Header: Discharge from the gold mine, off the coast of Mindanao, Philippines, by Yann Arthus Bertrand.

30 Evolutionary Truths Everyone Should Know

As a little girl I was immensely fascinated by nature. I could stand on the terrance for hours watching birds, and for a long time in my childhood years, I did my own little “research” on snails and their spiral shells. Being curious of nature and why everything is the way it is, has always felt effortless and exciting to me. School did facilitate for this kind of inquiry in the first years of school, at least in my case. But what I’ve come to understand looking back, is the fact that the older I got, the more school, in the form of teachers, presented a kind of sealed case; “we know everything there is to know”. Fast forward to adulthood and this is clearly not the case, in fact quite the contrary.

It seems like biology and evolution are fields were we have vastly more to discover. Even though the things we know are significant, they are just a tiny fraction of the puzzle. For over 18 months I’ve been listening to a weekly podcast between two evolutionary biologists, where they discuss everything from animal behavior to romantic life to politics, through an evolutionary lens. It has brought back a spirit of inquiry for nature, why and how we are the way we are. The podcasters in questions also just released their new book – A Hunter Gatherer’s Guide to the 21st century. I just finished reading it, and it is absolutely fantastic. The book holds a myriad of insights to everyday life that will surprise, enlighten, and possibly improve your life.

In that spirit, I made this article with what I believe are 30 Evolutionary Truths Everyone Should Know. With complete list of notes and sources at the end.

30 Evolutionary Truths Everyone Should Know

1. Asking if a particular trait is due to nature or nurture implies a false dichotomy between nature, genes and evolution on the one side and between nurture and environment on the other. In fact, all of it is evolutionary.

2. Birds are the only clade of dinosaurs that did not go extinct sixty-five million years ago. So, yes, dinosaurs are not extinct.

3. We, humans, are mammals because we have descended, over tens of millions of generations, from the very first mammal, which roamed Earth nearly two hundred million years ago.

4. As early humans collaborated ever more with one another to gain control over their environment, their biggest competitors soon became each other. Humans cooperate to compete.

5. What mechanism explains lactase persistence in some human populations – European pastoralists, Scandinavians and Saharan people like the Bedouin? Among dairying people and their descendants, a genetic variant that provides a high capacity to digest lactose into adulthood is far more common than among populations that do not regularly consume dairy after weaning.

Dairy cows grazing between dunes, Maule province, Chile, by Yann Arthus Bertrand.

6. Individuals are not the same as populations.

7. Moving our bodies has positive effects on mental health.

8. Muting pain with medications interferes with the feedback system in our bodies, making it much harder for us to know what we should, or should not, do. Similarly, eradicating swelling in the wake of an injury means that you are much more likely to injure yourself again, in the same place.

9. Calluses are nature’s shoes, and they do a far better job of transmitting tactile information to your brain than do shoes. Be barefoot as often as possible.

10. Religiosity is adaptive. Religion is an efficient encapsulation of past wisdom, wrapped in an intuitive, instructive, and difficult to escape package.

11. In everything there are trade-offs. Pick any two traits, and they are in a trade-off relationship. Trade-offs exist whether they have been discovered or not.

12. Our ancestors may have been controlling fire for more than a million and a half years. The control of fire, and the subsequent invention of cooking, have been pivotal in making us into the humans that we are today.

13. Milk, fruit and nectar are the only foods produced by the organism with the expectation that their product would be eaten.

14. The consumption of fish, turtles, and other coastal foods may have been instrumental in the development of our large brains.

15. Sunlight calibrates your sleep-wake cycle far better than artificial light does. Spend time outside every day.

16. In mammals and birds, with our genetic sex determination, there is no sex change possible. No pigeon or parrot, no horse or human, has ever changed what sex they actually are. Behavior though, call it sex-role or gender, that is highly labile – open to change. Humans are the most labile, behaviorally, of all the animals.

17. Monogamy is the mating system with the greatest potential for cooperation and fairness, beginning with child-rearing. In primates, monogamy is also correlated with the largest relative brain size.

18. Sex and orgasm trigger the release of oxytocin in females, which promotes bonding. The situation is similar for males, except that it is not oxytocin but vasopressin that does the job.

19. Dogs are in many ways a human construct. Even before we began to farm, dogs were by many of our sides, becoming domesticated, and as hunter-gatherers, some humans already had dog friends.

20. Adults who were breastfed have better-formed palates and better-aligned teeth compared to those who were bottle-fed.

21. Humans are not blank slates, but of all organisms on Earth, we are the blankest.

22. Humans have the longest childhood on Earth, and we arrive in the world with more plasticity than any other species – meaning that we are the least set in stone.

23. Illnesses faced by mothers during pregnancy are often the result of a conflict of interest between mother and fetus – an often gentle but real tug-of-war for resources.

24. Humans are antifragile. We grow stronger with exposure to manageable risks, with the pushing of boundaries. As we grow into adults, exposure to discomfort and uncertainty – physical, emotional and intellectual – is necessary if we are to become our best selves.

Pirogue on the Niger river in the Gao region, Mali, by Yann Arthus Bertrand.

25. Let your children sleep. Sleep plays a crucial role in brain development, and when synapses – the connections between neurons – are being generated at a very high rate, sleep expands in scope as well.

26. While most fringe ideas are in fact wrong, it is exactly from the fringe that progress is made. This is where the paradigm shifts happen.

27. We need metaphor to understand complex systems.

28. Theory of mind provides potential access to a sense of fairness. The concept of what is “fair” didn’t originate from philosophers. It didn’t emerge with city-states, or with agriculture. It wasn’t new to hunter-gatherers, either, or to our first bipedal ancestor. Monkeys keep track of what’s fair, and what’s not, and they have decided opinions about unfair practices in their social realm.

29. Wherever perception is the mediator of success, you have deception as an important evolutionary force.

30. Diminishing returns occur in every complex adaptive system. A utopian vision, one that seeks to maximize any single parameter, falls prey to diminishing returns. So, learn to jump curves. Put another way: consider learning a new thing rather than being a perfectionist and trying to get ever better at whatever you already really, really good at.

Notes:

1. Heying, H. and Weinstein, B., 2021. A Hunter Gatherer’s Guide to the 21st century, 1:16, 42-44
2. Heying, H. and Weinstein, B., 2021. A Hunter Gatherer’s Guide to the 21st century, 2:26-29.
3. Springer, M. S., et al., 2003. Placental mammal diversification and the Cretaceous-Teritary boundary. Proceedings of the National Academy of Sciences, 100(3):1056-1061.
4. Alexander, R. D., 1990. How Did Humans Evolve? Reflections on the Uniquely Unique Species. Ann Arbor, MI: Museum of Zoology, University of Michigan. Special Publication No. 1.
5. Flatz, G., 1987. “Genetics of Lactose Digestion in Humans.”In Advances in Human Genetics. Boston: Springer, 1-77.
6. Heying, H. and Weinstein, B., 2021. A Hunter Gatherer’s Guide to the 21st century, Notes 1(15): 269.
7. Choi, K. W., et al., 2020. Physical activity offsets genetic risk for incident depression assessed via electronic health records in a biobank cohort study. Depression and Anxiety, 37 (2): 106-114.
8. Heying, H. and Weinstein, B., 2021. A Hunter Gatherer’s Guide to the 21st century, 4: 70.
9. Holowka, N. B., et al., 2019. Foot callus thickness does not trade-off protection for tactile sensitivity during walking. Nature, 571(7764): 261-264.
10. Chen, Y., and VanderWeele, T. J., 2018. Associations of religious upbringing with subsequent health and well-being from adolescence to young adulthood: An outcome-wide analysis. American Journal of Epidemiology, 187 (11):2355-2364.
11. Heying, H. and Weinstein, B., 2021. A Hunter Gatherer’s Guide to the 21st century, 3:48.
12. Bellomo, R. V., 1994. Methods of determining early hominid behavioral activities associated with the controlled use of fire at FxJj 20 Main, Koobi Fora, Kenya. Journal of Human Evolution, 27 (1-3): 173-195. Also Wrangham, Catching Fire.
13. Heying, H. and Weinstein, B., 2021. A Hunter Gatherer’s Guide to the 21st century, 5:82.
14. Braun, D. R., et al., 2010. Early hominin diet included diverse terrestrial and aquatic animals 1.95 Ma in East Turkana, Kenya. Proceedings of the National Academy of Sciences, 107(22): 10002-10007.
15. Wurtman, R. J., 1975. The effects of light on the human body. Scientific American, 233(1): 68-79.
16. Heying, H. and Weinstein, B., 2021. A Hunter Gatherer’s Guide to the 21st century, 7: 111.
17. Schillaci, M. A., 2006. Sexual selection an the evolution of brain size in primates. PLoS One, 1(1): e62.
18. Insel, T. R., et al., 1998. “Oxytocin, Vasopressin, and the Neuroendocrine Basis of Pair Bond Formation.” In Vasopressin and Oxytocin, Zingg, H. H., et al., eds. New York: Plenum Press, 215-224.
19. Bergstöm, A., et al., 2020. Origin and genetic legacy of prehistoric dogs. Science, 370(6516): 557-564.
20. Palmer, B., 1998. The influence of breastfeeding on the development of the oral cavity: A commentary. Journal of Human Lactation, 14(2): 93-98.
21. Heying, H. and Weinstein, B., 2021. A Hunter Gatherer’s Guide to the 21st century, Notes 9(4): 281.
22. Heying, H. and Weinstein, B., 2021. A Hunter Gatherer’s Guide to the 21st century, Notes 9(5): 146+281.
23. Haig, D., 1993. Genetic conflicts in human pregnancy. Quarterly Review of Biology, 68(4): 495-532.
24. Taleb, N. N., 2021. Antifragile: How to Live in a World We Don’t Understand, vol. 3. London: Allen Lane.
25. Frank. M. G., Issa, N. P., and Stryker, M. P., 2001. Sleep enhances plasticity in the developing visual cortex. Neuron, 30(1): 275-287.
26. Kuhn, T. S., 1962. The Structure of Scientific Revolutions. Chicago: University of Chicago Press.
27. Heying, H. and Weinstein, B., 2021. A Hunter Gatherer’s Guide to the 21st century, 10:183.
28. Brosnan, S. F., and de Waal, F. B., 2003. Monkeys reject unequal pay. Nature, 425(6955): 297-299.
29. Weinstein, B., September 2021. Youtube Interview https://www.youtube.com/watch?v=vm-4HS2khTw
30. Heying, H. and Weinstein, B., 2021. A Hunter Gatherer’s Guide to the 21st century, 11-13: 207+233.