(Roughly) Daily

Crab-like body plans have evolved independently at least five times. As Jason P. Dihn explains, biologists are still trying to figure out exactly why…

In 1989, paleontologist Stephen Jay Gould proposed a thought experiment: What would the world look like if we turned back time and replayed the evolutionary tape? “I doubt that anything like Homo sapiens would ever evolve again,” he concluded. Maybe not. But crabs might.

Evolution just can’t stop creating crabs. Believe it or not, the flat-and-wide body plan has evolved at least five different times. The process is called carcinization, and it’s inspired comics, memes and entire subreddits.

Still, biologists don’t know why crabs keep evolving. Figuring it out would satisfy the online masses, sure, but it would also be a step toward solving other important scientific mysteries. For instance, why some species share evolutionary paths while others forge unique ones (looking at you, platypus)…

Convergent evolution: “Evolution Only Thinks About One Thing, and It’s Crabs,” from @JasonPDinh in @DiscoverMag.

Will crabs need to (re-)evolve a sixth time? “Alaska’s snow crabs have disappeared. Where they went is a mystery.”

(Image above: source)

* Gregory Bateson

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As we fiddle with phylogeny, we might spare a thought for Walter Rothschild, 2nd Baron Rothschild; he died on this date in 1937. A British banker, politician and soldier, he is best remembered for his pursuit of his passion— zoology and his collection of species. At its largest, Rothschild’s collection included 300,000 bird skins, 200,000 birds’ eggs, 2,250,000 butterflies and 30,000 beetles, as well as thousands of specimens of mammals, reptiles, and fishes. They formed the largest zoological collection ever amassed by a private individual (and are now part of the Natural History Museum). He named dozens of animal taxa, published Novitates Zoologicae, and authored or co-authored scores of scientific papers.

Related: “How Bird Collecting Evolved Into Bird-Watching.”

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