Natural selection imitates a highly competitive economy – then everybody dies

December 21, 2020

We typically expect natural selection to improve the condition of a species, leading to their long-term survival; however, 99.9 percent of all species on Earth are now extinct. It seems that natural selection might be pretty good at helping us make it through today, but pretty awful at preparing us for tomorrow.

This is precisely what an experiment performed by Professor Michael Travisano in the Ecology, Evolution and Behavior Department and his colleagues in Japan now suggests: the soil bacterium Alcaligenes xyloxydans* - affectionately nicknamed Alcali - improved its way straight to extinction.

For a number of decades, lab-grown microbes like Alcali have been used to study evolutionary processes in real-time. Due to their minute size, huge population numbers, and quick reproductive rates, adaptations and their consequences can be studied in a matter of months. This is the strategy preferred by Dr. Travisano, who is mainly interested in the abilities and limits of evolutionary adaptations.

Alcali was placed in a stressful environment - liquid growth media where it was fed a noxious gloop - and its evolution was tracked. In this environment, we are very similar to Alcali: the trash we generate through our consumption and growth turns into toxic waste that eventually comes around to bite us in our flagellated buttocks – figuratively.

At the beginning of the experiment, Alcali grew slowly, but then showed an increased growth rate, reaching larger population numbers faster than before, suggesting that it adapted. Genetic variants that grew faster, produced more offspring than slower growers, eventually outcompeting them from the population.

A “live fast, die young” lifestyle pattern emerged in all of the experiment’s replicates. As it turns out, populations that grow faster in fact die faster, too.

Alcali population sizes were dangerously low, inching closer and closer to extinction. Fast growing Alcali were pretty good at outcompeting their neighbors for resources in the short-term, but were essentially bringing about their own extinction in the long-term.

Although we must be cautious when drawing parallels to other systems, the outcome of this experiment undermines the assumption that competition inherently produces the best outcomes.

We can imagine numerous examples in which competition in economic systems has led to improvements in efficiency and functionality, but we will do well to heed Alcali’s warning: individual competition for immediate short-term success does not always mean long-term success, and can lead directly to system collapse and extinction.

*also known as Achromobacter denitrificans A41

Travisano, M., Maeda, M., Fuji, F. et al. Rapid adaptation to near extinction in microbial experimental evolution. J Bioecon 20, 141–152 (2018).