Recurring Guest Characters Salman Rushdie 1 guest appearances Mae Jemison 1 guest appearances Godfrey 1 guest appearances Lawrence Krauss 1 guest appearances Ronke Olabisi 1 guest appearances Neuroscientist 1 guest appearances Lance Armstrong 1 guest appearances Kareem Abdul-Jabbar 1 guest appearances Jane Goodall 1 guest appearances Biological Anthropologist 1 guest appearances Katie Couric 1 guest appearances Katy Perry 1 guest appearances Alan Alda 1 guest appearances Frank Oz 1 guest appearances Stephen Colbert 1 guest appearances Andy Serkis 1 guest appearances Biomedical Scientist 1 guest appearances Michio Kaku 1 guest appearances Stephen Hawking 1 guest appearances Yvette d'Entremont 1 guest appearances ⇤ « 1 2 3 4 5 » ⇥