Teaching Evolution = changes in the diversity of forms (of something) over time

Notes from presentation, 10/11/2006.


Studying biological evolution requires us to note six features:

– There is a diversity of forms and patterns in that diversity

– There is a geological record and patterns in this record

– Organisms tend to be adapted to their environment

– Characters or features of organisms are part of an organized form which is developed anew each generation

– There is change over time and sometimes improvement over observable time.

– All life and change occurs at some place/ in some circumstances  Read more of this post

A constructionist perspective on the structure of ecological complexity, follow-up questions

It would be interesting to investigate why the constructionist perspective on ecological complexity (see below) is overlooked. One answer is that people haven’t come across what has been written on that perspective by me and others. But I’m more interested in why hasn’t it been discovered and annunciated by others for themselves and why they don’t discuss its implications once they know about it. This post presents the idea again (quoting from a 2010 post, which draws from Taylor 2005, 3-17) then reviews Robert May’s response to it over the last 30 years. Read more of this post

Biology as Politics: The direct and indirect effects of Lewontin and Levins

Introduction to my essay review of

Biology Under the Influence: Dialectical Essays on Ecology, Agriculture, and Health, by Richard Lewontin and Richard Levins, Monthly Review Press, 2007

In “A Program for Biology,” one of this collection’s thirty-one essays, the Marxist biologists Richard Lewontin and Richard Levins (hereon: L&L) list recent “big mistakes” in scientific approaches to complex phenomena: “the green revolution, the epidemiological transition [from infectious to chronic diseases], sociobiology, the reification of intelligence testing, and the current fetishism of the genome.”  They attribute such mistakes to the “posing [of] problems too narrowly, treating what is variable as if it were constant and even universal, and offering answers on a single level only” (p.81).  What they point to is not simply the “philosophical tradition of reductionism,” but also “the institutional fragmentation of research, and the political economy of knowledge as a commodity” (p.9).  Indeed, their critical position extends beyond science to rejection of “the greed and brutality and smugness of late capitalism” (p.373).

Their anti-capitalist stance notwithstanding, the foci or starting points of L&L’s essays, like their 1986 collection, The Dialectical Biologist, lies in research in the life sciences.  Regarding the green revolution, for example, L&L see:

 …that a view based on unidirectional causation leads to the expectation that since grasses need nitrogen, a genotype that takes up more nitrogen would be more productive; since pesticides kill pests, their widespread use would protect crops; and since people eat food, increased yields would alleviate hunger (p.84).

The actual outcomes did not end up matching such simple causation because:

 …the increase in wheat yield was partly achieved by breeding for dwarf plants that are more vulnerable to weeds and to flooding; the killing of pests was accompanied by the killing of their natural enemies, their replacement by other pests, and the evolution of pesticide resistance.  The successful yield increases encouraged the diversion of land from legumes.  The technical packages of fertilizers, pesticides, irrigation, and mechanization promoted class differentiation in the countryside and displacement of peasants (p.84).

“A Program for Biology” ends with three fundamental questions for the study of complexity:

Why are things the way they are instead of a little bit different (the question of homeostasis, self-regulation, and stability)?  Why are things the way they are instead of very different (the question of evolution, history, and development)?  And what is the relevance to the rest of the world? (p.86)

The third question, rephrased in a later essay as “how [do we] intervene in these complex processes to make things better for us”? (p.115), invites… readers to ask what L&L’s essays tell us about having an effect—direct or indirect—on the complex processes of the production and application of scientific knowledge.  The essay review approaches this third question as it relates to social studies of science and technology and L&L’s contributions from four angles:

  • a more vigorous culture of science criticism;
  • a visible college of Marxist scientists in the USA;
  • inquiries into the diverse social influences shaping science; and
  • motivating readers who want to pursue their science as a political project.

Indirect contributions—influences on and appropriations by other actors in the wider realm of biology as politics—are discussed as well as the more direct effects.

Gender, Race, and the Complexities of Science and Technology: A bibliography

In a 2011 graduate course on “Gender, Race, and the Complexities of Science and Technology,” students were asked to add an annotated reference or resource (=person, organization…) to the evolving googledocs bibliography each week.  (Annotations were to convey the article’s key points as well as its connection to the student’s own inquiries and interests.)  The result is as follows: Read more of this post

The challenge of integrating ecological dynamics into evolutionary theory VIII: Darwin, the preempter of criticisms

When Darwin, in the third chapter of On the Origin of Species, explored evolution’s ecological context he was not simply laying out a program of research for a future science now called ecology (see previous post).  He was responding to anticipated criticisms of his theory of natural selection as the mechanism for evolutionary change that produces the “that perfection of structure and co-adaptation which most justly excites our admiration.”

Recall Darwin’s initial statement of the idea of natural selection.  Given the struggle for existence, “any variation, however slight and from whatever cause proceeding, if it is in any degree profitable to an individual of any species in its infinitely complex relations to other organic beings and to external nature, will tend to the preservation of that individual, and will generally be inherited by its offspring” (Darwin 1859, p.61).  He goes on, however, to note: “What checks the natural tendency of each species to increase in number is most obscure” (p. 67).  And at the end of the chapter, he concludes:  “It is good thus to try in our imagination to give any form some advantage over another. Probably in no single instance should we know what to do, so as to succeed. It will convince us of our ignorance on the mutual relations of all organic beings; a conviction as necessary, as it seems to be difficult to acquire” (p. 78).

In short, chapter 3 is a preemptive defence.  It was as if he were saying: “There must be such characters, but don’t ask me to show you what they are, to  identify what characters of an organism confer fit-ness.  There are too many indirect interactions and feedbacks to do this reliably.  Instead, we have to just take it as self-evident that there must be such characteristics.”  Having pointed to the complexity of ecological dynamics, the challenge remains, 150 years later, of integrating those dynamics into evolutionary theory.

Perhaps researchers will be able to show more cases in nature (as against in the lab.) in which organisms enjoy differential survival and reproductive success because of the effect of some character they possess.  But, given the special conditions (see earlier post) that increase the chances of natural selection (carefully construed) serving as an explanation of historical change—and conversely, the complexity of evolution’s ecological context—it may well be that finding many cases will be beyond the data and methodologies available.  The issues is not the existence of natural selection in the short term, say, for a generation; I am not positing chance and genetic drift instead of natural selection. The question is whether the generation-by-generation natural selection adds up over time to an outcome that we can, retrospectively, assign to natural selection associated with some specific character that increased in frequency in the population.

If this is a kind of methodological uncertainty principle that evolutionary biologists have to face, I wonder if there is also an ontologically uncertainty principle that organisms face.  Each organism makes its living in an ecological context.  Some leave more offspring than others.  But there are too many indirect interactions and feedbacks for an organism to make its living in ways that humans might call strategic with respect to perpetuating its lineage.  For all this, however, organic evolution on earth has taken place in complex ecological contexts for more than 4 billion years.

The challenge of integrating ecological dynamics into evolutionary theory VI: Five approaches

Integrating the structure and dynamics of evolution’s ecological context (see previous posts) remains a neglected project within evolutionary theory.  Nevertheless, the different approaches to theorizing ecological organization can still be read in terms of the ways that evolutionary theory fits into them, whether or not this is made explicit.  Table 1 provides a classification of five basic orientations.

Central to the first three orientations is the notion of system, which I use in the strong sense of an entity that has clearly defined boundaries and has coherent internal dynamics, dynamics that govern the system’s responses to external influences and determine its structure, stability and development over time (Taylor 1992). System in this sense can refer not only to the basic units of systems ecology, but also to the guilds and communities of community ecology.  These three orientations differ according to the relative time scales of ecological and evolutionary processes.  In contrast to viewing ecological organization as system-like, various ecologists have emphasized what I call its “unruly complexity” (Taylor 2005).  That is, organisms and processes transgress the boundaries of any unit of ecological structure, spanning levels and scales; natural categories for and reduction of the complexity are elusive; ecological structures are subject to restructuring; control and generalization are difficult.  The two non-system orientations differ according to whether this unruly complexity can be disciplined theoretically.   Table 1’s distinctions are illustrated in Taylor (2000) through a review of twentieth century theories of ecological organization.

In the next post in the series, I note Darwin’s keen awareness of the structure and dynamics of evolution’s ecological context and mention some research that follows in that tradition.

Table 1. Five orientations to theorizing ecological organization and evolution.

Focus Orientation Time scales
system (or community) system evolves as a Coherent whole Fast return to equilibrium; slow change or evolution of system
individuals in context of system Stable system Fast return to equilibrium

intermediate speed evolution of population of individuals

slow change of system

system transient, yet Regularly reoccurring Fast passing of transient context (e.g.,succession)

intermediate speed evolution of population of individuals

slow change in nature of transient context

ecological organization as not system-like Anti-Theory Relevant processes not separable into “ecological” and “evolutionary” time scales
unruly complexity can be Disciplined

Taylor, P. J. “Community” pp. 52-60 in E.F. Keller & E. Lloyd (eds.) Keywords in Evolutionary Biology, Harvard University Press, 1992
—- “From natural selection to natural construction to disciplining unruly complexity: The challenge of integrating ecology into evolutionary theory,” in R. Singh, K. Krimbas, D. Paul & J. Beatty (eds.), Thinking About Evolution: Historical, Philosophical and Political Perspectives, Cambridge: Cambridge University Press, 377-393, 2000.
—- Unruly Complexity: Ecology, Interpretation, Engagement Chicago: University of Chicago Press, 2005.

The challenge of integrating ecological dynamics into evolutionary theory V, developmental & ecological flexibility in the evolutionary origin of characters

An example of the contribution of developmental and ecological flexibility to the evolutionary origin of characters (see previous post) involves barn owls recently migrated to Malaysian oil palm plantations. Lenton (1983) describes the owls fifteen years after the first pair bred in a Malaysian plantation, by which time they had spread throughout southern Malaysia. The owls have two to three clutches a year, do not rigidly defend their territories, and perch to wait for their prey-the rats abundant in the plantations. In contrast, owls of the same species in Europe have only one clutch per year, rigidly defend their territories, frequent open areas, and quarter those areas in search of prey. Moreover, the juveniles in the Malaysian plantations, before the age of establishing their own nesting sites, congregate at the end of the day’s hunting-social behavior not observed elsewhere.

Now, if Darwinian biologists first observed the character differences between the Malaysian owls and their relatives without knowing about the recent immigration, my guess is that they might explain the increased fecundity and contracted territories as selectively advantageous in the environment of abundant rats. They would assume that there must have been some variation in fecundity and territory size in the original owls. The juvenile congregation would probably be passed over as simply a by-product of the other selected changes.

Suppose we then informed the biologists of how few generations there had been to accumulate any differentials that could have emerged from the offspring of the one founding pair. They would probably shift the focus of their explanation and postulate that barn owls have the flexibility to develop responses to novel environmental circumstances in appropriate ways, even if we have not observed the responses elsewhere.  Flexibility would be seen as an adaptation resulting from previous selection.  But I doubt that modern Darwinian biologists would go further and conclude that the owls have in fact evolved and adapted without any significant genetic change in the population.

Even if the biologists did not modify their definition of evolution to incorporate non-genetic change, the case indicates how the historical conjunction of circumstances and the previously unobserved ecological flexibility of the pre-immigrant owls elicited the new characters. This conjunction becomes crucial to the explanation of the changes that were observed in the population of oil palm owls—as important as, perhaps more important than, the genetics of character variation or any differential representation among variants after migration into Malaysia. Understanding evolutionary change does not license our focusing on the characters of individuals and not attending to the dynamic relationship between individual and contextual change.

Development is central to this story. Instead of single characters directly linked to genes, typically hypothetical, that arise through mutations or random rearrangement of DNA, we see that new characters arise within integrated sets of characters that develop over the organism’s lifetime. Instead of inheritance as the transmission from parent to offspring of Master Molecules, we have a picture of characters always being reproduced (imperfectly) through flexible developmental processes, processes that are only conditioned, not determined, by genes.

In the next post in the series I return to the original question of what it might look like to make evolutionary studies more ecological.


Lenton, G. (1983) “Wise owls flourish among the oil palms,” New Scientist, 97: 436-437

An extract from Taylor, P. (1998) “Natural Selection: A heavy hand in biological and social thought,” Science as Culture, 7 (1), 5-32.


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