A little acid... is all it takes... (Evolution)

by dhw, Friday, January 31, 2014, 14:03 (3947 days ago) @ xeno6696

Matt: It seems that putting adult human cells... under selective pressure puts them into a state that they can become any other kind of cell. 
This directly undermines the idea that natural selection is incapable of massive, rapid changes in the development of an organism. If, given enough pressure, a bone cell can be coaxed into a neuron, or skin cell, or an eye cell... then it stands to reason that the same plasticity applies to the entire organism.-DAVID: I think this is a misuse of the term natural selection. The environment, not NS, acts on the organism which changes by this mechanism. NOW natural selection steps into determine if the change is sufficient for survival. NS is the end judge of the whole process and can only act on what is presented to it.-MATT: I think that our understandings of natural selection are different. If you'll entertain me for a moment--evolution is a process. And (I'm getting ready to post a slew of controversial posts) a primary aspect of that process is the organism's response to environmental change. The thing that *makes* natural selection important, is the fact that it replaced the notion that "all things appeared in the forms they are in" with "All things are the way they are because of a stimulus-response interaction with the environment." 
Basically, natural selection stops being "Natural Selection" if you attempt to logically separate the environment from the response. So the way I look at it, natural selection is the act of organisms adapting to changing environments. So putting cells in an environment that causes "stress" (or selection pressure) and that environment causes them to revert to a state where they're capable of becoming ANY kind of cell... this is groundbreaking stuff. and this paper describes to me, for the first time--the secret sauce of natural selection. Though, as a hint to my future posts, humanity owes much to natural selection, but the crazy-in-geological-terms speed of our advancement has alot to do with three other kinds of selection: Group selection, Epigenetics, and symbolic.-This is a very exciting development, and I'm looking forward to your controversial posts, but am apprehensive that we are once again going to be drawn into a discussion on the meaning of Natural Selection. I do hope this is not central to your future posts! We had a long debate about it some time ago, and I really thought we'd settled it. How can your definition ("the act of organisms adapting to changing environments") be equated with "natural selection"? Nature can only select from what already exists, and it does so by allowing some organisms to survive and killing off others, in accordance with their existing ability to cope with their respective environments. I am 100% with David on this: NS is the final stage in the process of evolution, and it does not CAUSE adaptations or innovations. These are CAUSED by interaction between cells and their environment, and NS determines what responses will survive.-What I hope we will focus on in our discussions are the implications of the "acid" discovery. Tony has pointed out that "it does not explain the innovation of new 'designs' that would require an influx of new information". Without innovation, evolution would be stuck with bacteria. Clearly the cell has the potential not only to adapt (which bacteria do most successfully) but also to innovate, and perhaps the "rewinding" process described here can be taken as confirmation that evolution has been driven by the inventive intelligence of cells and cell communities. As environments changed, so cell communities came up with new methods of mastering them, and Natural Selection determined which methods (embodied in new organs) would survive. "Rewinding" adult cells sounds like a way of restoring them to their state of potentiality before they came up with bones, neurons, skin, eyes etc., though of course once the invention had succeeded, it took its place in the established repertoire.