Pic­tures Con­sid­ered #59 by Roberto — Choanofla­gel­lates (en­dear­ingly re­ferred to as "choanos") are the clos­est liv­ing rel­a­tive of an­i­mals and as such they can pro­vide in­sights into the evo­lu­tion of an­i­mal mul­ti­cel­lu­lar­ity. In­ter­est­ingly, at least two choano de­vel­op­men­tal fea­tures are in­duced by bac­te­r­ial prod­ucts.