Tuesday, May 15, 2018

Controversial Ideas in Evolutionary Biology


Jeremy Fox over at Dynamic Ecology recently conducted a poll on controversial ideas in ecology. As example, some of the most controversial ideas turned out to be:

1. Species interactions are typically stronger and more specialized in the tropics.

2. Local diversity is declining in most or all localities

3. Species’ poleward geographic range limits typically are set by abiotic factors, not species interactions.

Jeremy contacted Dan Bolnick and I and suggested the perhaps it would be interesting to do a similar poll for evolutionary biology. We agree. For starters, we would like to get your opinion from the comments section on this post to select a series of questions for use for the formal poll. As examples, I am going to here suggest a few questions of the sort and form that would work well for a survey.

1. To a first approximation, neutral processes can be ignored as an explanation for organismal trait variation.

2. To a first approximation, neutral processes can be ignored as an explanation for speciation.

3. Evolutionary constraints are a strong influence on short term evolution.

4. Evolutionary constraints are strong influence on long term evolution.

5. Gene flow generally constrains adaptive evolution.

6. Character displacement is an important force in trait evolution.

7. Reinforcement is an important force in speciation.

8. Sympatric speciation is very rare.

Please suggest some more controversial ideas in the comments below. If you are curious about the survey to come, here is some text from the Dynamic Ecology poll, modified slightly for the present context.
Scientific controversies provide a fascinating window into the collective scientific process. The cartoon idealized image of science is a rigorous process, conducted by objective individuals, that converges on the truth. Which makes it mysterious why there would ever be scientific controversies, as opposed to mere uncertainty due to lack of evidence.
But for scientific controversies to give insight into how science actually works, you have to know which scientific ideas actually are controversial, or to what extent they’re controversial. That’s not always easy to figure out, even for scientists themselves! For instance, the scientists who publish on an idea generally are only a minority of the scientists with an opinion on the idea, and not a randomly-sampled minority. So you can’t always read the literature and tell the difference between, say, an idea that splits scientific opinion down the middle, and an idea on which most scientists believe X but a vocal minority believe not-X (see here and here for discussion).

Hence this poll! It will list a number of controversial or possibly-controversial evolutionary ideas. Readers will then indicate if they think each idea is definitely false (“1”), definitely true (“5”), or somewhere in between.
Each idea will be stated briefly, without caveats or elaboration, the way it might be summarized in a textbook or in the beginning of a paper. That’s the only practical way to poll on this. Plus, arguably the reason why evolutionary ideas become both widespread and controversial is by getting stripped of details, nuance, and caveats.


  1. Glad you're doing this, this should be fun and interesting.

    Some suggestions that might not be good (since they're coming from a non-evolutionary biologist):

    "macroevolution is nothing but the cumulative effects of microevolutionary forces"

    "local adaptation is common" C'mon Andrew, you of all people have gotta poll on that one! :-)

  2. "Kin selection and group selection are just two different mathematical ways to describe basically the same thing"

  3. "negative frequency-dependent selection is commonplace in natural systems"

    "negative frequency-dependent selection is a common driver of the process of speciation"

    "magic traits are commonplace in natural systems"

    "magic traits are a common driver of the process of speciation"

    "the direction and magnitude of evolution is often/usually predictable, given knowledge of the selection acting"

    "parallel evolution is common and expected, given parallel replicate conditions"

    "humans are still evolving in measurable and potentially important ways"

    "the Darwinian paradigm / Modern Synthesis needs to be replaced with a new paradigm"

    "the emergence of human-level intelligence was likely, once self-replicating life subject to the laws of Darwinian evolution had begun; i.e., there is a tendency for the evolutionary process to generate increasing complexity over time"

  4. "Broad-scale evolutionary patterns can often be successfully understood without specific knowledge of the underlying genetics"

    "Natural selection leads to organisms that appear designed to maximise something"

    "Inclusive fitness theory is a useful paradigm for evolutionary biology"

    "The key insight of Darwinism is to explain organismal adaptation"

    An old one: "Punctuated Equilibrium is a better way of describing macroevolution than Phyletic Gradualism"

  5. Selection can operate at higher levels than populations (i.e. species selection)

    Higher diversity in the tropics is explained by faster diversification rates

    Diversity is bound by ecological limits on continental scales (Am Nat debate)

    Ecological limits on clade diversity exist

    Speciation and extinction rates can be estimated using molecular phylogenies

    1. +1 to including a question on ecological vs. evolutionary limits to continental scale diversity, since we polled on that one too. Very curious if that one would get a different mix of answers on an evolution blog.

  6. This comment has been removed by the author.

  7. Species are natural entities

    1. Yes please. In fact I would love a poll of scientists about species alone. There was a first cut here:

      Pušić, Bruno, Pavel Gregorić, and Damjan Franjević. 2017. “What Do Biologists Make of the Species Problem?” Acta Biotheoretica 65 (3): 179–209. https://doi.org/10.1007/s10441-017-9311-x.

      but it was restricted in its scope and too philosophical IMO. [Disclaimer: I was a reviewer]

  8. "Non-genetic inheritance is of limited importance for understanding evolution"
    "Eco-evolutionary feedbacks driven by rapid evolution are common"
    "Current coadaptations arose from previous coevolution sensu strictu"
    "The concept of semiotic information is under-appreciated in evolutionary theory"
    "Ecology and evolution are distinctive enough to warrant independent study (and blog posts)"

  9. Niche construction and/or extended phenotype

  10. "transgenerational epigenetic effects invalidate the standard model of evolution"
    "transgenerational epigenetic effects are a specific type of maternal/parental effect"
    "inheritance of epigenetic effects is evidence that evolution is Lamarckian and is incompatible with Darwinian evolution"

  11. Niche divergence is responsible for the high diversity of tropical areas

  12. "Parallel natural selection is an effective driver of speciation"

    "Case studies on the genetic basis of adaptation strongly support predictions made by Fisher's (1930) Geometric Model of the process"

    "Most instances speciation for the foreseeable future will occur in response to habitat-modification by humans (e.g., urbanization, habitat fragmentation)"

    "Niche dimensionality, or habitat complexity, is an important component of the process of adaptation"

    "We have learned just about everything there is to learn about 'big picture' processes in speciation, only small details remain"

    "Speciation occurs more rapidly in the temperate zone than the tropics, and this is caused by differences in the degree of ecological opportunity"

  13. "Inference divergence times of most clades should be based solely on the fossil record; molecular clocks are too unreliable."


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