Natural Wonders from life's information (Evolution)

by David Turell @, Sunday, July 26, 2020, 00:45 (89 days ago) @ dhw

How do slime molds learn; how do 100 pieces of a flatworm make 100 new worms?

"Slime molds, for example, are very large single-celled organisms that can agglomerate into masses, creeping across the forest floor and feeding on decaying plants. (One type is called dog vomit slime mold, which gives you an idea of what they look like.) They can also retreat into a sort of freeze-dried capsule form, losing much of their protein and DNA in the process, and stay that way for months. But just add water and the reconstituted slime mold is good as new.

"They are also fussy eaters. If you put them down on top of their favorite meal of agar and Quaker oats and add salt or quinine to one part of it, they’ll avoid that part, at least at first. The biologists Aurele Bousard and Audrey Dussutour at the University of Toulouse and colleagues used this fact to show that slime molds can learn in a simple way called habituation. If the only way to get the oats is to eat the salt too, the molds eventually get used to it and stop objecting. Remarkably, this information somehow persists for up to a month, even through their period of dessicated hibernation.

"Flatworms are equally weird. Cut one into a hundred pieces and each piece will regenerate into a perfect new worm.


"Santosh Manicka and Michael Levin of Tufts University argue in the special issue that regeneration involves a kind of cognition. The process is remarkably robust: You can move the cells that usually make a head to the tail location, and they will somehow figure out how to make a tail instead. The researchers argue that this ability to take multiple paths to achieve the same goal requires a kind of intelligence.

"Regeneration involves the standard mechanisms that allow the DNA in a cell to manufacture proteins. But Dr. Levin and his colleagues have shown that flatworm cells also communicate information through electricity, signaling to other nearby cells in much the way that neurons do. In experiments that would make Dr. Frankenstein proud, the researchers altered those electrical signals to produce a worm that consistently regenerates with two heads, or even one that grows the head of another related species of flatworm.

"This research has some practical implications: It would be great if human accident victims could grow back their limbs as easily as flatworms do. But the studies also speak to a profound biological and philosophical conundrum. Where do cognition and intelligence come from? How could natural selection turn single-celled amoebas into homo sapiens? Dr. Levin thinks that the electrical communications that help flatworms regenerate might have evolved into the subtler mechanisms of brain communication. Those creepy slime molds and flatworms might help to explain how humans got smart."

Comment: We have covered this material before. The bold is a good question if you are an atheist, but simple if you believe the intelligence is God's and given to the living organisms in cellular genomes. Such intelligence doesn't arise out of thin air or by chance, and it certainly can't evolve from simple one-celled starting life, whose start is still totally unknown to us.

Complete thread:

 RSS Feed of thread

powered by my little forum