I’ve taught evolution repeatedly. I talk about natural selection and how it doesn’t select for the best, it selects the best of what’s available. This isn’t a foreign concept to people. We do this consciously all the time. And yet, most of us still have trouble commiting to this piece of information.
When we are standing in the produce section of the grocery store we aren’t picking the best of all possible carrots, we’re looking for the best carrots out of the ones that are available. And our criteria for what is best varies depending on what we need at the time. A person who lacks food security is probably going to choose non-organic or the newer lines of “imperfect” food items that don’t meet our arbitrary aesthetic standards and are finally being shipped to market and sold for lower prices rather than tossed. An individual who wants to contribute to reducing food waste will likely choose the same items. Meanwhile, someone else might prioritize the biggest, or the ripest, or the most organic. But ultimately, regardless of what criteria is being used, we can each only choose from what is available.
While the element of active choice is absent from natural selection the idea that the selection can only be made out of the available options does hold. Natural selection does not select the organism that is the best possible for a particular setting or need, it selects the best of what is available.
Consider for a moment a peacock’s tail. While this is an example of sexual selection – females select males with bigger brighter tails because if he can survive with something so ridiculous holding him back he must be pretty fit. This is a pretty insane thing because the very thing that makes the male popular also makes it more difficult for him to survive.
Humans have many examples of these best of the available but not particularly great adaptations with our pelvis often cited as one of the most glaring examples because it leads to a number of issues including back and knee problems.
I know all of this. I teach all of this. And yet I still get caught. My surgeon for my wrist keeps talking about doing ulnar nerve relocation surgery. Basically he would move my nerve so that it takes a different path through my elbow in an attempt to get rid of the numbness in my arm. Aside from the fact that I just don’t want another surgery, I realized the other day that part of my hesitation stems from the thought that moving the nerve would mean moving it from where it is “supposed” to be. Yes, evolution and natural selection have resulted in my nerve in one particular location but that doesn’t mean that is the best place for it, just that that is where it ended up because it was the best of what was available.
I am pretty well read and well researched and yet I fell into a trap of how I was thinking about something not because I didn’t know better, but because I had never had a reason to put these two thoughts together. This is an important point for how we communicate science. Often the people we think are making insane choices based on very clear science haven’t put things together and it doesn’t mean they aren’t intelligent and capable, it just means that they haven’t put those things together in that way. In many ways they are doing the same as natural selection, they are going with the best option that is available to them and that often doesn’t include the best option.