Is the Dominant Pattern of Evolution Reductive or Additive?

Continuing the discussion from Michael Behe’s Darwin Devolves Topples Foundational Claim of Evolutionary Theory:

A masters (student?) in ecology in stickleback has raised some interesting questions worth engaging.

@Dan_Durston you might want to begin by defining the quish terms here, like “function,” which do not have a fixed meaning. It would be interesting also to understand what you made of the many gain-of-function mutations we know about, and how the streetlight bias makes it easier to detect loss of function mutations, and therefore dramatically inflates our estimate of their proportion.

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This seems akin to saying the net motion of your car is to stay parked in the garage. We seen others (EricMH) make a similar argument that net information can never increase, but this depended on a misunderstanding of the biological application. In your example where you observe loss of function, the obvious question is, “Does this loss of function correspond to a gain in fitness relative to the local environment?”


The losses in genetic function I refer to certainly do correspond to gains in fitness. This is the same as what Behe says in his book with his first rule of adaptive evolution (“Break or blunt any functional coded element whose loss would yield a net fitness gain.”)

If maximizing fitness is what we’re trying to explain, then these are examples. But Darwin argued for much more than simply “fitness is maximized”. He argued that his mechanism can explain the existence of the highly sophisticated/functional genomes we see today. Examples where fitness increases but genetic function decreases are certainly examples of adaptive evolution, but they are not demonstrations of increased genetic function, and thus do explain the large differences in genetic function between say a prokaryote and a camel. To explain that, we need to see that increasing genetic function is the overall pattern.

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@Dan_Durston, thank you for joining us. Can you explain what you mean by these terms?

  1. Information
  2. Loss of information
  3. Gain of information
  4. Genetic Function

As a calibration point, it would helpful to know how you interpret the ENCODE data. Does this project demonstrate most the genome is functional? By what definition?


We’d love to help you make sense of it. Just share your thoughts on it, perhaps even from you work on fish.

Reading this topic, I thought of useful analogies for applying the appropriate statistical approach.

Acorns: The overwhelming dominant pattern of acorns is that they fail to give rise to a new oak that makes more acorns. I’ve got a healthy mature oak that produces hundreds of pounds of acorns most years. Probably 100K+ acorns over the course of a few years. Yet none of the acorns produced has managed to grown into a mature tree (actually, any tree over 1-2 feet tall).

The question is not so much what is the dominant pattern, but what is the actual pattern. The fact that the overwhelming majority of acorns fail to produce mature trees does not mean that oaks don’t propagate.

For the reductive vs. additive question in evolution one needs to understand both the rates & magnitudes of events, plus the mode of propagation.


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