Innovation and Speciation: pre-planning (Evolution)

by David Turell @, Monday, October 12, 2015, 18:39 (772 days ago) @ David Turell

More on 'pre-planning' information has appeared, a paper and a discussion about possible examples of speciation and epigenetic changes. There is a review of Reznick's recent continuing work on guppies and the forcing of epigenetic responses in the wild coupled with Lee Spetner's comments on this research from his 1997 book on built-in pre-planning:

"Part of Spetner's argument is that many adaptive changes we see in nature are in fact not examples of a Darwinian process of chance changes + natural selection, but instead the result of specific programming capabilities in the organism to allow it to respond to changes in the environment. Indeed, what caught my eye about the article my friend forwarded is that Spetner had discussed Reznick's earlier experiments in that very context.

"After describing two different predators of the guppies: (i) the cichlid, which prey on large mature guppies; and (ii) the killfish, which prey on small immature guppies, Spetner continues:

"Reznick and his team took 200 guppies from the Aripo [river in Trinidad] and put them in a tributary of the river that is home to the killfish but has no cichlids and had no guppies. Changes soon appeared in the newly introduced guppies. The fish population soon changed to what would normally be found in the presence of the killfish, and Reznick found the changes to be heritable.

"The full change in the guppy population was observed as soon as the first samples were drawn, which was after only two years. One trait studied, the age of males at maturity, achieved its terminal value in only four years. The evolutionary rate calculated from this observation is some ten million times the rate of evolution induced from observations of the fossil record [Reznick et al. 1997].

"Reznick interpreted these changes as the result of natural selection acting on variation already in the population. Could natural selection have acted so fast as to change the entire population in only two years?

"Spetner goes on to argue that the adaptive change observed in the guppies is more likely the result of a programmed response to environmental change, and provides several examples of such changes in other species.

Comment: Reznick is finding rapid (one year) changes. Behe has identified a true Darwinian change:

"There are no doubt quite a number of legitimate, confirmed examples of random mutation + natural selection producing an important biological effect. For example, I think Behe's review of malaria/sickle cell trait is a legitimate example of Darwinian evolution in action. And the circumstances of that example are rather telling: (a) large population size, (b) meaningful amount of time, (c) very strong selection pressure, (d) and change that can be caused by one or two single-point mutations."


Reznick article:

"Our research shows that these fish adapted to their new habitats in less than one year, or three to four generations, which is even faster than we previously thought,” said Gordon, who is now at the University of Jyvaskyla, Finland, and is a postdoctoral researcher funded by the Academy of Finland.

"The findings, which appeared online Aug. 19 in the Proceedings of the Royal Society B, show how real time evolution can be resolved into differences among fathers in siring sons, which could be attributed to how successful the father is in finding mates or how long he lives. It also shows how evolution can link these differences to heritable individual attributes.

“'People think of evolution as historical. They don't think of it as something that's happening under our nose. It is a contemporary process. People are skeptical; they don't believe in evolution because they can't see it. Here, we see it. We can see if something makes you better able to make babies and live longer,” Reznick said"

Comment: No question that random chance mutation/natural selection occurs, as above, but it is not present enough to drive evolution in the time scales we know.

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