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Comment: Re:Panspermia (Score 1) 85

by Torbjorn Larsson, OM (#42479875) Attached to: World's Oldest Fossils Found In Australia
Unlikely. See my longish comment above how ~ 30 000 years is now known to suffice until cellular ancestors arise. They only need 2 individually self-assembling and spontaneously replicating components, liposomes and the thermodynamically driven crystallising RNA replicators. For example, Mars with its mere ~ 3 million year until accretion got a head start on Earth with its ~ 30 - 300 million years (latest core formation theories) had an impactor tramway of material raining down on Earth as it formed. Calculate cellular mass content of average crust and its survivability under launch impact and shortest route to Earth (all researched and published, thankfully). Even if the martian tramway delivery rate was order of magnitude larger than today's ~ 200 kg/year estimate, you don't get the average delivery rate of 1 (one) surviving cell up to the above abiogenesis rate. I don't think we can reject the possibility at 3 sigma, but the simplest pathway of "in-house assembly" is the superior at 1-2 sigma. As for incoming life at later times, we don't see it in mass sequencing. Indeed, it would have a hard survive will already adapted life makes lunch out of it.

Comment: Re:Those are our oldest ancestors? (Score 1) 85

by Torbjorn Larsson, OM (#42479519) Attached to: World's Oldest Fossils Found In Australia
Bacteria has a lot of interesting sexual (or sexual like) traits, like sharing chromosomes by way of membrane tunnels. So something like it has evolved many times over. But evolution doesn't use "hopeful monsters" (macroscale mutations), but proceeds mostly along darwinian pathways: small, survivable, on average fitness increasing steps. (See near neutral genetic drift and genetic bottlenecks for variation driven pathways.)

When I left you, I was but the pupil. Now, I am the master. - Darth Vader

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