I suspect that is is possible to quantify these effects. I posit that there is a "long *fat* tail" of various useful snippets of DNA, where one can place these in the order of usefulness, and the probability of the n'th such snippet falls off monotonically with n. Since it is a fat-tailed distribution, the integral to infinity doesn't converge. https://en.wikipedia.org/wiki/Fat-tailed_distribution The length of the tail for an individual is the size of the genome; the length of the tail for the species is the tail for the pool of the entire species. It is possible to discover so-called "bottlenecks" for a species in which the length of the tail for the species is only a bit larger than that of an individual -- this happens when the # of individuals becomes quite small -- a few tens or hundreds of individuals. "A 2005 study from Rutgers University theorized that the native population of the Americas are the descendants of only **70** individuals who crossed the land bridge between Asia and North America." "a bottleneck of the human population occurred c. 70,000 years ago, proposing that the human population was reduced to perhaps 10,000-30,000 individuals." https://en.wikipedia.org/wiki/Population_bottleneck At 03:52 PM 5/13/2016, Dan Asimov wrote:
What Henry says makes perfect sense, since the conditions under which some old DNA were good for might very well return at some point.
Maybe this helps explain how surprised I often am when an organism seems to mutate into a better-adapted one in a ridiculously short time.
The random mutation theory just doesn't seem to explain this, if you ask me.
--Dan
On May 13, 2016, at 8:38 AM, Henryy Baker <hbaker1@pipeline.com> wrote:
Yes. Code that is "commented out" is still left in for documentation and to provide a fall-back should conditions change which require going back to a previous method.
I suspect that the same thing is going on in the genome, where evolution plays with alternatives, but keeps the older deprecated and disabled versions around (either in this particular individual, or in the pool of genes in the entire population) as fall-backs.
At 03:29 PM 5/12/2016, Brent Meeker wrote:
On 5/12/2016 11:44 AM, Henry Baker wrote:
We've been running this evolutionary experiment with Unix/Linux/OpenWRT/... for the past 50 years, and the outcome is clear: it is nearly impossible to come up with a mechanism that enforces small DNA/RNA/kernel size.
Or to flip this around, the marginal cost of adding additional "functionality" -- especially functionality that is executed only occasionally (i.e., small *dynamic* cost) -- is almost free.
Which also means that non-functional code is also almost free and may persist indefinitely. And some code may even go from non-functional to functional and vice versa, depending on mutations.