On Friday, September 17, 2021 at 4:12:34 PM UTC-4, Glenn wrote:
> On Friday, September 17, 2021 at 12:03:06 PM UTC-7, Peter Nyikos wrote:
> > On Thursday, September 16, 2021 at 8:05:32 PM UTC-4, erik simpson wrote:
> > > Even further back:
> > Than what? The last part of the title could be misleading, because the
> > original unicellular-to- multicellular transition was "even further back"
> > than the unicellular-to- multicellular transition that the authors talk about.
> Such thoughts immediately came to my mind, after reading the OP. So I should assume that others have as well, and some more extensively,
> and with more knowledge of the current claims of science than I. But I wasn't surprised to find the up front claim "How animals evolved from a single-celled ancestor..."
Which is true in a sense, but with the screwy definitions that cladistic classification
has produced, the default assumption is "last single-celled ancestor of all living animals".
The movers and shakers of present day systematics are no more respectful of
fossils than the average creationist.
And so, that elusive entity might have been the last common ancestor of animals and
fungi, or even further back, with all living animals evolving from a multicellular
entity that may have already been well on the way to solving the
"cell adhesion, cell–cell communication and gene regulation"
problems that the abstract talks about.
Note, however, that many different groups of fungi have also solved these problems.
So the big question is whether that elusive "last single-celled ancestor of all living animals"
was a lot further back than the first (multicellular, by this scenario) fungus, or
whether fungi solved all these problems independently of animals. My vote goes
for this second alternative.
> In a brief exchange with Ron a month or so ago, he claimed that first life would not have been encapsulated (for lack of a better or more technical term) by a membrane, but free "swimming" so to speak.
Ron O is an immovable dogmatist on many things, so it wouldn't surprise me if he
was as unequivocal as you make him sound. But it's stupid to say that the first
efficient replicator had no outer membrane, because then every chunk of RNA,
or whatever, that preceded it was at the mercy of a bewildering variety of other
organic compounds that it would have been shielded from by a properly
permeable [not too little and not too much] membrane.
> And he could be right.
I'm not ruling it out. His scenario also has advantages. This is one debate that
OOL theorists have had for over half a century, perhaps over a century in various forms.
> Of course, if I claimed that first life would have been multicellular in the same sense of lacking individual membranes in "cells", I'd be labelled a kook.
Yeah, you aren't Ron O, who is much more popular than you [just ask Hemidactylus], and
who could probably get away with it.
Since you are Glenn, your theory would be lampooned as a throwback to 19th century
hypotheses about something (I forget the name, but it would have been one big mass of
"protoplasm") covering the bottoms of the oceans.
You'd have to distance yourself from that sneer by hypothesizing big chunks,
no bigger than the biggest living thing today
[some titanic fungus millions of years old, in Oregon IIRC]
with various centers of active genomic reproduction to whatever degree of fidelity
was possible.
>I think it is a fact that we don't have a clue as to what first life was or what happened early in the "tree" of life, which as I understand is turning into something of a bramble bush.
"mycelium" is the term I use. Strands merging and splitting in an intricate web,
until lateral transfer has "cooled" to where a number of trunks emerge from the
ground, each a portion of the tree of life. And perhaps all but one of the trunks
died out to produce the Tree of Life that is "visible" today.
Or perhaps two: eubacteria and archae. The dominant theory now is that
eukaryotes came about when (1) an archaebacterium went into symbiosis with
one or more kinds of (2) eubacteria. (1) went on to become the nucleus as
more and more of the (2) surrendered their genetic material to it.
In fact, the "supradominant" theory is that we "know" what kind of eubacterium (2) was.
I forget the name, but I could easily look it up, and so can you, because Minnich
was mercilessly raked over the coals a month or so ago in talk.origins for daring to question
the precise identification that this "supradominant" (2) at Dover, 2005.
As far as the Overdogs of talk.origins are concerned, it is all settled science, just like
"Birds are dinosaurs. The debate is over."
> And I suspect that we will never, until and if OOL research actually produces something besides rhetoric.
Agreed.
Peter Nyikos
Professor, Dept. of Mathematics -- standard disclaimer--
Univ. of South Carolina at Columbia
http://people.math.sc.edu/nyikos
PS I've left in the rest below, because it segues reasonably well with what I wrote above.