After the Earth cooled down from the formation process it appears that life formed quite rapidly. Just because we humans don't understand all the complex interactions regarding abiogenesis doesn't mean that nature is not poised to create life when the opportunity presents.
it's known what must happen for abiogenesis to happen.
a group of molecules must come together to form an actual molecular machine.
there's a nobel waiting for the person that figures it out.
not only that, but the information contained within the cell must have a realistic explanation.
As has been explained to you ad nauseam soft bodies are not good candidates for fossilization.
yes, except koonin states they were fully formed, bones and all.
no trace of these bones has been found.
also, keep in mind that koonin specifically states they arrived here by a star (radially) pattern, NOT by a bifurcating tree like pattern.
the reviewers of his paper do not question him on this.
Koonin's forest of life does not depict organisms but FUEs (Fundamental Units of Evolution). The simplified version of what an FUE is is a gene or set of genes.
i'm not sure what the particular manuscript was, i guess i'm back to scanning my sources.
HGT is more likely to impact microorganisms like bacteria for various reasons. Off the top of my head two reasons that come to mind are 1) some bacteria have specialized structures (pilus) solely for the purpose of facilitating HGT which eukrayotes simply do not have, and 2) in multicellular organisms in order to pass on an HGT event it must occur in the gametes or cells that will eventually become gametes, and that is a small percentage of all the cells such an organism will have. Due to the high levels of HGT in microorganisms and its relatively high impact on those organisms, the tree of life analogy begins to break down at its' core, and instead something like a web of life is a more apt description.
glansdorf seems to disagree.
he apparently thinks HGT isn't as rampant as some believes it is.
this seems to support transposons quite well, especially since both exhibit the same behavior.
What Koonin has proposed is that we shift talk of evolution away from organisms and instead focus FUEs, or genes to simplify the concept. The basic idea being that given the prevalence of HGT in microorganisms the evolutionary history of specific species becomes dwarfed by the evolutionary history of FUEs which are not contained to a given species and can jump around. As with any generalized formulation of a scientific phenomena Koonin explains the special case of the tree pattern among multicellular eukaryotes with the idea of 'ensembles of FUEs' or groups of FUEs that are tied together in a single multicellular organism. Koonin calls this idea the "forest of life" as contrasted by the "tree of life". I think Koonin's work here is important as biologists try to figure out how to incorporate new understandings of biology into the theory of evolution, but I would not take Koonin's work dogmatically.
i don't think you can take ANYTHING concerning evolution dogmatically.
I gave a hint in my first post; the ages of 3.7 and 3.4 billion years suggests to me (assuming each are the result of life) that they would have come from the same abiogenesis event.
As I said at the top of this post the current thought is that life emerged relatively quickly after the Earth cooled from its' formation process which was roughly 4.5 billion years ago. However, the Earth was bombarded with asteroids - debris left over from the formation of the solar system, and some were quite large, as in large enough if hit to sterilize the planet. This has caused many scientists to theorize that life emerged on Earth several times in this early period where each time life started Earth was hit by an asteroid or series of asteroids whose energy sterilized the planet. It is during this time period that the moon was formed when a giant proto-planet sized object smashed into Earth. The theorized estimates of the number of times life got started before being wiped out range from single digits to 50 or so, and IIRC there are some extreme proposals that go up to 100+. These asteroid impacts were reduced greatly by around 4.0 billion years ago as the debris were more and more cleared out by the planets. So two observed life in the rocks dating to 3.7 and 3.4 billion respectively would indicate that the older life would not have been wiped out by asteroid impacts and is likely to be evolutionarily related to the younger life.
koonin discounts the mainstream explanation for the cambrian as unreliable.
he includes a reference for why he says this.
the reviewers do not question him on this either.
Of course the caveat to this conclusion is that all extant life is derived from a common ancestor (or common community of ancestors a la HGT). No one really knows, but things like how all cellular life uses DNA is seen as a strong indicator that all extant life is derived from a common ancestor.
yes, koonin does state the evidence is overwhelming, and like you i assume a large part of this overwhelming evidence is the commonality of dna to all life.
Life as we know it preferentially uses C12 because it takes less energy for the cell to form chemical bonds with it than with C13 or C14, and if the isotope ratio of C12 compared to other carbon isotopes is higher than the normal ratio that is an indication of biological life. I don't think it would be a slam dunk for life by itself, but it would certainly be intriguing evidence.
it would be nice if there was some research to go with this.
OTOH, it seems C12 would be used regardless whether it came from life or not.