy learning about the history of sharks with me! ;)

References:
Earth System History: https://amzn.to/3v1Iy0G
Emma Bernard, curator of fossil fish at Natural History Museum: https://www.nhm.ac.uk/discover/shark-...

0:00 Inspiration for video
0:50 First fish (~530 Ma)
2:12 Armored fish (~500 Ma)
3:14 Jawed fish (~430 Ma)
4:40 First sharks (~420 Ma)
5:53 Sharks vs other predators (~400 Ma)
6:51 Devonian extinctions
7:59 Age of sharks (~350 Ma)
10:12 Life on land (~350 Ma)
11:22 Jurassic sharks (~200 Ma)
13:11 Sharks vs sea monsters
14:40 Dinosaur extinction event
16:17 Megalodon
17:04 Modern sharks
17:36 How they lasted 450 million yrs!

GEO GIRL Website: https://www.geogirlscience.com/ (visit my website to see all my courses, shop merch, learn more about me, & donate to support the channel if you'd like!)

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Bamboo toilet paper: https://shrsl.com/3cvku
Bamboo paper towels: https://shrsl.com/3cvkw
Compostable tableware: https://shrsl.com/3cvkz
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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

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!