Re: Last universal but not universal common ancestor of life

On 6/9/25 5:29 AM, jillery wrote:

You state above a common misunderstanding.

It's not a misunderstanding at all.
I have "commonly" complained about language use. Language is
a means to communicate ideas, concepts -- information. In
science, it's supposed to be exact. And yet we frequently
see idiotic language use, as in this case.
Another example, one going back quite a few years, is my
complaint about referring to humans as apes. Because this
implies a relationship which is just not true. The Chimp,
for example, descends from an upright walking ancestor with
a hand more like our own than that of a modern Chimp.
Bipedalism is older than the Chimp/Homo split.
Yet, the language use has fostered the idiotic notion of
a Chimp like LCA swinging from vines...
"Universal" is a false statement. We are NOT speaking of
a "Universal" ancestor to all life. There may he such an
ancestor, such an origins, but if there is we don't know
that yet. We have no clue. We can't even rule out
multiple points of origin for modern life on earth.

   Life on Earth
could have started many times and many places, and likely did.

It's more complicated than that. Life may not only have
arisen in parallel, it may have converged! "Symbiosis."
There were many, many cases where a symbiotic relationship
appears to have resulted in two or more organisms fusing
into one. If any of those organisms, pre fusion, arose from
a unique abiogenetic event, there is no single point of
origin for the organism resulting from the fusion.
     ...no single common ancestor.

However, the evidence suggests that lineages from only one time and
place survived to populate the Earth.

There's no such evidence. We'd first have to "Prove" that
abiogenesis is even possible. Then we'd need to rule out
multiple paths, or that different paths produce such different
life as to rule any type of fusion. And, we'd also need to
rule out any of those different life forms surviving even
today...
As is, we're stuck in this PARADOX where any life that
evolves anywhere must have DNA/RNA but at the same time
that DNA/RNA has to be sufficiently different for that
independent origins to be immediately recognizable, and
incompatible with all other life forms.
"They have to be the same, and different!"

This is the same reasoning for mitochondrial Eve and Y-chromosome
Adam.

So the Google on the origins of mtDNA, to see where I'm
coming from.
"Life is complicated.. LET'S GO SHOPPING!"
--
https://jtem.tumblr.com/tagged/The%20Book%20of%20JTEM/page/5