Chasing Evolution is Fighting Darwin

A groundbreaking study of ants several years ago found that many ants in a colony are inactive.[1] [2] The ant colony in question had a 40 percent “unemployment rate”.

This is amazingly inefficient, but the researchers noted it makes the colony more resilient. The unemployed ants provide adaptive capacity – they improve the colony’s odds of surviving setbacks. ?If worker ants go missing due to predators or ant wars erupt with other colonies, inactive ants can substitute for them. Nor do human societies aspire to efficient, full employment: a low but non-zero target unemployment rate is considered desirable, to reduce inflationary pressures.

Ants are spectacularly successful – being 15 to 20 percent of the mass of all land animals on the planet[3] – and other social insect species have been reported to have 50 percent or more inactive workers at a given time.[4]

Whatever the real-life range we can still infer that over the past 140 million or more years of ant evolution, inefficient-but-resilient ant colonies outcompeted “efficient” ant colonies in which all ants were active. If efficiency-optimizing ant colonies were ecologically competitive in any environment, we should have observed them by now. Conversely the biggest danger to ant colonies would come from McKinsey consultants recommending half their workers be terminated…!

The Boreal Forest

Broadleaf trees such as maple, oak and birch have large leaves and wide crowns (canopies). This makes them well-suited to maximize photosynthesis; they allow the tree to make the greatest use of the available sunlight.

Canada’s boreal forest is however dominated by conifers which are covered with thin needles and grow in the shapes of narrow cones: exactly the “wrong” features for maximizing photosynthesis.

Conifers dominate Canada’s boreal forest because they’re more resilient to the environmental conditions they face. Conifers’ needles have waxy coatings which reduce moisture loss – a greater concern in the north than in temperate or tropical regions – and their narrow, often downward-facing branches are more likely to shed snow than break under an accumulation of weight, as upward-growing broadleaf branches are prone to do.

Being more efficient in best case scenarios isn’t as important as surviving (being resilient to) the much worse scenarios that always arrive. That’s why Herbert Spencer summarized Darwin as “survival of the fittest” and not “survival of the most efficient”.[5] Setbacks are inevitable and it’s resilience – not efficiency – that mitigates their impact. Without a resilient enough foundation, chasing efficiency amounts to fighting Darwin.

Which brings us to…

Photosynthesis

Photosynthesis is the direct or indirect basis for most life on earth. It’s the process by which plants transform sunlight (along with water and carbon dioxide) into the sugars that themselves become their body structure. It also produces oxygen as a byproduct.

The highest intensity of sunlight occurs roughly in the green region (500-570 nm). Based on efficiency we’d expect photosynthesis to have evolved to absorb the plentiful light from these frequencies. It did not, as shown below.[6]

?

Photosynthesis is dominated by chlorophylls which absorb less-intense blue light (430-470 nm) and red light (650-680 nm), and little else.[7] That’s why its efficiency is commonly estimated to be 1 to 2 percent: it ignores most of the light spectrum.[8]

This configuration provides stability (resilience) at the expense of efficiency, as seen from the excerpts of two recent scientific papers below (emphasis mine):

“… These facts suggest terrestrial green plants are fine-tuned to reduce excess energy absorption by photosynthetic pigments rather than to absorb [photosynthetically active radiation] photons efficiently.” [9]

“[the network model] explains how using pigments with [a chlorophyll-like] absorption-peak pattern can mitigate internal and external fluctuations in energy transfer, minimizing noise in output power … The model accurately reproduces absorption peaks for three diverse photosynthetic systems from different spectral environments. Such a mechanism may provide an underlying robustness to biological photosynthetic processes that can be further tuned and tweaked to adapt to longer-scale fluctuations in light intensity.” [10] [11]

?

After about 3 billion years – that’s 3,000,000,000 – of evolutionary competition, the form of photosynthesis that dominates the world is one that ignores a huge swath of the most intense wavelengths of light and is not actually optimized to efficiently absorb photons. Photosynthesis seems to have instead evolved in the direction of resilience: mitigating input fluctuations, minimizing output fluctuations, and even reducing excess energy absorption.

Reducing input fluctuations, minimizing output fluctuations, and turning back excess incoming resources even when they’re available closely parallels the Toyota Production System (broadly called Lean Production) to which we will soon turn.

Next time, though, we’ll consider how resilience in nature may inform our thinking when it comes to the energy systems we rely on.

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[1] A summary for general audiences can be found here: University of Arizona 2017, “Lazy ants make themselves useful in unexpected ways”, Phys.org, 08 September 2017, Accessed 08 August 2024, https://phys.org/news/2017-09-lazy-ants-unexpected-ways.html

[2] Charbonneau D, Sasaki T, Dornhaus A (2017) Who needs ‘lazy’ workers? Inactive workers act as a ‘reserve’ labor force replacing active workers, but inactive workers are not replaced when they are removed. PLoS ONE 12(9): e0184074. https://doi.org/10.1371/journal.pone.0184074. Accessed at: https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0184074.

[3] T.R. Schultz, In search of ant ancestors, Proc. Natl. Acad. Sci. U.S.A. 97 (26) 14028-14029, https://doi.org/10.1073/pnas.011513798 (2000).

[4] See prior footnote.

[5] A modern example is how the automobile dominates transportation in North America despite cycling being an order of magnitude more efficient in terms of energy consumption per km of travel. This is despite the amazing cost and inefficiency of moving 50 kg humans in 1000 kg metal shells - as if we’d directly descended from hermit crabs!

[6] Data for sunlight wavelengths obtained from ASTM G-173 standard, accessed via US National Renewable Energy Laboratory at: https://www.nrel.gov/grid/solar-resource/spectra-am1.5.html.

Chlorophyll absorption spectra obtained from Appendix A of: Clementson LA, Wojtasiewicz B. Dataset on the absorption characteristics of extracted phytoplankton pigments. Data Brief. 2019 Mar 29; 24:103875. DOI: 10.1016/j.dib.2019.103875. Accessed from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6461595/

[7] The reason plants appear green is because chlorophylls reflect green light instead of absorbing it.

[8] Gates, David M., Thompson, Michael B., Thompson, John N. "biosphere".?Encyclopedia Britannica, 17 Mar 2025, https://www.britannica.com/science/biosphere. Accessed 17 March 2025.

[9] Kume, Atushi; Importance of the green color, absorption gradient, and spectral absorption of chloroplasts for the radiative energy balance of leaves, J Plant Res. 2017; 130(3): 501–514. DOI: 10.1007/s10265-017-0910-z. Accessed 06 August 2024 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5897488. A correction was subsequently issued to update the paper’s copyright to Creative Commons. See: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5916983/

[10]? Arp TB, Kistner-Morris J, Aji V, Cogdell RJ, van Grondelle R, Gabor NM. Quieting a noisy antenna reproduces photosynthetic light-harvesting spectra. Science. 2020 Jun 26;368(6498):1490-1495. doi: 10.1126/science.aba6630. PMID: 32587021. Accessed at: https://www.science.org/doi/epdf/10.1126/science.aba6630

[11] In biology and other fields, robustness describes systems which can absorb and withstand shocks, without needing a recovery period to recover from them. It is a subset of what would would colloquially be called resilience.