Crabs have evolved five separate times – why do the same forms keep appearing in nature?

[Still Waters]

Charles Darwin believed evolution created “endless forms most beautiful”. It’s a nice sentiment but it doesn’t explain why evolution keeps making crabs.

Scientists have long wondered whether there are limits to what evolution can do or if Darwin had the right idea. The truth may lie somewhere between the two.

While there doesn’t seem to be a ceiling on the number of species that might evolve, there may be restraints on how many fundamental forms those species can evolve into. The evolution of crab-like creatures may be one of the best examples of this, since they have evolved not just once but at least five times.

But crabs aren’t the exception...

https://theconversation.com/crabs-have-evolved-five-separate-times-why-do-the-same-forms-keep-appearing-in-nature-195739