Emotion in animals specialised form of Occam's razor used in ethology, in which he stated: Charles Darwin initially planned to include a chapter on emotion in "The Descent of Man" but as his ideas progressed they expanded into a book, "The Expression of the Emotions in Man and Animals". Darwin proposed that emotions are adaptive and serve a communicative and motivational function, and he stated three principles that are useful in understanding emotional expression: First, "The Principle of Serviceable Habits" takes a Lamarckian stance by suggesting that emotional expressions that are useful will be passed on to the offspring. Second, "The Principle of
The Man in a Case Man in a case" worked. The exact prototype of Belikov is unknown. Some contemporaries (including V.G. Bogoraz and M.P. Chekhov) considered that the teacher of Ancient Greek language and the inspector of the Taganrog gymnasium A.F. Dyakonov was a prototype of "the person in a case", others described the traits of character of Dyakonov disproving opinion of the first. So, P.P. Filevsky noted Dyakonov's generosity and wrote: "I positively claim that between "The man in a case" and A.F. Dyakonov there is nothing in common and no local color can be found in this work by A.P. Chekhov". The cost