Producer/Host: Sarah O’Malley This episode discusses the origins of mucus in early animal lineages, including Cnidaria and Ctenophora, and highlights the lack of mucus in another early animal lineage, Porifera (sponges). Scientists hypothesize that the invention of mucus was a major event that enabled the evolution of true tissues, as well as serving as the front line of the immune system, separating microbes from vulnerable tissue, in all animals from Cnidarians to ourselves. About the host: Sarah O’Malley is an ecologist, naturalist and science communicator passionate about deepening her listeners’ experiences with the natural world. She teaches biology and sustainability at Maine Maritime Academy and is currently collaborating on a guide book to the intertidal zone in the Gulf of Maine.