Basically, all those arms are heads.īARBER: Yeah. SHAPIRO: What does that even mean? What about the five starfish arms? What? So here's Christopher Lowe, an evolutionary biologist who was a co-author of the paper.ĬHRISTOPHER LOWE: There are, in fact, a giant head, and they've lost their trunk rather than having lost their heads. Am I right?īARBER: Funny enough, it's neither of those.īARBER: Yeah. SHAPIRO: I have to confess, I saw a headline about this. Ari, do you have a guess? Are starfish all tails or all limbs? SCOTT: Right? So, yeah, this new paper out this week in the journal nature settles this debate once and for all. SHAPIRO: There's definitely a metaphor here, but I'm not going to guess what it is. One idea was they became all tails.īARBER: The other one argues that starfish were basically all limbs, with no real head or tail, just a mouth and an anus. They both involve the starfish losing their heads through evolution.īARBER: Yeah. SCOTT: And recently there have been these two leading hypotheses. And then they transform into adults with five identical limbs. So scientists have wondered, what's up with the body structure of starfish? As larvae, they start out with two distinct sides, like a lot of animals, actually. A 200-year-old mystery about starfish anatomy.īARBER: Yeah, Ari. And, Regina, you have got something to cheer us up after that bad news about sea ice. Let's stick with stories about the water. The exposed ocean water that doesn't freeze absorbs more heat than ice does, and that makes it more difficult for ice to reform the next year. And when we have a bad year like this one, it's difficult for sea ice to recover. SHAPIRO: And that does lead to sea level rise.īARBER: Exactly. So without that protective shield of sea ice, those glaciers and ice shelves on land can melt faster. SCOTT: But Antarctica's sea ice does lead indirectly to sea level rise because it protects the continent's glaciers and the massive ice shelves from storms and ocean water that can eat away at their ice. The level of water in your glass is still about the same. It's kind of like an ice cube melting in your glass of water. Like, disappearing sea ice doesn't actually add extra water to the ocean. What does that mean for Antarctica and the rest of the world?īARBER: Well, one big thing is that it can contribute to global sea level rise, but not the way you might think. So this new analysis found that this year, there was substantially less ice than ever before, going back to when satellites started tracking this around 1980. Sadly, the amount of sea ice has been shrinking, partly because of warmer ocean water from climate change. And usually at that point, there's so much sea ice that it doubles the size of the continent. And in September, the sea ice is at its most expansive for the year. Deep winter in Antarctica is in July, August and September. SHAPIRO: Each Antarctic winter, which would be summer here in North America, where we are.īARBER: Right. Today we're going to focus specifically on research about Antarctica's sea ice.īARBER: And when we say sea ice, we mean the seawater around the continent that freezes and floats on the ocean's surface. Our NPR colleague Rebecca Hersher just reported on new science about melting ice across Antarctica. So, Ari, this is, of course, not great news. Let's get the bad news out of the way first. SCOTT: And staying up all night can ease depression - in mice.īARBER: And a record low for Antarctica's sea ice. What have you got for us?īARBER: How about the weird anatomy of starfish? SHAPIRO: You have, as usual, brought us three science stories that grabbed your attention this week. Aaron Scott and Regina Barber, welcome back. Time now for our science news roundup from our friends at NPR's Short Wave podcast.
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