Symbiosis is any type of a close and long-term biological interaction between two biological organisms of different species, termed symbionts, be it mutualistic, commensalistic, or parasitic. In 1879, Heinrich Anton de Bary defined it as "the living together of unlike organisms". The term is sometimes used in the more restricted sense of a mutually beneficial interaction in which both symbionts contribute to each other's support.
In a cleaning symbiosis, the clownfish feeds on small invertebrates, that otherwise have potential to harm the sea anemone, and the fecal matter from the clownfish provides nutrients to the sea anemone. The clownfish is protected from predators by the anemone's stinging cells, to which the clownfish is immune. The relationship is therefore classified as mutualistic.
Alder tree root nodule houses endosymbiotic nitrogen-fixing bacteria.
Hermit crab, Calcinus laevimanus, with sea anemone
Bryoliths document a mutualistic symbiosis between a hermit crab and encrusting bryozoans.
In ecology, a biological interaction is the effect that a pair of organisms living together in a community have on each other. They can be either of the same species, or of different species. These effects may be short-term, or long-term, both often strongly influence the adaptation and evolution of the species involved. Biological interactions range from mutualism, beneficial to both partners, to competition, harmful to both partners. Interactions can be direct when physical contact is established or indirect, through intermediaries such as shared resources, territories, ecological services, metabolic waste, toxins or growth inhibitors. This type of relationship can be shown by net effect based on individual effects on both organisms arising out of relationship.
The black walnut secretes a chemical from its roots that harms neighboring plants, an example of competitive antagonism.
Predation is a short-term interaction, in which the predator, here an osprey, kills and eats its prey.
Pollination has driven the coevolution of flowering plants and their animal pollinators for over 100 million years.
Male-male interference competition in red deer
