alt Hacker News>That just leaves one mystery: why wombats evolved cubic poop in the first place. Hu speculates that because the animals climb up on rocks and logs to mark their territory, the flat-sided feces aren't as likely to roll off from these high perches.
Whenever I read such snippets from biology, I wonder how natural selection pressure can lead to such specific outcomes. Wombats that mark their territory better over centuries or millennia are more likely to survive? Marking territory is more a form of communication than anything else, but its effect are subtly strong enough over time to lead to a discernible selection pressure for square-pooping wombats over others?
I often wonder how more biologists aren't believers (though I'm not necessarily one myself), when they encounter such intricate design in biology every single day
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Yes, it seems the "why" here is more interesting than the "how", and is indeed going to be a matter of speculation.
As far as evolution in general, the big picture is more about "punctuated equilibrium" than incremental change. Individual genetic changes from parents to child are typically just benign and so accumulate in any inter-breeding population without much effect. Once in a while the environment may shift in some fairly major way (easier for environment to change quickly than genetics) and then an accumulation of previously benign changes may suddenly become collectively impactful in a positive or negative way.
I don't see any reason to assume that square poop was ever selected for - maybe it's just a harmless consequence of some genetic change that was impactful in another way. Speculating that square Wombat poop evolved to not fall off rocks is a "just so story" that raises more questions than it answers.
> I often wonder how more biologists aren't believers
Many observations are unexplained, and not just in biology. The difference between believers and atheists is that atheists stop there: it is unexplained, at least for now, that's how things are. Believers will instead attribute it to god, or some other form of higher power. In the end, it just shifts the problem, at some point you will have to admit that some things just are and there is no explanation, for atheists, these are the things themselves, for believers, it is god who made the things.
That's why being a believer or being an atheist doesn't have much to do with being a biologist. It is just a philosophical view of how you deal with the unknown and the unknowable. The only thing is that the religious dogma should not get in the way of proper science. That life is so beautiful that god must be behind it (are we still talking about poop cubes?) shouldn't prevent biologists from searching for an evolutionary explanation.
Also, evolution is mostly random, not everything needs natural selection, sometimes, things happen for no good reason. Maybe a particularly prolific male in a particularly successful colony happened to have a square poop mutation or something.