A type of mutualism in which the interacting species derive benefit from each other but not being fully dependent that each cannot survive without the symbiotic partner.
In facultative mutualism both species benefit from the relationship, but can live without it. For example, humans and cats enjoy a facultative mutualistic relationship. People gain companionship, pest control, and some health benefits from having a cat. But, people can live without cats.
While mutualism is highly complex, it can be roughly broken down into two types of relationship. In some cases, the species are entirely dependent on each other (obligate mutualism) and in others, they derive benefits from their relationship but could survive without each other (facultative mutualism).
Obligate symbiosis suggests that at least one of the partners cannot complete its lifecycle on its own while facultative symbiosis suggests that partners do not necessarily require one another to survive and/or reproduce.
A mutualism is obligate when one species relies completely on another species for goods or services. Yucca moths and yucca plants have a reciprocal obligate relationship- the plants cannot make seeds without the yucca moth, and the moth larvae only reach maturity if they eat developing yucca seeds (Pellmyr 2003).
Relationships can be obligate, meaning that one or both of the symbionts entirely depend on each other for survival. For example, in lichens, which consist of fungal and photosynthetic symbionts, the fungal partners cannot live on their own.
An obligation refers to a relationship of rights and obligations for which specific parties can claim specific performance. . In an obligatory relationship, the obligee shall be the party who has the right while obligor shall be the other party who bears the obligation.
The most common examples of the facultative anaerobes are bacteria (e.g., Escherichia coli, Pseudomonas aeruginosa, Staphylococcus spp., Listeria spp., Salmonella, Shewanella oneidensis, and Yersinia pestis), Archaea, certain eukaryotes (e.g., Saccharomyces cerevisiae) and invertebrates, like nereid and polychaetes.
Facultative Parasites
They live freely and infect the host rarely in their life span. Examples of facultative parasites are candida, acanthamoeba, etc. Certain fungi exist as facultative parasites but also as saprophytes when they are not infecting the host.
Scientific definitions for facultative
facultative. [ făk′əl-tā′tĭv ] Capable of existing under varying environmental conditions or by assuming various behaviors. Bacteria that are facultative aerobes can live in both aerobic and anaerobic environments. A facultative parasite can live independently of its usual host.
For example, a plant that cannot produce seeds in the absence of a single pollinator species is engaged in a species-specific, obligate mutualism, while a plant that can self-pollinate to some extent and that can be pollinated by multiple flower-visitors is involved in a facultative, generalized mutualism.
Investigators have distinguished between obligate and facultative mutualism. In obligate mutualism, two organisms in a mutualistic association are dependent on each other for survival. In facultative mutualism, two organisms benefit from each other but are not dependent on their mutualistic association for survival.
Facultative anaerobe gathers mostly at the top of the culture tube and also spreads throughout the culture medium. Some examples of obligate anaerobes are Actinomyces, Bacteroides, Clostridium, Fusobacterium, Peptostreptococcus, Porphyromonas, Prevotella,Propionibacterium, and Veillonella.
Facultative symbiosis is when the species live together by choice. There are four main types of symbiotic relationships: mutualism, commensalism, parasitism and competition.
(1) Not compulsory; not restricting. (2) Of, or relating to, mental faculty. (biology) Capable of existing to more than one set of (environmental) conditions or by assuming various behaviors.
Definition. The word “facultative” originated from the New Latin word facultātīvus which means “optional,” the process in which an organism could perform optionally in response to a particular situation rather than by nature (http://www.dictionary.com/browse/facultative).
An organism that can not complete its life cycle without its host is called obligate parasite. They cannot live without host. A facultative parasite is an organism that may resort to parasitic activity, but does not absolutely rely on any host for completion of its life cycle. It is not completely dependent on host.
A facultative parasite is organism that is normally saprophytic but is capable of being parasitic.
Some bacteria are obligate parasites and grow only within a living host cell. Rickettsia and Chlamydia, for example, grow in eukaryotic cells, and Bdellovibrio grow in bacterial cells.
Red maple, Poison ivy, Switchgrass, and Alpine violet are examples of facultative plants.
Plants with a facultative response flower faster under a particular photoperiod but will eventually flower under all photoperiods. For example, a facultative short day plant will flower faster under short days but will eventually flower under long days as well (Figure 1).
The last questions in the examination were facultative. 3. A facultative pathogen of some insect species commonly used as a biopesticide.
This can be broken into obligatory mutualism, where one species cannot survive without the other species, and facultative mutualism, where one species could survive without the other species, but it is better for both species to maintain the relationship.
Obligate Mutualism
In obligate mutualism the relationship between two species, in which both are completely dependent on each other. Most of the symbioses and some non-symbiotic are the best examples of obligate mutualism. For example Yucca plant and the moth.
Definition. noun. A type of mutualism in which the species involved are in close proximity and interdependent with one another in a way that one cannot survive without the other.