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New Definition of Evolution by Natural Selection

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The third thing (beyond density-dependence and mating markets) that I have expanded on since I wrote the book on Darwinian Sociocultural Evolution a decade ago is the proposed new definition of evolution by natural selection.

The definition there was:
“Microevolution by natural selection is any change in the inductive control of development (whether morphological, physiological or behavioural) by ecology and/or in the construction of the latter by the former which alters the relative frequencies of (genetic or other) hereditary elements in a population beyond those expected of randomly chosen variants.” In my haste to include the ecologically inductive and developmentally constructive pathways, I omitted the traditional hereditary (e.g. genetic mutation or recombination route)! In Blute (2017) I explained how all of these are possible but did not include a definition. So in Blute (2019) I offered a new, new definition, most concisely:

“microevolution by natural selection is any change initiated by inheritance, ecology, or development that alters the relative frequency of (genetic or other) hereditary elements in a population beyond those expected or randomly chose variants.”

Blute, Marion. 2017. “Three Modes of Evolution by Natural Selection and Drift: A New or Extended Evolutionary Synthesis.” Biological Theory 12(2): 67-71.
Blute, Marion. 2019. “A New, New Definition of Evolution by Natural Selection.” Biological Theory 14(4): 280-81.

Written by Marion Blute

June 2, 2020 at 2:28 pm

Mating markets

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Darwinian Sociocultural Evolution Chpt. 4 was on social interaction within a population – competition, conflict and cooperation. After general discussions of relevant evolutionary principles, these were applied to gender differences and relations. The latter discussion was expanded on in Blute (2019).

Rather than males as reproductive parasites of females (as has often been thought, most likely at high densities relative to resources where the most common female ‘quality’ strategy would be most beneficial) or even females as reproductive predators of males (most likely at low densities where the most common male ‘quantity’ strategy would be most beneficial), the approach suggested that the sexes have somewhat different naturally-selected frequency and/or quality ecologically-oriented strategies and that sex is trade in these. The sexes have what economists call different “comparative advantages” compensating for the up to two-fold cost of sex. Males and females (or male and female functions in hermaphrodites) have sex i.e. then trade because males including females among their offspring and females including males among their offspring bet-hedges under uncertainty – reducing the risk of extinction for families, populations or species. Protecting the portfolio is the same reason why humans invest in index funds rather than trying to pick stocks or dollar cost average rather than trying to time markets. Sexual competition and selection on the other hand is conflict over the profits of that trade.

Because natural selection comes logically, historically and developmentally before sexual selection, the table in the 2019 article (see below) more clearly illustrates the consequences of the results of natural for sexual selection than did Table 2. on p. 100 of the book. For example, in line 1 below, if males are naturally selected to be more frequent and females to be higher quality (i.e. have a higher per capita cost), then the results for sexual selection would be males intrasexually selected (male-male competition for mates and/or gametes) and females intersexually selected (active choice for a male mate and/or gametes). Table 1 as a whole illustrates how combining quantity and quality approaches based on natural selection can explain the resulting conventional sex roles, the sex-role reversed, inter as well as intra sexual selection, and passive as well as active choice. As well, the approach implies that sexual selection could equilibrate the sex allocation instead of Fisher’s sex allocation principle and that Mayr’s species definition could be made explanatory. The latter can be restated as “a species is a biological, specifically a mating market, one isolated from other such markets”.

Table 1. Ecologically oriented, naturally selected frequency and mean quality of males and females and their implications for the directions and forms of sexual selection*

Males          Females      Direction and forms of sexual selection

M     Qm      F     Qf            

h      l          l      h          Males intrasexually selected, Females intersexually selected (active choice)

l       h         h     l           Females intrasexually selected, Males intersexually selected (active choice)

h      l          h     l          Both sexes mate multiply, Little or no sexual selection

l       h         l      h         Pair bonded, Little or no sexual selection

h      h         l      l          Males intra & intersexually selected (female passive choice)

l       l          h     h         Females intra & intersexually selected (male passive choice)

*M frequency of males, Qm mean quality of a male, F frequency of females, Qf mean quality of a female, h high, l low
Blute, Marion. 2019. “Mating markets: A naturally selected sex allocation theory of sexual selection.” Biological Theory    14(2) 2019: 103-111.

Written by Marion Blute

May 10, 2020 at 2:53 pm

Density-dependent natural selection may have implications for the coming decline side of the COVID-19 pandemic

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Chapter 3 of Darwinian Sociocultural Evolution on “Necessity: why did it evolve” discussed principles of evolutionary ecology, notably density dependence relative to resources in section 3.3.1., and applied them illustratively to the sociology of science. Subsequently Blute (2016) reviewed the history of, and greatly extended the theory. The extensions included its applicability to selection in space and/or time, to somatic functions as a cause and not just an effect (as in Fisher’s sex allocation theory for example), and to selection within and between, not just growing populations, but also declining ones. These may have implications for the coming declining side of the COVID-19 pandemic.

Where/when density measured in cost per capita relative to resources is low within a population, or in growing populations with a history of catastrophes, natural selection favours spending on consumption (eating and excreting) whereas where/when it is high or in declining ones with a history of bonanzas, selection favours investing in digestion (breaking down and building up). What should be built up? In a homogeneous environment it is mechanisms of social interaction whether cooperative, antagonistic or a mixture of both but in a patchy environment it is mechanisms of dispersal in time (maintenance), in space (motility), and/or in niche (mutability) – the 3 M’s. Similarly, low density measured in frequency or in growing populations with a history of catastrophes, natural selection favours production (many small offspring) whereas high densities or in declining ones with a history of bonanzas, selection favours “reproduction” (fewer larger offspring, ones capable of social interaction or their own 3M’s).

Both these somatic and reproductive distinctions are quantity versus quality ones with the former in each case depleting and degrading the external environment while the latter depletes and degrades the internal environment. As well, the former in each case is associated with a small size because of the disproportionate surface to volume ratio there and the latter of each associated with a large size because of the disproportionate volume to surface ratio there. Under the simplest set of conditions if both somatic and reproductive functions utilize the same or positively correlated resources and the two functions interact synergistically, then at low densities the more one consumes the more one can produce and vice-versa whereas at high densities the more one digests the more one can reproduce and vice-versa.

What then of COVID-19? Our culture is coevolving in interaction with their genes (gene-culture or culture-gene coevolution, between species in this case) and our culture has evolved favouring social distancing etc. in some places – depleting viral resources and causing a levelling off and decline in the viral population(s).  But our culture is now on the edge of reversing itself at least somewhat. What are the implications of that for the virus? Given that surely humans are a heterogeneous environment, selection on the viruses should then favour:
i) maintenance: those which live longer (e.g. making the recovered or infected but symptom free contagious for longer)
ii) motility: those which move further (e.g. placing themselves in small droplets which disperse further rather than just in large drops which tend to fall) and/or
iii) mutability: those which increase their blind mutation rate seeking a new niche (e.g. infecting organs other than respiratory systems such as kidneys, nervous systems etc.)

It is at least possible therefore that changes in their genes and not just in our culture will in the future be contributing to one or more further spikes in the pandemic until a vaccine is widely available or until the 70 or 80% infection rate required for herd immunity is reached.

Blute, Marion. 2016. “Density-dependent selection revisited: Mechanisms linking explanantia and explananda.” Biological Theory 11(2) 113-121.

Written by Marion Blute

May 3, 2020 at 4:22 pm

What would I change?

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I have sometimes been asked what would I change today in the book I published a decade ago on Darwinian Sociocultural Evolution: Solutions to Dilemmas in Cultural and Social Theory? Not a lot actually in the sense that it is largely free of those little flaws of typing, spelling, miswordings etc. thanks to Cambridge’s excellent text editor and two friends – Gail Greer and Hank Jerzy. As Hank put it then “reading for that is a different kind of reading”.

Of course Tang Shiping in the acknowledgments should have been Shiping Tang and there is the spelling mistake on the first page of the introduction – “complemented” for “complimented”! There are a few others. The caption for the diagram on p. 39 should have read “family tree of world’s language families” not of world’s languages; on p. 42 Darwin’s tree did not show several branches going off from a single point, only two; on p. 122 a space instead of an h was inserted in “that”; and on p. 77 the brackets on the equation for the logistic function ended up slightly misplaced – they should have been as in Blute (2016).

With respect to the chapter on “history: where did something come from” there has subsequently been a huge expansion by many investigators of applications of phylogenetic methods borrowed from biology to social and cultural subject matters. Many of these were reviewed in Blute & Jordan (2018). Together they more than confirm the thesis that the subject matters of the social sciences do indeed descend with modification. Similarly, I see no reason today to change the balanced approach I took on major issues – history and necessity, cooperation and conflict, the ideal and the material, reason and reinforcement, the subjective and the objective, culture and social structure, and the biological and the sociocultural. I have however subsequently expanded on the substance of three points. As is often said, one sees only through a glass darkly (at first at least). The three are density-dependent selection, sexual selection and the proposed new definition of evolution by natural selection. I intend to briefly explain each of these extensions in subsequent posts.

Blute, Marion. 2016. “Density-Dependent Selection Revisited: Mechanisms Linking Explanantia and Explananda.” Biological Theory 11(2) 113-121.
Blute, Marion & Fiona M. Jordan. 2018. “The Evolutionary Approach to History: Sociocultural     Phylogenetics.” In Rosemary L. Hopcroft (Ed.) The Oxford Handbook of Evolution,     Biology, and Society. Oxford University Press. Chpt. 28: 621-640.

Written by Marion Blute

April 28, 2020 at 3:47 pm

The Advantages of Specialization Can Compensate for the Two-Fold Cost of Sex

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In July I organized a session titled “Let’s talk about sexual selection” for the meeting of the International Society for the History, Philosophy and Social Studies of Biology held this year in Oslo, Norway. I gave a paper in the session titled “The puzzle of what compensates for the two-fold cost of sex solved: The advantages of specialization”. The talk took a brief point from a paper I recently published in Biological Theory on “Mating markets: A naturally selected sex allocation theory of sexual selection” – that the advantages of specialization can compensate for the two-fold cost of sex – and expanded on it. I will not repeat the long abstract of the talk given here (which was slightly different than the one in the conference programme anyway), just summarize it.

It is commonly said that there is a two-fold cost of sex – variously understood as the cost of meiosis (of producing offspring related by a coefficient of relatedness of ½ instead of 1), of producing sons to females (if males contribute only genes and not material resources to offspring), or of sexual competition and selection. However, specialists are commonly more efficient in the segment of a niche that they specialize in than are generalists in that segment – a point I first made more than twenty years ago in a review of Maynard Smith & Szathmary’s The Major Transitions in Evolution in a review in the journal Politics and the Life Sciences.

Hence if a normally distributed niche is divided in two, with one of two sexes, two kinds of sexual functioning in hermaphrodites, or two mating types are specialized, with one specializing more in one side of the niche and the other in the other, and if each kind of specialist is a little more than twice as efficient in what they specialize in than are generalists in that, then the two-fold cost of sex would be more than compensated for. The specializations may be infinitely varied in different taxa but in general they could be ecologically differently specialized, one more naturally and one more sexually specialized, or both differently sexually specialized. After all, even isogametic mating types are specialized in who they mate with. In any case, the rule for two – that the two-fold cost would be compensated for if each is a little more than twice as efficient in the segment of the niche they specialize in than are generalists in that segment holds.

Written by Marion Blute

September 27, 2019 at 8:30 pm

Enriching the Cultural Evolution Project with Cognitive Psychology but . . .

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Anyone who enjoys reading ‘big picture’ books involving the behavioral and brain sciences in an interdisciplinary context will enjoy Cognitive Gadgets: The Cultural Evolution of Thinking by Cecilia Heyes. Its goal is almost, well, grandiose. It addresses what is unique about humans; distinguishing among nature, nurture and culture; a generic genetic starter kit for the latter; the distinction between social and cultural learning; and neurocognitive mechanisms – the latter being “small but important” parts of human minds including selective social learning, imitation, mindreading and language (although calling these “gadgets” almost trivializes them). This framework used strikes me as more of a combination of cultural evolutionary theory and cognitive psychology than of cultural evolutionary theory and evolutionary psychology as the author claims. I suspect that the reason for the claim as made is that putting the terms “evolution” and “psychology” together makes it impossible not to address evolutionary psychology for disciplinary reasons even though most of the discussion of the latter in the book is in fact dissenting.

I would criticize two points while still endorsing much of the project as a whole. The third section of chapter 2 claims that variants of ideas or behaviors are “unitized by common sense or folk psychology” and in section 2.3 of the target article that is said to be the “only” way. This cavalierly dismisses the work of dozens of social scientists and humanists – anthropologists, archaeologists, historical linguists and others doing research on cultural evolution. They have demonstrated, using a variety of quantitative scientific methods, that the classification of cultural traits into groups within groups is as revealing of the history of the historical relationships among them as Darwin first argued was the case for biological traits.

The second criticism I would make is of the strong distinction drawn between social and cultural learning when culture is a population of social learning events and particularly the claim that no mechanism of cultural inheritance is analogous to DNA replication. To the contrary, social learning by linguistic instruction whether oral, written, or electronic as opposed to by observation in any sensory modality is analogous to genetic transmission in a surprising amount of detail. For example, both are structurally composed of digital strings (nucleotide bases genetically and phonemes linguistically) which aid stability in transmission, larger basic units of function (codons genetically and morphemes and lexical items linguistically), and more inclusive units of each until one reaches that which can stand alone – a genome genetically or a sentence or utterance linguistically. Moreover units of function in both are said to be symbolic rather than iconic because of the arbitrary i.e. historical nature of the link between strings of symbols and what they stand for or represent. None of this should be taken to imply that the meaning of strings of symbols in either case is not enriched in other ways – by many kinds of cytoplasmic inheritance and inductive environmental influences biologically and tones, gestures, facial expressions, illustrations, emojis etc. linguistically.

Despite these and other criticism that could be made, I have no doubt that cognitive psychology will eventually add much to the cultural evolutionary project including possibly Heyes four gadgets which she presents as a program for future research.

Written by Marion Blute

June 13, 2019 at 7:19 pm

Who Needs Pragmatism? Nobody and Everybody.

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I did not pay a lot of attention to the revival of pragmatism in sociological theory in the second half of the twentieth century. One reason was I sensed some chauvinistically American nationalism after the leadership in social theory shifted to Europe in the post-Parsonian period. The implicit claim of pragmatism was “Oh, well there is an important historical tradition in social theory that is quintessentially American”.

But the major reason for my inattention was scientific. The core premise of pragmatic philosophy is that what is true is what works i.e. consequences are what matter. However, a century old philosophy is a poor substitute for the three major selectionist scientific theories – biological evolution by natural selection, individual learning by instrumental or operant conditioning, and sociocultural evolution by social learning, variation and sociocultural selection – all three of which embody that premise. These sciences share pragmatism’s premise, but they are scientific instantiations – each with a large number of related theoretical propositions, derivations, empirical support etc.

Nor did the three have their historical roots in pragmatic philosophy – if anything the reverse is the case. The early pragmatic philosophers were influenced by Darwin (see for example Nungesser 2017). In short, nobody in the social sciences needs a 19th century philosophy, but all need it in one or more of its scientific forms.

Reference:

Nungesser, Frithjof. 2017. “The evolution of pragmatism: On the scientific background of the pragmatist conception of history, action and sociality.” European Journal of Sociology 58(2) 327-367.

Written by Marion Blute

June 2, 2019 at 7:09 pm

Remembering David Hull

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This post is long overdue. David died in 2010 (see his brief biography and bibliography on Wikipedia). He was a philosopher of science, specifically of Biology, and wrote the first textbook on that – Philosophy of Biological Science in 1974. While he published much else, his magnum opus was Science as a Process: An Evolutionary Account of the Social and Conceptual Development of Science published in 1988.

Key Ideas: Science as a Process tells the story of the three schools of biological systematics vying for dominance in the 1970’s and early 1980’s – cladistics which maintained that biological classification should be strictly historical, numerical taxonomy which maintained that it should be based on overall observed similarities and differences, and those who advocated a pragmatic mixture of both and who called themselves evolutionary taxonomists. In the course of telling that story, Hull presented his evolutionary theory of science. Morphing into a sociologist, he used a variety of sociological methods including studying referees’ reports to illustrate it empirically. Science is based on curiosity (innovation), credit (descent), and checking (selection). Concepts, theories and methods in science literally evolve culturally including even by the equivalent of kin selection according to Hull.

He also took part in the lively units of selection debate in Biology over the plausibility or lack thereof of group selection. According to Hull, the debate was confused because the elements of an evolutionary process are predicated of different entities – genes replicate, organisms are selected and lineages evolve.

He is also remembered along with Michael Ghiselin for drawing a distinction between individuals and classes. Species and other higher taxa are “individuals”, not in the sense of functionally integrated organisms, but in the sense that they are branches of the tree of life – historically specific entities about which only particular statements can be made. They have an historical origin, a specific geographical distribution, and an historical end. They stand in contrast with the universally specified “classes” of traditional scientific theories, Newton’s mechanical systems for example obey certain laws whenever and wherever they are found. They did not deny that there may be such classes in biology scattered across the tree of life – laws governing small organisms with fast life cycles versus large ones with longer slower life cycles for example both of which can be found in a variety of taxa. Like his altruistic personality in general, David was proud of the fact that he and Michael never engaged in priority disputes over the individuals-classes distinction.

HIV/AIDS: As a gay man, David’s life was affected by the Aids outbreak in the west in the 1980’s. Not so well known is that he wrote Science as a Process, at nights while in the daytime nursing to the end two friends dying of HIV/AIDS. When I asked him why he did it, he said simply “they had nowhere else to go”. He regularly advised young colleagues to talk to their students about HIV. He used to say, “tell them you are not trying to stop their fun. It is just that they need to use protection until we get this thing figured out.” I have often wondered how many lives he saved indirectly that way.

Organizing & Mentoring: David did much organizing and mentoring. As well as being President of the Philosophy of Science Association for a time, while researching the history of biological systematics for Science as a Process, like the anthropologist who becomes king of the tribe he is studying, David became President of the Society for Systematic Biology! He was also a founding member of the International Society for the History, Philosophy and Social Studies of Biology, ISHPSSB or Ishkibble to insiders! Like David, it is interdisciplinary in nature – a society in which biologists, philosophers of science, historians of science and social scientists actually talk to one another about Biology and it remains my favourite society.

I had much personal experience of David’s mentoring of many younger colleagues from the first paper I sent to him based on part of my PhD thesis (by snail mail in those days). I received a prompt reply about how I got almost everything right except one thing! At various times he invited me to take part in sessions at Duke University and ISH, always followed my work with interest and comments, and I understand he wrote letters for my tenure and promotion to Associate Professor and later to full Professor. It was so characteristic of David that while a graduate student of mine, Paul Armstrong, was interviewing him for a project we were working on analysing texts and interviewing theorists on the general theories of science/scholarship that had emerged after the decline of logical positivism, a study later published in the journal Perspectives on Science, David could not resist inserting career advice for Paul!

Last Contact: My last contact with David was after the ISHPSSB meeting in Australia in 2009. He had had a fall and had not been able to go. We exchanged e-mails – he was anxious to know how everything went and all the gossip. When my monograph was coming out in 2010 I sent him the final text to read and was dismayed to soon receive a response from someone sorting out his academic affairs that he had died. That was probably the saddest day of my professional life.

Written by Marion Blute

May 5, 2019 at 7:18 pm

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Evolutionary Lessons in How to Succeed

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  1. Most cultural like most biological innovations fail (most papers that are published are rarely cited, most patents that are granted are never utilized and most new businesses and new products fail for example). As early as 1979 I gathered information supporting such generalizations from a variety of sources. The first lesson: despite all the current hype to the contrary, don’t innovate!
  2. Successful macro mutations do occur but are rarer than hens’ teeth so the second lesson is that if one must innovate, make (numerous if necessary) small changes.
  3. Most speciation is geographical – despite all the hype about the importance of becoming a world-wide competitor, the third lesson is that innovations should be geographically specific.
  4. However, there are advantages to ecological specialization. Specialists tend to be  more efficient in the segment of a niche that they specialize in than are generalists in that segment so the fourth lesson is to specialize. But in a however to the however, avoid extreme niche markets – because of sampling error, tastes there are likely to be random.
  5. Since most innovations fail, how should success be measured? Relatively of course. Finally I must admit that I have rarely taken these lessons to heart myself!

Written by Marion Blute

May 4, 2019 at 1:53 pm

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Tangled Trees?

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David Quammen book, The Tangled Tree: A Radical New History of Life was reviewed in Nature Aug. 2 by John Archibald (not incidentally the author of a book on symbiosis). It was also reviewed in the New York Times Book Review on Aug 14 by Erika Check Hayden under the title of “Uprooted”. On Aug 19, Quammen himself published an article in the New York Times Magazine titled “The Scientist Who Scrambled Darwin’s Tree of Life”.

Quammen’s book is largely about Carl Woese, the great pioneer of molecular phylogenetics, who in 1977 with coauthor Fox, made clear from their study of a component of ribosomes (protein factories in cells) that there are three not two domains of life – the Archaea in addition to Bacteria and organisms with nucleated cells like plants, animals, fungi and some unicellular organisms (Eukarya). Woese was apparently not a fan of Darwin – he commented to a prospective co-author of a book to be titled Beyond God and Darwin, “Jan, you accord Darwin so much more substance than the bastard deserves”.

Anyway, the theme of the reviews and article (and I assume of the book which I have not, or at least not yet read), is that life is better described as a “network”, a “tangled web”, or a “topiary” rather than Darwin’s tree because of the existence of horizontal i.e. lateral gene transfer (LGT ). LGT can take place by transformation (taking up DNA from the environment), transduction (a piece of host DNA carried to another organism by a virus), and conjugation (bacterial “sex” which is unidirectional). Unfortunately Hayden casually equates LGT with “swapping genes” which is exactly what it is not i.e. bidirectional rather than unidirectional. Not does its existence invalidate Darwin’s tree metaphor for evolution as these authors generally seem to think. Quammen’s article is illustrated with outrageous illustrations of what looks like an early hominid with a chicken’s head, one with a fish’s head, a human with what looks like a frog’s body between head and shoulders on top and lower legs and feet on the bottom. Perhaps we should not blame Quammen for these illustrations but the point is that because laterally transferred DNA is normally just a tiny part of the genomes of eukaryotes, the best metaphor I have seen is “trees with some cobwebs”. (In 2005 Liza Gross in PloS attributes this metaphor to Fan Ge and coauthors.)

Yet, once anisogamy (micro and macro gametes) have evolved, then sex again becomes unidirectional, i.e. from males or male functions to females or female functions. But that is unidirectional within a species – indeed the ability to interbreed after Mayr is what is most commonly said to define species boundaries. Of course Woese was right that we know very little of what went on in the early history of life. However, only if hybridization (sex between members of different species) were rampant in the Eukarya could Darwin’s trees truly be said to be entangled and despite the occasional case there is no evidence of that.

Written by Marion Blute

September 6, 2018 at 7:50 pm

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