Table 1.

Common terms in microbial ecology

Term	Definition
Alternative stable state	Ecosystems capable of existing under different community structures while maintaining the same or equivalent functions
Assembly	The study of how ecological processes shape observed patterns in microbial communities
Community structure	The composition of taxa in a community including the number of species and their relative abundances
Disturbance	The cause of a change in community structure or function such as a cough or routine of antibiotics
Diversification	Generation of new genetic variation through horizontal gene transfer
Diversity	Variation observed in an ecosystem at taxonomic, phylogenetic, or functional levels
Functional redundancy	A characteristic of an organism where certain taxa contribute in equivalent ways to an ecosystem function
Historical contingency	The legacy effect of a microorganism from a previous point in time
Migration	Introduction of new taxa
Niche	A specific environmental condition that selects for specific organisms
Panmictic	Random mating within a potential breeding population (horizontal gene transfer)
Phylogenetic	A suite of analyses that takes into account the evolutionary history of a community as species are not easily defined in microorganisms
Resilience	Capacity to return to a previous state after a disturbance event
Resistance	Ability to not be affected by disturbance
Selection	The sorting of microbial taxa by environmental conditions (e.g., moisture or pH)
Spatial variation	Differences in community structure/function in three-dimensional space
Stochastic changes	Variation in community structure/function that cannot be explained
Succession	Gradual changes in community structure over time due to a changing environment
Taxonomy	Names of a species or group of species, often referred to as a “taxon,” plural “taxa”