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Isn't it weird that we have exactly five fingers and five toes on each hand and foot.
(lemmy.dbzer0.com)
A "Showerthought" is a simple term used to describe the thoughts that pop into your head while you're doing everyday things like taking a shower, driving, or just daydreaming. The best ones are thoughts that many people can relate to and they find something funny or interesting in regular stuff.
The wikipedia article Polydactyly in stem-tetrapods has some explanations on how we ended up with 5 fingers and toes.
The gist of it is that tetrapods (four-limbed vertebrate animals) evolved from a fish similar to a lobe-finned fish that had 5 sets of bones in each of its fins that evolved into fingers and toes. Some tetrapods have subsequently lost digits but the basal state was five.
There's a book, Your Inner Fish by Neil Shubin that's full of this kind of stuff. Highly recommend.
I love it. So many things in the world don’t really have an “explanation,” they have a “story.”
The reason they are as they are is just because of prior conditions.
Amazing book. I recommend reading it if you're interested in evolution.