Posted: Aug 28, 2010 9:08 pm
by stevebee92653
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.
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. 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?
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. Your problem is you isolate one single system, vision, and tell me that that single CA spread that one system to all future tetrapods. 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. 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.
If you disagree, pencil out a diagrammatic tree and try and track where the organs and systems would go. You will get stuck quickly.
BTW, of course you realize that the ISP thing is Tongue In Cheek. I placed "TIC" twice in the vid in case someone thinks it's serious. But the point of the vid IS serious.