Tuesday, March 13, 2012

Two instances of altruism

at the most primitive stages of life.

“This question ‘why family?’ was only the beginning.  ‘Why family?’ led him to a bigger question: why does anybody help anybody?  If you think about Darwin’s idea (survival of the fittest) think about what that really means.  It means if you are a creature you have two big important jobs.”
“You gotta survive and you’ve gotta be fit.”
“Right.  Fitness means: how many babies can you make?  And so if you do some stupid, hair-brained thing [act of altruism], that means you can’t stay alive, or you can’t make babies…that doesn’t make any sense.”
“And yet, wherever you look in nature…”
“You see creatures doing this.”
“From bacteria.”
“Ants and wasps.”
“I’ll give you an example.  There’s a species of amoeba called  xxxx, which usually the amoeba usually lives on its own—it’s a single celled organism—in the forest.  But when resources are low, what it does is send out its chemical signal, and all the other amoeba…”
“They start sending out signals…”
“And they start crawling until they all meet, and they become one slug, which is now a single organism.”
“And this slug begins to crawl until it finds a place that’s windy and sunny, at which point…”
“It stops, and the top twenty percent of the slug—the top twenty percent of the amoeba, the slug—begin to create out of their own body, a stalk, which hardens, and they die while doing so.  But the stalk allows the bottom eighty percent to climb up the stalk and to create an orb at the top of the stalk…”
“And from there, all the amoeba that aren’t, you know, dead, can catch a wind…”
“To better pastures.”
“It’s like a dandelion.”
“So what’s happened is, that the top twenty percent have really sacrificed themselves for the back eighty percent: and that’s an amoeba…
—various voices on the Radiolab podcast.  Season 9.  Episode 1.  “The Good Show.”

“…the coccolithophores are not doing very well.”
“Well, they’ve got a couple of tricks up their little calcified sleeves.  Sometimes when a virus enters, the coccolithophores will send out a chemical signal…”
“They’re saying, ‘Hey, it’s too late for me…”
“but save yourselves…and initially this signal is pretty weak in the water but as more and more coccolithophores are infected the chorus of this chemical beacon grows louder and louder…”
“And so the other cells hear these messages…”
“And they change by messing with their DNA a little bit and they go from having those white shields on the outside to having these jaggedy scales…”
“Which we think might be impenetrable…”
“Well, why aren’t they scaly all the time?”
“Because when they’re scaly, they can’t be the best Coccolithophores they can be.  They just don’t grow as well.”
“So [being] scaly is an adaptation against the virus.”
“And then finally, if all else fails…”
“Program cell death.”
“The Coccolithophores just commit suicide.”
“It just shuts down and kills itself to prevent propagation of viruses.”
—various voices on the Radiolab podcast.  March 5, 2012.  “A War We Need.”  

Blog Archive