Background
In 2016 a Meta post discussed the problem of questions “that ask for why evolution did not lead to situation-X”. It was suggested that a community wiki question be created, and provided with an extensive range of answers. Then posters of such evolutionary questions could be referred to it and their questions closed as duplicates. This was done by @WYSIWYG, and attracted several good community answers, which, in my opinion, cover most of the bases. This is frequently used and is a valuable resource for the site.
Problem
One user (@terdon) suggested a title “If trait X would be advantageous to an organism, why hasn't it evolved?” but, in fact, the community question was given the broader title:
“Why do some bad traits evolve, and good ones don't?”
To my mind the main problem is that this is in fact two different questions which have quite different possible answers. This antagonizes many posters, especially as the less frequent concern (bad traits evolving) appears first in the title. Indeed it always annoyed me as, from the title alone, it seemed to me that the question was unlikely to be a duplicate. It was only this month when an answer came up on Meta that I actually looked at the community question and saw that it was different from my expectation and extremely useful.
A secondary problem I have is with that the wording of the title, which refers to “good traits”. In fact these are “traits that individuals believe would be advantageous” and I think the title should be rephrased to reflect this. Indeed one of the answers specifically deals with this urge for posters to play God with evolution, pointing out that their beliefs of what would be advantageous may well be incorrect.
Proposal
That I split the community question into two questions by editing the existing one and creating a second.
The edited question would be entitled:
Why has a trait that would appear to be advantageous not evolved?
- The new question would be entitled something like (suggestions for improvement solicited):
Why has a trait evolved that can have a deleterious effect on an organism or population?
Here one accepts that there are unequivocally deleterious effects, e.g. those resulting from haemoglobinopathies. Answers or part answers addressing this (fewer, but some good ones nevertheless) would be moved to the new question.
Anticipated objections to proposal
The main objection to this proposal that I anticipate is that there are a large number of instances of reference to the community question by its current title, and that it would be misleading if the links led to a question with a different title. I would volunteer to edit, but the references tend to be in close notices that are autogenerated and cannot be edited by normal users.
Why don’t I just go ahead and do it?
I could, but then someone might roll it back, and then I would want to argue the case and we would go to and fro… Better to discuss it first, so that people can consider before getting into a ping-pong game.
