this post was submitted on 02 Nov 2024
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Horseshoe crabs. Unchanged for hundreds of millions of years.
Or just the form of a crab in general! Carcinisation is so weird, but apparently evolution sometimes goes "Let's just do crab again, that shit was ๐".
I genuinely fail to see why it's a thing. Like reading up it, it's basically just convergent evolution of crustaceans to a crab-like shape.
Couldn't the same be said for a ton of fish-like animals? The many attempts of nature to develop a fish? Hell, even some mammals went back to the fish, plan, although with the tail-fin the wrong way and having to visit the surface to breathe.
Or large-ish mammals all having pretty much a similar bodyplan, four limbs, head and neck.
Like surely there's something so specific in carcinisation that I just haven't picked up on yet. If someone know what it is pls inform me.
I'm not an expert, but my understanding is that the science indicates all mammals have a common ancestor. Not certain about fish, but I think that's a similar case?
To me, the surprising part about carcinisation is that, the form of a crab seems oddly specific, but non-obvious. I mean, I look at the form of a fish and think, "yeah, it makes sense why that shape would be favored in water," but I look at a crab and think "guess that's just what worked out for your ancestors. Tough luck, buddy." But apparently it's not just bad luck, it's a common strategy.
Did you know humans are more closely related to catfish than catfish are to dogfish?
QI | No such thing as a fish
Yeah, I can see that. But also it's swimming in water. Then again if tou want to crawl around the bottom? Hexapod is probably the way to go. But then you also need to be able ro manipulate shit, so frontlimbs become bigger.
Like a lot of space vehicles meant for surface exploring, both imagined and real, are usually six-wheeled, probably for added stability in a rocky terrain where there's a bit less gravity and sometimes storms and whanot. And what is it like on the ocean floor? Rocky, basically "less gravity" and odd flows like storms.
Idk there's a bit more to it I guess, I'm just looking for what that bit is, or if there indeed is one.
Yeah, that QI clip came to mind when you mentioned it, but to your point the shape that we consider "fish-like" shows up a lot in water. Even whales and dolphins figured out a similar shape, despite them not being fish (though they might still be etymologically related if you go back far enough?)
Ok, I can buy that the shape of a crab is probably optimized for a certain lifestyle.