The Rewards of Cooperation

Bacteria are among the earliest evolved life on Earth. They have survived the vicissitudes of the ages through sense of community.

Bacteria and other microbes frequently live in multispecies biofilms, enjoying mutualistic relationships and co-evolution that succor fitness.

Co-evolution readily occurs among microbes as they altruistically share bits of genetic data (plasmids) which they have found helpful. Plasmid transmission is known as horizontal gene transfer.

As a metropolis, the biofilm defines spatial organization for member species and overall community functions. In multispecies biofilms, groups of a single species negotiate living quarters so that each species occupies a defined micro-site favoring its own growth.

Biofilms afford mass production of compounds needed for growth and defense of the colony with an efficiency that cannot be achieved by individuals, small groups, or even single-species biofilm cities. Danish microbiologist Søren Johannes Sørensen: “As opposed to both free-living cells and mono-species biofilms, cooperative advantages acquired when living within a mixed community may frequently result in ’emerging community properties’, such as enhanced biomass production, access to complex nutrient sources, stress resistance or pathogenicity acquisition.”

Søren Sørensen: “Bacteria organize themselves in a structured way, distribute work and even to help each other. Henry Ford may have thought that he had found something brilliant when he introduced the assembly line and worker specialization, but bacteria have been taking advantage of this strategy for a billion years.”

Multispecies biofilms are not all are harmonious living. Competition for limited resources, such as space and nutrients, is pervasive. But the microbes never lose sight that a diverse, vibrant community abets survival.

“In the classic Darwinian mindset, competition is the name of the game. The best suited survive and outcompete those less well suited. But when it comes to microorganisms like bacteria, the most cooperative ones survive,” Sørensen concluded.


Wenzheng Liu et al, “Deciphering links between bacterial interactions and spatial organization in multispecies biofilms,” The ISME Journal (27 August 2019).

Bacteria contradict Darwin: survival of the friendliest,” ScienceDaily (11 October 2019).