Ethos takes account of the character, sentiment, manners, moral nature, or guiding beliefs of a person, group, or institution and the predominant characteristics of a racial culture. In rhetoric, this is the speakers' or writer's character or emotions, articulated in the attempt to persuade an audience. Ethos is distinguished from pathos, which is the emotion the speaker or writer hopes to induce in the audience. The two concepts were well known in a broader sense by ancient Classical authors, who used pathos when referring to the violent emotions and ethos to mean the calmer ones. Ethology deals with the behaviour in a natural environment and investigates the development of systems of morals; now more generally, the science of human character. Ethology is particularly concerned with the animal's interactions with others of the same species and the function of behaviour and how the evolution of behaviour has been influenced by natural selection.