Sep 7, 2020 12:50 AM
(This post was last modified: Sep 7, 2020 03:09 AM by C C.)
https://www.theguardian.com/science/2020...lain-sight
EXCERPT: Planetary scientist Stuart Bartlett of the California Institute of Technology in Pasadena, working with astrobiologist Michael Wong of the University of Washington in Seattle, argues that we need to escape the straitjacket of Earth-based thinking about life. They propose introducing a broader category called “lyfe” (pronounced, in an oddly West Country fashion, as “loif”), of which life as we know it is just one variation. “Our proposal attempts to break free of some of the potential prejudices due to us being part of this one instantiation of lyfe,” says Bartlett.
They suggest four criteria for lyfe:
1. It draws on energy sources in its environment that keep it from becoming uniform and unchanging.
2. It grows exponentially (for example by replication).
3. It can regulate itself to stay stable in a changing environment.
4. It learns and remembers information about that environment. Darwinian evolution is an example of such learning over very long timescales: genes preserve useful adaptations to particular circumstances.
The two researchers say there are “sublyfe” systems that only meet some of these criteria, and also perhaps “superlyfe” that meets additional ones: lyfe forms that have capabilities beyond ours and that might look on us as we do on complex but non-living processes such as crystal growth.
“Our hope is that this definition frees our imaginations enough to not miss lyfe that might be hiding in plain sight,” says Bartlett. He and Wong suggest that some lyving organisms might use energy sources untapped here on Earth, such as magnetic fields or kinetic energy, the energy of motion. “There is no known life form that directly harnesses kinetic energy into its metabolism,” says Bartlett.
They say there might be other ways of storing information than in genetic strands like DNA. Scientists have, for example, already devised artificial ways to store and process information using two-dimensional arrays of synthetic molecules, like checkerboard arrays or abacuses. Bartlett says that the distinction between lyfe and non-lyfe might be hazy: being “alyve” might be a matter of degree. After all, scientists already argue about whether viruses qualify – although no one doubts their ability to wreak havoc with life.
He’s sceptical of the notion in Nasa’s working definition that lyfe/life can only arise and develop by Darwinian evolution. He says that even terrestrial organisms can shape their behaviour in ways that don’t depend on Darwin’s mechanism of random mutations coupled to competition for resources that selects advantageous mutations. “While Darwinian evolution does of course occur, I think it needs to be augmented into a larger picture of biological learning,” he says... (MORE - details)
EXCERPT: Planetary scientist Stuart Bartlett of the California Institute of Technology in Pasadena, working with astrobiologist Michael Wong of the University of Washington in Seattle, argues that we need to escape the straitjacket of Earth-based thinking about life. They propose introducing a broader category called “lyfe” (pronounced, in an oddly West Country fashion, as “loif”), of which life as we know it is just one variation. “Our proposal attempts to break free of some of the potential prejudices due to us being part of this one instantiation of lyfe,” says Bartlett.
They suggest four criteria for lyfe:
1. It draws on energy sources in its environment that keep it from becoming uniform and unchanging.
2. It grows exponentially (for example by replication).
3. It can regulate itself to stay stable in a changing environment.
4. It learns and remembers information about that environment. Darwinian evolution is an example of such learning over very long timescales: genes preserve useful adaptations to particular circumstances.
The two researchers say there are “sublyfe” systems that only meet some of these criteria, and also perhaps “superlyfe” that meets additional ones: lyfe forms that have capabilities beyond ours and that might look on us as we do on complex but non-living processes such as crystal growth.
“Our hope is that this definition frees our imaginations enough to not miss lyfe that might be hiding in plain sight,” says Bartlett. He and Wong suggest that some lyving organisms might use energy sources untapped here on Earth, such as magnetic fields or kinetic energy, the energy of motion. “There is no known life form that directly harnesses kinetic energy into its metabolism,” says Bartlett.
They say there might be other ways of storing information than in genetic strands like DNA. Scientists have, for example, already devised artificial ways to store and process information using two-dimensional arrays of synthetic molecules, like checkerboard arrays or abacuses. Bartlett says that the distinction between lyfe and non-lyfe might be hazy: being “alyve” might be a matter of degree. After all, scientists already argue about whether viruses qualify – although no one doubts their ability to wreak havoc with life.
He’s sceptical of the notion in Nasa’s working definition that lyfe/life can only arise and develop by Darwinian evolution. He says that even terrestrial organisms can shape their behaviour in ways that don’t depend on Darwin’s mechanism of random mutations coupled to competition for resources that selects advantageous mutations. “While Darwinian evolution does of course occur, I think it needs to be augmented into a larger picture of biological learning,” he says... (MORE - details)
