BBC Supernatural, This is an extract from the episode that talks about extrasensory perceptions of plants and animals. In the study of plant physiology, plant perception is a term used to describe mechanisms by which plants recognize changes in the environment. Examples of stimuli which plants perceive and can react to include chemicals, gravity, light, moisture, infections, temperature, oxygen and carbon dioxide concentrations, parasite infestation, physical disruption, and touch. Plants have a variety of means to detect such stimuli and a variety of reaction responses or behaviors.