Commensalism

Definition

Commensalism is a type of symbiotic relationship where one organism benefits while the other is neither helped nor harmed. This relationship often occurs between different species of prokaryotes in diverse habitats.

5 Must Know Facts For Your Next Test

1. In commensalism, the commensal organism derives some benefit, such as nutrients or shelter, without affecting the host organism.
2. Commensal relationships are common in microbiomes, particularly in human and animal bodies where many bacteria live without causing harm.
3. An example of commensalism is the relationship between Staphylococcus epidermidis and human skin; the bacteria benefit from nutrients on the skin but do not harm their host.
4. Commensal organisms can sometimes turn into opportunistic pathogens if the host's immune system is compromised.
5. Understanding commensalism helps microbiologists study how microbial communities interact within various environments.

Review Questions

• What is commensalism and how does it differ from mutualism?
• Give an example of a commensal relationship involving prokaryotes.
• Why is it important to study commensal relationships in microbiomes?

Related terms

Mutualism:

A symbiotic relationship where both organisms involved benefit.

Parasitism: A symbiotic relationship where one organism benefits at the expense of the other.

Microbiome:

The community of microorganisms living together in a particular habitat.