More Recent Comments

Thursday, August 22, 2019

Reactionary fringe meets mutation-biased adaptation.
7. Going forward

This the last of a series of posts by Arlin Stoltzfus on the role of mutation as a dispositional factor in evolution. Arlin has established that the role of mutation in evolution is much more important than most people realize. He has also built a strong case for the influence of mutation bias. How should we incorporate these concepts into modern evolutionary theory?

Click on the links in the box (below) to see the other posts in the series.



Reactionary fringe meets mutation-biased adaptation.
7. Going forward

by Arlin Stoltzfus

Haldane (1922) argued that, because mutation is a weak pressure easily overcome by selection, the potential for biases in variation to influence evolution depends on neutral evolution or high mutation rates. This theory, like the Modern Synthesis of 1959, depends on the assumption that evolution begins with pre-existing variation. By contrast, when evolution depends on the introduction of new variants, mutational and developmental biases in variation may impose biases on evolution, without requiring neutral evolution or high mutation rates.

Thursday, August 15, 2019

Reactionary fringe meets mutation-biased adaptation.
5.5 Synthesis apologetics

This is part of a continuing series of posts by Arlin Stoltzfus on the role of mutation as a dispositional factor in evolution. In this post, Arlin explains how defenders of the Modern Synthesis react in the face of serious challenges to the theory that was formulated in the 1940s and 50s. Rather than reject the theory, they engage in various forms of "synthesis apologetics."

Click on the links in the box (below) to see the other posts in the series.




Reactionary fringe meets mutation-biased adaptation. 5.6 Synthesis apologetics
by Arlin Stoltzfus

Tuesday, August 06, 2019

Reactionary fringe meets mutation-biased adaptation.
5.4. Taking neo-Darwinism seriously

This is part of a continuing series of posts by Arlin Stoltzfus on the role of mutation as a dispositional factor in evolution. In this post Arlin discusses his view of neo-Darwinism and why it is inconsistent with macromutations and lateral gene transfer. He equates neo-Darwinism with the Modern Synthesis (1959 version), a comparison that might be challenged. Click on the links in the box (below) to see the other posts in the series.




Reactionary fringe meets mutation-biased adaptation. 5.4. Taking neo-Darwinism seriously
by Arlin Stoltzfus

The Modern Synthesis is often described as the result of combining Darwinism and genetics. This description, in my opinion, is concise and historically accurate: the Modern Synthesis of 1959 is a sophisticated attempt to arrange the pieces of population genetics to justify a neo-Darwinian dichotomy in which variation merely supplies raw materials, and selection is the source of initiative, creativity and direction.

Monday, August 05, 2019

Religion vs science (junk DNA): a blast from the past

I was checking out the science books in our local bookstore the other day and I came across Evolution 2.0 by Perry Marshall. It was published in 2015 but I don't recall seeing it before.

The author is an engineer (The Salem Conjecture) who's a big fan of Intelligent Design. The book is an attempt to prove that evolution is a fraud.

I checked to see if junk DNA was mentioned and came across the following passages on pages 273-275. It's interesting to read them in light of what's happened in the past four years. I think that the view represented in this book is still the standard view in the ID community in spite of the fact that it is factually incorrect and scientifically indefensible.

Friday, August 02, 2019

Reactionary fringe meets mutation-biased adaptation.
6. What "limits" adaptation?

This is part of a continuing series of posts by Arlin Stoltzfus on the role of mutation as a dispositional factor in evolution. In this post Arlin discusses the role of adaptation and what determines the pathway that it will take over time. Is it true that populations will always adapt quickly to any change in the environment? (Hint: no it isn't!) Click on the links in the box (below) to see the other posts in the series.




Reactionary fringe meets mutation-biased adaptation.
6. What "limits" adaptation?

by Arlin Stoltzfus
According to the hatchet piece at TREE, theoretical considerations dictate that biases in variation are unlikely to influence adaptation, because this requires small population sizes and reciprocal sign epistasis.

Yet, we have established that mutation-biased adaptation is real (see The empirical case and Some objections addressed). If theoretical population genetics tells us that mutation-biased adaptation is impossible or unlikely, what is wrong with theoretical population genetics?

Adaptation, before Equilibrium Day