OK, OpenMind5. I get the idea that you’re interested in a discussion of how organisms made of highly organized, highly differentiated cells, such as fish, birds and mammals, including H. Sapiens, came to be as they presently are. I appreciate you efforts to keep this thread on-topic, and will try to respond in kind.
I don’t have a firm grasp of your position, but infer from some of your posts that you believe in either evolution, or “devolution” – that is, that the present species have not always been as they are, but are either becoming gradually more organized, or less. I’m guessing you subscribe to the mainstream theory of cellular genetics, believing that the genome encoded in cells’ nuclear DNA contains all or most of the information used to build the complex collection of cells that is the organism. Please inform me if I’ve guessed wrong.
My take, gleaned from reading popular biological literature – I’m a mathematician by training and a computer programmer by occupation, with only a non-specialist’s education in the biological sciences – is described in part by
this short essay by Lyn Margulis. In short,
Quote:
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… Cilia were once free-agents but they became an integral part of all animal cells ..
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A bit more explanation is required beyond the Margulis piece. Specifically, I suspect that colonies of roughly circular bacteria entered into symbioses with more motile, spirochete-form bacteria, and perhaps other special-form microorganisms, giving rise to the first highly differentiated animal tissues. In short, I suspect that all of the highly-specialized cell forms in advanced organisms – sensory cilia, neural tissue, mitochondria – had their origins in independent, unusually-formed microorganisms. Further, I suspect that the process is slowly ongoing, that genetic information from foreign bacteria and viruses that regularly insert themselves into our DNA genome continue to introduce potentially useful traits. Like planetary accretion disks, large, advanced organisms collect and incorporate smaller, simpler organisms.
Give a bunch of 10-year-olds some Lego Technics/Mindstorm pieces, and observe how they construct a large, complicated machine. The most successful kids often do so by assembling arrays of small assemblies, playing with them to see which ones work well and work well together, then fusing them together into the final machine. I believe that nature plays in a similar way, and that we and our fellow biological organisms are the result.
