Shermana
Heretic
Please debate the contents itself of the following peer reviewed paper, on whether the critique on Wilf and Ewens "There's plenty of Time for Evolution" has valid points or if it is misrepresenting them.
Ewert
Ewert
Please keep all responses on topic and focused on the contents itself of the peer-reviewed paper or you will be kindly reminded to stick to the subject, thank you. If you are only interested in attacking the source without addressing the actual contents of the paper, feel free to demonstrate that you don't want to discuss the paper on another thread.
Example, if you disagree with: (Page 5, top)
Ewert
Abstract
Wilf and Ewens argue in a recent paper that there is plenty of time for evolution to occur. They base this claim on a mathematical model in which beneficial mutations accumulate simultaneously and independently, thus allowing changes that require a large number of mutations to evolve over comparatively short time periods. Because changes evolve independently and in parallel rather than sequentially, their model scales logarithmically rather than exponentially. This approach does not accurately reflect biological evolution, however, for two main reasons. First, within their model are implicit information sources, including the equivalent of a highly informed oracle that prophesies when a mutation is “correct,” thus accelerating the search by the evolu- tionary process. Natural selection, in contrast, does not have access to information about future benefits of a particular muta- tion, or where in the global fitness landscape a particular mutation is relative to a particular target. It can only assess mutations based on their current effect on fitness in the local fitness landscape. Thus the presence of this oracle makes their model radically different from a real biological search through fitness space. Wilf and Ewens also make unrealistic biological assumptions that, in effect, simplify the search. They assume no epistasis between beneficial mutations, no linkage between loci, and an unreal- istic population size and base mutation rate, thus increasing the pool of beneficial mutations to be searched. They neglect the effects of genetic drift on the probability of fixation and the negative effects of simultaneously accumulating deleterious muta- tions. Finally, in their model they represent each genetic locus as a single letter. By doing so, they ignore the enormous sequence complexity of actual genetic loci (typically hundreds or thousands of nucleotides long), and vastly oversimplify the search for functional variants. In similar fashion, they assume that each evolutionary “advance” requires a change to just one locus, despite the clear evidence that most biological functions are the product of multiple gene products working together. Ignoring these biological realities infuses considerable active information into their model and eases the model’s evolutionary process.
Ewert
Please keep all responses on topic and focused on the contents itself of the peer-reviewed paper or you will be kindly reminded to stick to the subject, thank you. If you are only interested in attacking the source without addressing the actual contents of the paper, feel free to demonstrate that you don't want to discuss the paper on another thread.
Example, if you disagree with: (Page 5, top)
please explain your specific reasons.As seen in Figure*3 (a plot of Equation 10), this equation
shows a very rapid decline in active information per query as
the amount of independence is decreased. This demonstrates
that even a small amount of dependency between the mutations
causes a very sharp decline in the information extracted and
thus a large increase in the time required to reach the desired
phrase.
The Wilf and Ewens model suggests that it will take approximately 390 rounds of guessing to find 20,000 beneficial
mutations. However, even the smallest level of dependence,
with word lengths W=2, rapidly increases the time required, and
that time increases exponentially as the word length increases.
Last edited: