Darwin from Descent of Man to Emotions Darwin from Descent of Man to Emotions Between 1868 and 1872, the life and work of Charles Darwin from "Descent of Man" to "Emotions" continued with aspects of his intended "Big Book" on evolution through natural selection. He had by then hurriedly published an "abstract" of this work as "On the Origin of Species" in 1859, and following the immediate reaction to Darwin's theory his earlier work included demonstrating the utility of the flowers of Orchids in directing insect pollination to achieve cross fertilisation, and a summing up of thirteen years of experiments in "The Variation of Animals and Plants
Emotion in animals as when rolling and rubbing. Therefore, purring can be generally considered as an indicator of "pleasure" in cats. Low pitched bleating in sheep has been associated with some positive-valence situations, as they are produced by males as an estrus female is approaching or by lactating mothers while licking and nursing their lambs. The argument that animals experience emotions is sometimes rejected due to a lack of evidence, and those who don't believe in the idea of animal intelligence, often argue that anthropomorphism plays a role in individuals' perspectives. Those who reject that animals have the capacity to experience emotion do