Which of the following provides molecular evidence that signal transduction pathways evolved early in the history of life? cell signaling is observed in organisms that do not utilize sexual reproduction. the pathways in primitive organisms, such as bacteria, are short, whereas those in advanced forms, such as mammals, are long. receptor molecules have been identified in preparations of fossilized organisms billions of years old. the molecular details of cell signaling are quite similar in organisms whose last common ancestor was a billion years ago. simple forms of life, such as prokaryotic cells, utilize cell signaling.