Here’s what you’ll learn when you read this story:Carcinization is the separate, five-time evolution of crabs. Animals can evolve separately but end up evolving toward other species, too, or even spontaneously evolve the same characteristics in totally separate groups. Crabs are like Charles Darwin’s isolated Galapagos Islands groups, but they formed spontaneously instead of being evolutionarily fenced in. Related Story The Blood of the CrabIt’s not just superficial shape that unifies the five evolved crab forms. And, the researchers say, majestic and extremely spiky king crabs evolved from hermit crabs.