Roly Polies Came From the Sea to Conquer the Earth | Deep Look

Pill bugs…… roly polies….. potato bugs… whatever you want to call them, somehow there’s something less creepy about these guys than other insects. More loveable, or something. Maybe it’s because they’re not insects
at all. Pill bugs are actually crustaceans. They’re more closely related to shrimp and
lobsters than crickets or beetles. Pill bugs even taste like shellfish, if you
cook them right. Some adventurous foragers call them wood shrimp. As early as 300 million years ago, some intrepid
ancestor crawled out of the ocean, sensing there might be more to eat, or less competition,
on dry land.” But unlike lobsters, pillbugs can roll up
into a perfect little ball for protection. If you look closely you can see the evidence
of where these guys came from. Like their ocean-dwelling cousins, pill bugs
still use gills to breathe. True insects — like this cricket — use a
totally different system. See those tiny holes on this cricket’s abdomen? They’re called spiracles. They lead to a series of tubes that bring
fresh air directly to the insect’s cells. But pill bugs don’t have any of that. To survive on land, they had to adapt. Their gills, called pleopods, are modified
to work in air. Folds in the pleopod gills developed into
hollow branched structures, almost like tiny lungs. In a way, the pillbug is only halfway to becoming
a true land animal. Because… they’re still gills. They need to be kept moist in order to work. Which is why you usually find pill bugs in
moist places, like under damp, rotting logs. They can’t venture too far away. Sure, pill bugs look like the most ordinary
of bugs. But they’re much more than that: evidence
that over evolutionary time, species make big, life-changing leaps. And those stories are written on their bodies. Hey, while we’re on the subject of oddball
crustaceans… check out this episode about mantis shrimp. Their eyes see colors we can’t even
comprehend. Their punch is faster than Muhammad Ali’s. And while we have you: Subscribe. OK? Thank you! And see you next time.


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