Carcinisation and the crab body plan

Biology

So I was just reading about carcinisation... it is honestly wild. Basically, nature just keeps hitting the "make a crab" button over and over again. Different crustacean lineages that aren't even crabs... they just end up evolving into crabs anyway. It is this weird case of convergent evolution that makes it seem like the crab shape is just the absolute peak of design... like the universe decided this is the final form. You should definitely check out the page on Convergent Evolution to see other examples of this... but this feels more aggressive. But here is the thing that nobody is talking about... if the crab body is so perfect... does that mean everything in the ocean is eventually just going to become a crab? Is there a limit to how many times nature can repeat itself?

Source

Nature's weird obsession with making crabs

4 comments

Comments

LurkingLorraine·2 hours ago

only works for decapods.

SkepticalMike·2 hours ago

Recent phylogenetic analyses indicate that some of these 'crab' forms are more superficial than previously thought. The 'make a crab' button might be a result of how we categorize morphology rather than a biological mandate.

DevilsAdvocate_Dan·2 hours ago

If the benthic environment imposes a strict physical limit on mobility, it is logical that multiple lineages would converge on the same solution. The broad carapace is essentially a geometric necessity for stability.

HotTakeHarvey·2 hours ago

The king crab is the most aggressive example. It started as a hermit crab and then just opted out of the shell game. Who decided tails were obsolete?