The momentous transition to multicellular life may not have been so hard after all

Single cells had many of the genes and functions needed for complex life to evolve. Learn more: Credits: producer/editor/script/narrator Nguyen Khoi Nguyen supervising producer Sarah Crespi original story Elizabeth Pennisi graphics collar cells The Biology of Marine Animals young sponge The Cambridge Natural History multicellular yeast V. Altounian/Science photography choanoflagellates (2) Mark Dayel, crepidula fornicata Joyce Pieretti, Manuela Truebano, Saori Tani, and Daniela Di Bella/ Embryology Course at the Marine Biological Laboratory adult amphipod Longhua Guo/ Embryology Course at the Marine Biological Laboratory juvenile of the longfin inshore squid Wang Chi Lau/ Embryology Course at the Marine Biological Laboratory veiled chameleon Jake Hines and Nate Peters/ Embryology Course at the Marine Biological Laboratory chlamydomonas globosa Picturepest, , CC BY 2.0 volvocales Aurora M. Nedelcu, , CC BY 2.5 gonium pectorale Environmental Protection Agency , public domain volvox aureus Zappys Technology Solutions , CC BY 2.0 volvox aureus Picturepest, , CC BY 2.0 yeast Marina Taikevich, , CC BY 2.0 saccharomyces cerevisiae Pilarbini, , CC BY 4.0 video squid development April Dinwiddie, Jenna Judge, Lynn See, Rachel K. Miller, Marie-Therese Noedl, Juliette Petersen, Maggie Rigney, Ju Roscito, Brittany Shamenek, and Nipam Patel yeast snowflake confocal Ozan Bozdag, Siyi Cao, Ali Zamani and Will Ratcliff multicellular yeast time-lapse Will Ratcliff multicellular chlamydomonas time-lapse Matthew Herron, Joshua Borin, and Will Ratcliff developing embryos of the African clawed frog Nipam Patel, Chenbei Chang/ Embryology Course at the Marine Biological Laboratory stock video Videoblocks music Nguyen Khoi Nguyen