The Sea Slug Forum - Symbiosis, commensalism, mutualism and parasitism
Mutualism is a positive reciprocal relationship between two species. The relationship is obligate, meaning at least one of the species must be involved in Commensalism means that one species benefits from the relationship, but the other. Symbiotic Interactions in Disease: Definition, Theory & Examples. Symbiotic Relationship: Definition & Examples. Mutualistic Relationships. Symbiosis comes from two Greek words that mean "with" and "living. Commensalism is a type of relationship where one of the organisms benefits greatly from.
In this association one organism [the commensal] benefits, and the other [the host] is apparently unaffected. This description would also fit the relationship between a carnivore and its live prey and a herbivore and the plant it feeds on, especially if they are very specialized in the food they eat. We normally define parasites as orgamisms which cannot survive without their host and have special modifications to their body or their life cycle for this association.
Commensalism - Wikipedia
In many ways though, the difference between a lion eating a gazelle and a flea feeding on a dog, is a matter of relative size. Many sea slugs have evolved close relationships with other organisms.
The simplest associations are the many nudibranchs which are permanently found on, or close by, the organisms they feed on.
These in include dorids and their sponges, aeolids on their cnidarians, polycerids on their bryozoans. Here are a few particular examples: The photos at the top of this page show two crustaceans, a copepod and a shrimp, which live in close association with various nudibranchs.
They illustarte the many crustaceans which are often found to have close relationships to various sea slugs. In most cases we know nothing about the relationships, but they are generally referred to as 'commensals'. The copepods are small crustacea often found living on dorid nudibranchs.
They are easily recognised because their two large egg sacs look like a pair of large 'tails'.15 INCREDIBLE Mutual Animal Relationships
The fungal genus Aspergillus is capable of living under considerable environmental stress, and thus is capable of colonising the upper gastrointestinal tract where relatively few examples of the body's gut flora can survive due to highly acidic or alkaline conditions produced by gastric acid and digestive juices. While Aspergillus normally produces no symptoms, in individuals who are immunocompromised or suffering from existing conditions such as tuberculosisa condition called aspergillosis can occur, in which populations of Aspergillus grow out of control.
Symbiosis in the Forest
Staphylococcus aureusa common bacterial species, is known best for its numerous pathogenic strains that can cause numerous illnesses and conditions. However, many strains of S. Other Staphylococcus species including S.
Arguments[ edit ] Whether the relationship between humans and some types of gut flora is commensal or mutualistic is still unanswered. Some biologists argue that any close interaction between two organisms is unlikely to be completely neutral for either party, and that relationships identified as commensal are likely mutualistic or parasitic in a subtle way that has not been detected.
For example, epiphytes are "nutritional pirates" that may intercept substantial amounts of nutrients that would otherwise go to the host plant.
Similarly, phoretic mites may hinder their host by making flight more difficult, which may affect its aerial hunting ability or cause it to expend extra energy while carrying these passengers. Types[ edit ] Phoretic mites on a fly Pseudolynchia canariensis Like all ecological interactions, commensalisms vary in strength and duration from intimate, long-lived symbioses to brief, weak interactions through intermediaries. Phoresy[ edit ] Phoresy is one animal attached to another exclusively for transport, mainly arthropodsexamples of which are mites on insects such as beetlesflies or beespseudoscorpions on mammals  or beetles, and millipedes on birds.
Inquilinism[ edit ] Inquilinism: Tillandsia bourgaei growing on an oak tree in Mexico Inquilinism is the use of a second organism for permanent housing. Examples are epiphytic plants such as many orchids that grow on trees,  or birds that live in holes in trees.