Betty, sorry, I forgot to address you on the last post.
I do think the Brownian motion model is good for most "random" systems in biology. In a large system, say the size of a few cells in an organism, Brownian motion provides most of the "randomness" with a small kick from QM (radioactive decay leading to mutation). Selection is more of a "relative independence" type of thing. Selection criteria for a group of individuals need not have any relation to the chemistry of the cell (lions and tigers and bears eating antelope, for example.)
"
. . . Selection is more of a "relative independence" type of thing. Selection criteria for a group of individuals need not have any relation to the chemistry of the cell (lions and tigers and bears eating antelope, for example.)"
I agree with this too. This leaves us with at least two types of randomness to consider when discussing the history of life on earth as explained in biological processes; a "Brownian Motion" type when dealing with the origins of life, i.e. "abiogenesis," and a "relatively independent" type when dealing with natural selection.
But I would like to separate something here from within the process of natural selection, namely; "random mutations." I would think the "Brownian Motion" model is applicable here too, but I'll await comments. One thing I am wondering about is the role "inert information" at the microbiological level may play in what we consider "random" mutations. Bio-semiotics is dealing with this problem right now, but they are only able to address it theoretically because
the "inert" information within the human genome is apparently stored in retroviruses within RNA, at least that seems to be the current opinion. I emphasized the last statement in recalling tortoise's
post #293 in which he raised the issue of the "theoretical nature of bias" in applying randomness, which I believe now becomes relevant when trying to assess the "random" nature of mutations that may in fact follow a more predictable,
deterministic?, pattern than we have hitherto entertained. I still think this keeps the "Brownian Motion" model intact, but how are we to entertain "bias" within all of this?
I'm not in a rush for any response. I'm just dropping in during a work break right now and I probably won't be able to get back to this until tonight.