Humans communicate with each other in order to exchange information. We can do this in several ways, either verbally, in written form or through body movements. What is not generally known is that plants and animals also have their means of communicating with each other. It is legitimate to call this communication, since two or more living beings transmit information as senders and receivers.
When it comes to plants, communication can take place inside cells, between cells, between plants belonging to the same or a similar species, and between plants an non-plant organisms. For example, the roots of a plant can contact bacteria, fungi and insects that live in the soil. Plant communication even has syntactic, semantic and pragmatic rules and is made possible by the special nervous system of plants which is decentralised. It works on a neural basis but also through volatiles.
In the fungi kingdom, communication is used to control growth and development. Like other living organisms, also fungi can communicate within their own or related species as well as with non-fungal organisms, especially plants, insects, bacteria and other microorganisms. The fungal system of communication is triggered by molecules.
Animals have a wide range of communication methods. Generally speaking, communication between animals can be defined as the behaviour portrayed by one animal which influences the current or future behaviour of another. Even rather primitive creatures, for example corals, can communicate with each other. The scientific field that researches communication between animals is called zoosemiotics and research in the area, as well as in other animal-related scientific fields, is increasing quickly. There are differences between communication inside one species and communication between distinct species, such as predator and prey or animal and human. Forms of communication include gestures, facial expressions, use of scent, gazing, vocalisation, bioluminescence and electrocommunication.
Even as small a living organism as bacteria use means of communication: The so-called quorum sensing is a method where the density of cells can be identified. The bacteria regulate their gene expression differently according to how dense the cells are. The scientists found the phenomenon when investigating marine microorganisms. Quorum sensing is used by gram positive bacteria as well as by gram negative bacteria.