PBS Member Stations rely on viewers like you. To support your local station, go to http://to.pbs.org/DonateEons ↓ More info below ↓ Blood is one of the most revolutionary features in our evolutionary history. Over hundreds of millions of years, the way in which blood does its job has changed over and over again. As a result, we animals have our familiar red blood. But also blue blood. And purple, and green, and even white. Thanks to Julio Lacerda, Lucas Lima, Franz Anthony of Studio 252mya for several illustrations throughout this episode. You can find more of their work here: https://252mya.com/ Produced for PBS Digital Studios. Super special thanks to the following Patreon patrons for helping make Eons possible: Katie Fichtner, Anthony Callaghan, Renzo Caimi Ordenes, John Vanek, Neil H. Gray, Marilyn Wolmart, Esmeralda Rupp-Spangle, Gregory Donovan, Ehit Dinesh Agarwal, الخليفي سلطان , Gabriel Cortez, Marcus Lejon, Robert Arévalo, Robert Hill, Kelby Reid, Todd Dittman, Betsy Radley, PS, Colin Sylvester, Philip Slingerland, Jose Garcia, Eric Vonk, Tony Wamsley, Henrik Peteri, Jonathan Wright, Jon Monteiro, James Bording, Brad Nicholls, Miles Chaston, Michael McClellan, Jeff Graham, Maria Humphrey, Nathan Paskett, Connor Jensen, Daisuke Goto, Hubert Rady, Yuntao Zhou, Gregory Kintz, Tyson Cleary, Chandler Bass, Maly Lor, Joao Ascensao, Tsee Lee, Sarah Fritts, Ruben Winter, Ron Harvey Jr, Jacob Gerke, Alex Yan If you'd like to support the channel, head over to http://patreon.com/eons and pledge for some cool rewards! Want to follow Eons elsewhere on the internet? Facebook - https://www.facebook.com/eonsshow Twitter - https://twitter.com/eonsshow Instagram - https://www.instagram.com/eonsshow/ References: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5378490/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3097462/ https://www.ncbi.nlm.nih.gov/pubmed/17120194 https://www.hindawi.com/journals/ijz/2009/301284/ https://www.sciencedirect.com/science/article/pii/S0012160612006343?via%3Dihub https://www2.estrellamountain.edu/faculty/farabee/biobk/BioBookcircSYS.html http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.456.5625&rep=rep1&type=pdf https://books.google.com/books?id=pKlVDwAAQBAJ&pg=PA35&lpg=PA35&dq=origin+of+blood+triploblasts&source=bl&ots=OofsZKI3SN&sig=I6Y92wODJah2vWgtPShcnPtR5eI&hl=en&sa=X&ved=2ahUKEwjZ5Lmz6NveAhVPslMKHdOeCSoQ6AEwDXoECAMQAQ#v=onepage&q=origin%20of%20blood%20triploblasts&f=false http://thebiologyprimer.com/the-origin-and-evolution-of-animals/ https://www.researchgate.net/profile/Thorsten_Burmester/publication/11448732_Origin_and_evolution_of_arthropod_hemocyanins_and_related_proteins/links/558c352e08ae1f30aa809ad6.pdf https://courses.lumenlearning.com/wm-biology2/chapter/circulatory-system-variation-in-animals/ http://jeb.biologists.org/content/jexbio/201/8/1099.full.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3543078/ https://www.physiology.org/doi/full/10.1152/physrev.2001.81.2.569?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed https://www.britannica.com/science/circulatory-system/The-vertebrate-circulatory-system http://www.nhm.ac.uk/discover/news/2014/april/earliest-heart-blood-discovered.html https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2614223/ https://www.nature.com/articles/ncomms4560 https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1502-3931.1997.tb00458.x http://www.nrcresearchpress.com/doi/10.1139/e06-012 https://www.britannica.com/animal/mollusk#ref35787 https://www.forbes.com/sites/shaenamontanari/2016/04/20/oldest-example-of-a-chambered-heart-found-in-a-113-million-year-old-fossil/#468a52b026d4 https://www.sciencedirect.com/science/article/pii/S1570963913000836 https://www.jstor.org/stable/30158158?seq=3#metadata_info_tab_contents http://www.sci-news.com/paleontology/science-fossil-oldest-known-cardiovascular-system-01839.html https://academic.oup.com/icb/article/55/5/792/604091 https://www.mdpi.com/2308-3425/2/1/2/pdf