Posted: Aug 29, 2010 8:20 am
stevebee92653 wrote:Thanks for the rare intelligent answer and discussion. I really wish more people here could discuss as you have. This really is such a fun and fascinating subject. Discussing it should be open and respectful. But oh well.
Strange how you have failed to answer multiple serious posts in every thread you engange in, including several in this very thread. Oh well indeed.
You run into HUGE problems right at the start. Your explanation is clear, but not correct. The common ancestor to all tetrapods with the visual system you example, also had to evolve ALL of the other organs and systems common to all tetrapods.
Yes, it propably did. However, the evolution of all of these organs started all the way back when multicellularity started evolving. I have already in this very thread given you an account of how this could have happened, and other people have been kind enough to supply you with the genetic evidence of genes extant in modern but "simpler" multicellular organisms like sponges, homologous to genes found in organisms like humans and fish. Strange how the homologies between the genes in all the various organisms which we have sequenced the genomes of, fit perfectly on a hierarchical, branching tree of life, in total agreement with the fossil record.
Hepatic systems, multi-chambered heart/lung/blood/blood vessel/brain controller/cardiac muscle systems, pancreas, gastro-intestinal system, auditory, and on and on, all in one species. You can't simply choose to isolate and discuss one system without addressing all systems. Do you actually think all systems extant and common to all tetrapods evolved in that one single species CA?
Yes and no. Once again you are comitting the fallacy of "the false dilemma" and "poisoning the well". Once again we catch you intentionally making false claims about evolution and then proceeding to erect specious fantasist barriers which evolution must overcome before you are satisfied. We aren't falling for this stupid trick.
So apparently we must once again inform you that your account given above is factually incorrect. Since it does not represent the sequence of events that led to the development of all those listed organs, it does not represent a problem for evolution.
No, all of those systems would not have to spontaneously develop at the same time in one single population of a species. When all of those systems started developing in whatever multicellular organism they come from, they didn't resemble or function in the way your listed modern counterparts did. Multichambered hearts didn't suddenly pop into existence from one generation to the next.
There were muscles and circulatory systems before there were hearts, for example, as explained before.
Now we must multiply everything that so that all CA's of all modern groups must have evolved all systems common and extant to all species in each CA's descendant groups.
No. This is false. Many of your listed systems only evolved once, or maybe a few times, and spread through lineages into all life extant today. They do NOT have to develop at the same time, in multiple species.
All multicellular organisms that exist on the planet today have a multicellular, last universal common ancestor(LUCA) from which we all, ultimately derive. All of the systems and organs present in all of life today, have simpler primordial ancestors in this LUCA, from which they all, ultimately developed. They didn't all have to develop at the same time, and they didn't all have to resemble their mordern counterparts when they first started developing. Some of the systems are obviously strongly related and did develop simultaneously, like muscles with circulatory systems.
There is vast litterature on the subject, so how you can so consistently misrepresent it and get it wrong is an achievement in itself, when you constantly claim you have read it. This leaves the only obvious conclusions that you are intentionally lying and full of shit.
Your problem is you isolate one single system, vision, and tell me that that single CA spread that one system to all future tetrapods.
It's not a "problem", it happened. Get over it.
You totally ignore the fact that there are many systems to deal with in many different species groups. For example, vision had to evolve independently in each one of those SINGLE species common ancestors to all eyed groups of species.
There is no magical barrier preventing this from happening. Many species developed vision independently, yes. Many later organisms inherited vision from these earlier, simpler species. You haven't said anything remotely problematic for evolution here.
According to you, the approximately 36 phyla would each have to have their own single CA, and each single CA would have to evolve all of the organ/systems extant and common to that phylum. If that was not the case, then you run into the problem again of multiple species evolving multiple organs\systems and then having to somehow spread those systems around to other species. And then getting all of those organ/systems, that evolved in multiple species, tucked into that one common ancestor.
No steve. Once again, poisoning the well and false dilemma.
The different phyla have common ancestors from which they all derive and from which all the organs and systems they all possess, ultimately derive. The systems from which they derive in their ultimate origin could very well have served different purposes in their universal common ancestors. Some of the systems could have and propably did develop multiple times. Others didn't.
If you disagree, pencil out a diagrammatic tree and try and track where the organs and systems would go. You will get stuck quickly.
Done.
Hearts and circulatory systems can pretty much be replaced with any modern organ and simpler ancestral versions. No magical barrier or impossible to overcome path for evolution. It makes perfect sense.