Tuesday, October 11, 2016

Extending evolutionary theory? - Karola Stotz

I will be attending the Royal Society Meeting on New trends in evolutionary biology: biological, philosophical and social science perspectives. I'll post each of the abstracts and ask for your help in deciding what question to pose to the speakers. Here's the abstract for Karola Stotz's talk on
Developmental niche construction

In the last decade niche construction has been heralded as the neglected process in evolution. But niche construction is just one way in which the organism’s interaction with, and construction of the environment, can have potential evolutionary significance. This constructed environment not just selects for, it also produces new variation. Nearly three decades ago, and in parallel with Odling-Smee’s book chapter ‘Niche-constructing phenotypes’, West and King introduced the ‘Ontogenetic Niche’ to give the phenomena of exogenetic inheritance a formal name. Since then a range of fields in the life sciences and medicine has amassed evidence that parents influence their offspring by means other than DNA (parental effects). Diverse scientists use different theoretical constructs for overlapping sets of processes, all of which show one way or another how heritable variation can be environmentally induced and developmentally regulated. Here I propose the concept of ‘developmental niche construction’ as a framework to integrate findings from fields ranging from molecular biology to developmental psychology. It elucidates how a diverse range of mechanisms contributes to the transgenerational transfer of developmental resources. This talk will explore the overall significance of these developments in the life sciences, and particularly how they advance the ongoing integration of development, heredity, ecology, and evolution.
Karola Stotz is a philosopher at Macquarie University in Sydney, Australia.

Organisms interact with, and change, their environment. This is hardly news but it's being promoted as one of the "new trends in evolutionary biology." Why?

I think I'll ask her what's "new" about this?


  1. Isn't this just Dawkins' extended phenotype? Did that idea ever gain much traction in biology?

  2. I don't think you're reading this correctly. It would appear that she's talking about the environment inducing developmental changes, so that inheritance of environment produces inheritance of phenotype. Or something.

    1. Yes. I read it as advocating classical Lamarckism. Amazing how these philosophers are able to find scientific evidence that elude biologists.

    2. As far as I understand it this is putting some things together that we do understand. There is developmental plasticity, where the environment influences the developmental program. There is niche construction, where we take into account that organisms are not passively inhabiting a static environment. And this at least theoretically means that if you have a plastic trait, which can take states A and B depending on the environmental conditions and the effect the organism has on the environment differs between A and B, in such a way that the frequency at which A and B are currently expressed affects in what frequency A and B will likely be expressed in the next generation.
      There's a neat analogy with how RAM works on a computer, where bits are stored through two logic gates that without an external input create a feedback loop that maintains state.
      The key question seems to be whether there are actually species where this occurs. It's one thing to note that modern evolutionary theory allows such a mechanism and to show that there is some species in which it happens.

  3. I think this is none too clearly written. Environment can select for certain genetic variations, or influence development to produce different phenotypes from the same genotype (which in turn can set up changes selection pressures). It would help if the author clearly distinguished these processes. This talk looks like it could cover interesting things, and be accurate, but has the potential to be mainly confused.

  4. Replies
    1. Thanks. The address they give is North Ryde I didn't know if that was part of Sydney or not.

  5. I understand what she is intending to say: A species can engineer their environment, and that engineered environment becomes a selective force for future evolutionary change. Examples include the beaver: they construct ponds, and their body has evolved to live in ponds. Naked mole rats dig burrows with circular tunnels. The mole rat body is very cylindrical and so is optimally shaped for navigating their tunnels.
    So, this and other planned talks are from people who are abuzz about revolutionizing the modern synthesis (and of course would be eager to be associated with said revolution). What I don't see is anything really revolutionary to include. All of these factors are simply new data (and not-so-new data) about the modern synthesis.

    1. That makes sense. It doesn't seem particularly new.

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  7. I don't agree with the general form of the "there's nothing new here" argument in evolutionary biology, for reasons that I would explain by reference to deterministic chaos. In the 1970s, certain equations, including equations for predator-prey dynamics, were found to exhibit deterministic behavior that was nonetheless chaotic. In the predator-prey case, some values of parameters would result in a stable equilibrium, or in oscillations (think about fluctuating populations of rabbits and coyotes). But with other values, you got chaotic fluctuations with no large-scale pattern.

    This was a new discovery. But the equations themselves weren't new.

    Indeed, it must have been the case that people using these equations had stumbled on some aspects of this behavior. John Maynard Smith (who was very accessible and democratic about mixing with junior scientists at meetings) once told me that he almost-discovered chaos. He made some calculations with the predator-prey equations that showed no pattern, but he didn't know what to make of it, so he moved on. This was part of a humorous recounting of other things he failed to discover (including the neutral theory-- I don't remember what else he listed).

    There is a tendency in evolutionary discussions to assume a kind of reductionism, whereby we refuse to grant that there is anything new if there is nothing new at the level of fundamental particles or forces.

    But that is not the correct standard for novelty in science. We can have new kinds of behavior, new patterns, new levels of explanation that are meaningful and important.

    I am very unsatisfied with the arguments offered by the "extended synthesis" people. However, I don't agree that they should be evaluated by the reductionistic "nothing new here" standard.

    1. I think all of us agree that it is absolutely wonderful that biologists are making new discoveries about how species evolve and interact with their environment. The problem is that we have yet to see a valid reason for scrapping what we have already learned about how species evolve.

      If we discover a new molecule, do we throw out Quantum Physics? No. Why is that? The molecule reduces down to the same particles that were already explained by Quantum Physics. I don't know why this is a bad thing.

      The same applies to evolution.

    2. The mid-century consensus on evolution known as the "Modern Synthesis" was presented, and widely accepted, as though it were a bottom-up theory that merely follows through the implications of genetics for evolution. To contradict the theory, we are led to believe, would mean to discard basic facts and equations that are beyond question.

      The reality is different from this illusion. The actual historic Modern Synthesis was not just a compilation of unassailable facts, nor a collection of mathematical truisms. Instead, it was clearly a *conjectural scientific theory*, featuring grand conjectures that followed the demands of empirical adaptationism to conclusions far beyond what elementary facts and logic required. For instance, neo-Darwinian infinitesimalism (gradualism or micromutationism) is not a basic fact or principle of biology. Likewise, it is not a basic fact or principle that selection controls the direction of evolution, that variation is merely a source of raw materials, that mutation is random in some universal sense, that mutation and development are proximate causes, and so on. Yet these were all positions of the "Modern Synthesis". They were all conjectural-- and one might even say, ideological-- positions.

    3. One of the central tenets of the Modern Synthesis was that macroevolution is just a lot of microevolution. This is not correct for a number of reasons.

      One of them might be due to levels of sorting at the species level and this is clearly not just changing the frequency of alleles in a population. I like hierarchical theory even if it's not proven.

      The most important criticism of the extended evolution crowd is that they completely missed the real revolutions in evolutionary theory. They seem, for the most part, to be unaware of the importance of Neutral Theory and random genetic drift. They are classic adaptationists who haven't bothered to assimilate the lessons of Gould & Lewontin. They don't know about mutationism in spite of the fact that prominent scientists (hi, Arlin) have been writing about it for decades.

      When I say "there's nothing new here" I'm referring to things like epigenetics—phenomena that have been around for 30 or 40 years. Their implications for evolutionary theory have been thoroughly debated but the extended evolution crowd seems to think they've come up with something new.

      Many of these people think the "selfish gene" concept was widely embraced by evolutionary biologists but that's just not true. It's barely mentioned in evolutionary biology textbooks. This is another case of attacking a strawman and it shows, once again, that this group seems to be remarkably uninformed about evolutionary theory.

    4. Links to Arlin's guest posts here to allow convenient brushing up on a bit of mutationism would be welcome to me, and perhaps others, at this point.

    5. @Arlin:

      "For instance, neo-Darwinian infinitesimalism (gradualism or micromutationism) is not a basic fact or principle of biology."

      How is it not a basic fact that the genetic differences between species are an accumulation of singular mutation events within a given lineage?

  8. @Arlin:

    "Likewise, it is not a basic fact or principle that selection controls the direction of evolution, that variation is merely a source of raw materials, that mutation is random in some universal sense, that mutation and development are proximate causes, and so on."

    I see a lot of claims here, but not a lot of support for those claims.

    For example, why do you think that birds and mammals look different during embryonic development? I happen to think it is due to the genetic differences between birds and mammals. Do you agree or disagree?