Tag Archives: natural history

Zambia paleo dig yields new insights on Permian-Triassic environments

Mark Alvey


Please note: this news story, recovered on 28-Jan-2017, was originally published in Science Dialogues on 27-August-2014.


Ken Angielczyk in the Luangwa Basin of Zambia holding two specimens of the dicynodont Diictodon. Photo by Roger Smith.

Associate Curator Ken Angielczyk of The Field Museum was part of an international team of collaborators that conducted paleontological fieldwork in Zambia between June 22 and July 31. Ken and his collaborators focused on Middle Permian (~265 Mya) to Middle Triassic (~240 Mya) rocks in two areas of the country, the Zambezi Basin in southern Zambia and the Luangwa Basin in northeastern Zambia. The team had done preliminary work in the Zambezi Basin in 2011 and 2012, but only spent a total of about 5 days working there. This time, they spent about two weeks there and their discoveries include multiple species of archaic amphibians and dinocephalians and dicynodonts (both ancient mammal relatives) from the Middle Permian, extremely well preserved fossil wood, and evidence that two temporally-distinct faunas are preserved in the Permian rocks in the Zambezi Basin. They also collected a large amount of geological data that will help complete the picture of the environments in which the plants and animals were living.

Ken’s colleagues Sebastien Steyer and Charles Beightol excavate a dinocephalian skeleton preserved in Permian rocks in the Zambezi Basin of Zambia. Photo: Cristian Sidor.

The team had conducted more extensive fieldwork in the Luangwa Basin in 2009 and 2011, and this year their work focused on rounding out their previous collections and collecting more geological data to understand  paleoenvironments. Among their discoveries is evidence of strong associations of particular dicynodonts with specific environments in the Late Permian rocks of the Luangwa Basin, and strong evidence of increased aridity and changes in the nature of river systems in the area moving from the Late Permian to the Middle Triassic. Ken and his collaborators will use these data to investigate the role environmental changes played in shaping the end-Permian mass extinction (the largest extinction in Earth history) and the recovery following the event.

Ulemosaurus svijagensis – primitive tapinocephalian from Middle Permian of Tatarstan. Illustration by Dmitry Bogdanov. Source: https://en.wikipedia.org/wiki/Ulemosaurus#/media/File:Ulemosaurus22DB.jpg.

And one important result of fieldwork like that: scientific publications.  Ken and colleagues have a paper in the July issue of Journal of Vertebrate Paleontology describing fossils of tapinocephalids from Southern Zambia.  Tapinocephalids are hippo-sized, herbivorous mammal relatives that lived about 265 million years ago; the fossils were discovered by Ken and his collaborators during short exploratory trips to the Zambezi Basin in southern Zambia in 2011 and 2012. They are the oldest known tetrapod remains from Zambia, and demonstrated the potential of the area for further paleontological exploration (as in previous item). This is also the second time that Ken and his teammates have discovered tapinocephalids in an area from which they were previously unknown (the first time was in 2008 in Tanzania).

© 2014 Mark Alvey. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES

Reconfiguring biological diversity 2. Coming to grips with diversity

John Edward Terrell


This is part 2 of a two part article

Coming to grips with diversity

Perhaps the greatest stumbling block to deciphering how biological diversity is patterned, or structured, in space and time within any given species is that most existing ways of modeling such diversity presuppose that genes are nested in some fashion within demonstrable and persistent primary units that can be labeled as populations, subpopulations, demes, communities, stocks, races, and like. Yet is this how biological reproduction works? Aren’t genes perfectly capable of “escaping,” so to speak, from such allegedly defining and confining “boxes” through the very acts of reproduction, reassortment, growth, and development?

It could be argued that there is irony in the fact that molecular genetics now has made it possible for scientists to map diversity at the genetic level. Yet many are still given to thinking about diversity as if they were compelled by the old limitations of their laboratory techniques to lump this new fine-grained evidence into inclusive nested sets (e.g., Pritchard et al. 2000; Greenbaum et al. 2016; Skoglund et al. 2016).

Perhaps it is not surprising, therefore, that some have concluded that “the observed pattern of global gene identity variation was produced by a combination of serial population fissions, bottlenecks and long-range migrations associated with the peopling of major geographic regions, and subsequent gene flow between local populations” (Hunley et al. 2009).

All three of these identified processes are plausible reasons for biological diversity in time and space. But aren’t all three of these population-level explanations ignoring individual agency and decision-making? Not to mention love, lust, and human compassion?

Moving beyond population modeling

Current population-level modeling based on molecular genetics is arguably an advance over older metapopulation models framing diversity as an ever-changing flux within species among discrete subpopulations inhabiting separate habitat patches linked by migration and extinction (Fig. 2). Certainly few today would accept that diversity within any species can be adequately explained solely or even largely as the product of fluctuating colonization and extinction events.

Figure 2. A simple metapopulation model at two time periods (A and B) attributing spatial diversity to a shifting dynamic of colonization and extinction events.

Similarly, the concept of the fitness landscape (also known as as an adaptive landscape; see Fig. 3) introduced by the geneticist Sewell Wright in 1932 is another long-debated way of modeling the dynamic interplay—or balance—of a number of plausible determinants of genetic variation in space and time. As Wright explained in 1932:

The most general conclusion is that evolution depends on a certain balance among its factors. There must be gene mutation, but an excessive rate gives an array of freaks, not evolution; there must be selection, but too severe a process destroys the field of variability, and thus the basis for further advance; prevalence of local inbreeding within a species has extremely important evolutionary consequences, but too close inbreeding leads merely to extinction. A certain amount of crossbreeding is favorable but not too much. In this dependence on balance the species is like a living organism. At all levels of organization life depends on the maintenance of a certain balance among its factors. (Wright 1932)

Figure 3. “Field of gene combinations occupied by a population within the general field
of possible combinations. Type of history under specified conditions indicated by relation
to initial field (heavy broken contour) and arrow.” Source: Wright 1932, fig. 4.

A “balance of factors” sounds right and reasonable, but are the ones he mentions the only major factors that must be taken into account? Surely adaptation is not the only driving force of evolution?

Agency and social networks

Consider the observation that human beings are notably variable in stature, weight, and other characteristics of their appearance. Clearly the gene mutations supporting such phenotypic variation have not resulted in what Wright would describe as “an array of freaks.” Evidently such diversity is not selected against—to use Wright’s way of framing the discussion. Why? Because much of the burden of human adaptation does not need to be genetically endowed. Instead, as most social scientists would insist, much of what we do supporting our survival and reproduction is accomplished using socially learned skills rather than by genetically inherited biological means.

Recently Greenbaum and his colleagues observed that the research strategies and tools of modern network analysis are increasingly being used to explore genetics questions in genomics, landscape genetics, migration-selection dynamics, and the study of the genetic structure of species more generally speaking (Greenbaum et al. 2016).

Adopting a networks approach to genetics makes it possible to come to grips not only with the ways in which racism—to return to Roseman’s point raised earlier—has shaped human variation in the past few hundred years, but also how our species’ mobility, adaptive skills, technologies, and social behaviors have been configuring human variation throughout the history of our species.

Figures 4 and 5 illustrate the potential value of using of network analysis in the study of genetic diversity. The first figure is a network mapping of localities reported in a genome scan published in 2008. While the patterning is complex, there is an obvious geographic signal in the genetic linkages shown. Figure 5 resolves the relationships among a smaller subset of the localities that had been sampled, specifically those in the Bismarck Archipelago-North Solomons region of the southwest Pacific.

Figure 4. Spring-embedding network mapping of the localities sampled in a genome scan of autosomal markers (687 microsatellites and 203 insertions/deletions) on 952 individuals from 41 Pacific populations). Mapping derived from the mean STRUCTURE assignment probabilities when K = 10 reported by Friedlaender at al. (2008) color-coded by geographic location. Blue-white = Asia; blue = Taiwan; black = Europe; red = Polynesia; pink = Micronesia; yellow = New Britain; purple = New Guinea; dark green = North Solomons; green = New Ireland; light green = New Hanover; pale green = Mussau. Source: adapted from Terrell 2010b, fig. 3.

 

Figure 5. Nearest-neighbor structuring of interaction among the localities sampled in the Bismarck Archipelago and North Solomons color-coded to show genetic clustering (blue nodes represent locations not represented in the genetic scan). Source: Terrell 2010b, fig. 11.Both network mappings suggest that geography has influenced the structuring of genetic similarities among people living in the sampled localities shown. Yet it also is apparent that the linkages shown may often be closer than geographic distance alone would lead us to expect. Judging by figure 5, the effect of isolation by distance is evidently constrained by social networks (as projected in this figure using nearest-neighbor linkages). Hence while geographic distance may be contributing to the patterning of genetic diversity among people in this part of the world, geography is by no means the whole story.
Conclusions

The network analysis briefly introduced in figures 4 and 5 had two principal aims, one phylogenetic, the other tokogenetic (Terrell 2010b). Do people living today in the Pacific segregate genetically along lines concordant with the reputedly separate (i.e., cladistic) histories of languages spoken there, principally the divide drawn by linguists and others between speakers of Austronesian and non-Austronesian (Papuan) languages (Terrell 2006)? To what extent does the genetic similarity among people living in different residential communities correlate with the nearest-neighbor propinquity of these sampled places?

Neither of these aims presuppose that the research goal is to define genetically discrete human populations (or subpopulations, demes, groups, communities, races, and the like) either a priori or by using, say, individual-based clustering (IBC) methods (e.g., Ball et al. 2010).

These two aims have more in common with those of the emerging field of landscape genetics (Dyer and Nason 2004; Garroway et al. 2008) than with most previous research in population genetics. However, both of these aims focus more directly on the genetic consequences of the behavior of organisms in space and time—in this case, humans—than on the geography, ecology, and environmental history of the locales where the people in question reside.

Both can also be seen as stepping back from Roseman’s observations about the impact of racial politics and social practices on the human genome in the past few centuries to underscore a more general issue in evolutionary biology: How much do the mobility and social behavior of individuals within any given animal species structure the genetic variation of that species?

As Dyer and Nason (2004) have remarked: “The evolution of population genetic structure is a dynamic process influenced by both historical and recurrent evolutionary processes.” Using network theory and visualization techniques to map the genetic structure of a species in space and time is still in its infancy. Reconfiguring how science grapples with the inherent complexity of evolution as an ever unfolding process using network approaches has the promise of making it easier to explore how comparable or dissimilar species are in their strategies for survival and reproduction (Fortuna et al. 2009).

Looking long and hard at what other species do to survive and reproduce may make it easier for us to see just how toxic our own social strategies—and the assumptions supporting them—can be.

Acknowledgements

I thank Neal Matherne and Tom Clark for their comments on a draft of this commentary.

References

Ball, Mark C., Laura Finnegan, Micheline Manseau, and Paul Wilson. 2010. Integrating multiple analytical approaches to spatially delineate and characterize genetic population structure: An application to boreal caribou (Rangifer tarandus caribou) in central Canada. Conservation Genetics 11, 6: 2131-2143.

Dyer, Rodney J., and John D. Nason. 2004. Population graphs: The graph theoretic shape of genetic structure. Molecular ecology 13, 7: 1713-1727.

Fortuna, Miguel A., Rafael G. Albaladejo, Laura Fernández, Abelardo Aparicio, and Jordi Bascompte. 2009. Networks of spatial genetic variation across species. Proceedings of the National Academy of Sciences 106, 45: 19044-19049.

Friedlaender, Jonathan S., Françoise R. Friedlaender, Jason A. Hodgson, Matthew Stoltz, George Koki, Gisele Horvat, Sergey Zhadanov, Theodore G. Schurr, and D. Andrew Merriwether. 2007. Melanesian mtDNA complexityPLoS One 2, 2: e248.

Friedlaender, Jonathan S., Françoise R. Friedlaender, Floyd A. Reed, Kenneth K. Kidd, Judith R. Kidd, Geoffrey K. Chambers, Rodney A. Lea et al. 2008. The genetic structure of Pacific IslandersPLoS Genet 4, 1: e19.

Garroway, Colin J., Jeff Bowman, Denis Carr, and Paul J. Wilson. 2008. Applications of graph theory to landscape genetics. Evolutionary Applications 1, 4: 620-630.

Greenbaum, Gili, Alan R. Templeton, and Shirli Bar-David. 2016. Inference and analysis of population structure using genetic data and network theory. Genetics 202.4: 1299-1312.

Hellenthal, Garrett, George BJ Busby, Gavin Band, James F. Wilson, Cristian Capelli, Daniel Falush, and Simon Myers. 2014. A genetic atlas of human admixture history.” Science 343, 6172: 747-751.

Hunley, Keith, Michael Dunn, Eva Lindström, Ger Reesink, Angela Terrill, Meghan E. Healy, George Koki, Françoise R. Friedlaender, and Jonathan S. Friedlaender. 2008. Genetic and linguistic coevolution in Northern Island MelanesiaPLoS Genet 4, no. 10 (2008): e1000239.

Hunley, Keith L., Meghan E. Healy, and Jeffrey C. Long. 2009. The global pattern of gene identity variation reveals a history of long‐range migrations, bottlenecks, and local mate exchange: Implications for biological race. American Journal of Physical Anthropology 139, 1: 35-46.

Kelly, Kevin M.,  2002. Population. In Hart, J. P. & Terrell, J. E. (eds.) Darwin and Archaeology: A handbook of key concepts, pp 243–256. Westport, Ct: Bergin & Garvey.

Moore, John H. 1994. Putting anthropology back together again: The ethnogenetic critique of cladistic theory. American Anthropologist (1994): 925-948.

Posada, David, and Keith A. Crandall. 2001. Intraspecific gene genealogies: Trees grafting into networks. Trends in Ecology & Evolution 16, 1: 37-45.

Pritchard, Jonathan K., Matthew Stephens, and Peter Donnelly. 2000. Inference of population structure using multilocus genotype data. Genetics 155, 2: 945-959.

Rieppel, Olivier. 2009. Hennig’s enkaptic system. Cladistics 25, 3: 311-317.

Roseman, Chartes C. 2014. Troublesome Reflection: Racism as the Blind Spot in the Scientific Critique of Race” Human biology 86, 3: 233-240.

Roseman, Charles C. 2014. “Random genetic drift, natural selection, and noise in human cranial evolution. Human Biology 86, 3: 233-240.

Skoglund, Pontus, Cosimo Posth, Kendra Sirak, Matthew Spriggs, Frederique Valentin, Stuart Bedford, Geoffrey R. Clark et al. 2016. Genomic insights into the peopling of the Southwest Pacific. Nature 538: 510-513.

Terrell, John Edward. 2006. Human biogeography: Evidence of our place in nature. Journal of Biogeography 33, 12: 2088-2098.

Terrell, John Edward. 2010a. Language and material culture on the Sepik coast of Papua New Guinea: Using social network analysis to simulate, graph, identify, and analyze social and cultural boundaries between communities. Journal of Island & Coastal Archaeology 5, 1: 3-32.

Terrell, John Edward. 2010b. Social network analysis of the genetic structure of Pacific islanders. Annals of human genetics 74, 3: 211-232.

Terrell, John Edward. 2015. A Talent for Friendship: Rediscovery of a Remarkable Trait. Oxford University Press.

Terrell, John Edward, and Pamela J. Stewart. 1996. The paradox of human population genetics at the end of the twentieth century. Reviews in Anthropology 25, 1: 13-33.

Wade, Nicholas. 2014. A Troublesome Inheritance: Genes, Race and Human History. Penguin.

Wilson, David Sloan, and Edward O. Wilson. 2008. Evolution for the Good of the Group”: The process known as group selection was once accepted unthinkingly, then was widely discredited; it’s time for a more discriminating assessment. American Scientist 96, 5: 380-389.

Wright, Sewall. 1932. The roles of mutation, inbreeding, crossbreeding, and selection in evolution. Proceedings of the Sixth International Congress of Genetics , Vol. 1: 356-366.

© 2017 John Edward Terrell. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Reconfiguring biological diversity 1. Toxic and obsolete assumptions

John Edward Terrell


This is part 1 of a two part article

IN AN INSIGHTFUL REVIEW of Nicholas Wade’s recent book A Troublesome Inheritance: Genes, Race and Human History (Wade 2014), the anthropological geneticist Charles C. Roseman concluded that current scientific arguments against biological racism are weak and scattered. These failings—my word, not Roseman’s—are far more than just scientifically troubling. “To recuperate a useful scientific critique of race,” he argues, “we need to come to grips with ways in which the political processes of racism have shaped human organisms over the last few hundred years” (Roseman 2014).

As Roseman notes, nobody seriously contests that human variation “is structured in geographic space, through time, and across many social divisions.” What is still up for grabs is how to explain this observable diversity. And as Roseman emphasizes, how we explain human variation cannot ignore the divisive and often destructive power of racism as a potent driver of human evolution. “Without incorporating the effects of racism into models of human variation today, we will not be able to have a cohesive theory of genes and race, and the scientific critique of race will continue to have no teeth.”

While Roseman’s observations focus on human biological diversity, the weaknesses and uncertainties he has highlighted about our explanations for variation within our species apply also to modern science’s grasp of biological diversity more broadly speaking. From this more inclusive point of view, racism is just a particularly invidious human form of social behavior capable of patterning our genetic diversity in time and space. If so, what about other species? How does the patterning of their mobility and social behavior shape their genetic diversity?

“Populations,” “admixture,” and conventional wisdom

Although the human brain can be coaxed into paying close attention to detail and nuance,  as a thinking machine it generally favors expediency and the utility of knowledge over precision and accuracy.  It is not altogether surprising, therefore, that even scientists often still take it for granted that biological species are naturally subdivided into separate “populations” or “subspecies” that  may occasionally—say under changing demographic or environmental conditions—meet and mix, and thereby produce more or less isolated “admixed” new hybrids (e.g., Moore 1994; Hellenthal et al. 2014). The question being overlooked or at any rate downplayed is how real and persistent are these assumed “populations” (Terrell and Stewart 1996; Kelly 2002).

This question may sound academic, but it is not trivial, as Charles Roseman has underscored. When it comes to human beings, the favored word in scholarly circles may be the word population or perhaps deme, group, or community, but for the chap on the street, the more likely choice wouldn’t be one of these formal terms, but rather the more down-to-earth word race. (I still vividly remember being scolded by a famous biological anthropologist decades ago when I was an undergraduate for using this particular “r” word. “We don’t use that word anymore,” he told me. “We use the term stock  instead.”)

What’s at stake here

It has been a foregone assumption in most genetics research for years that different species are by definition and by their biology isolated reproductively from one another, i.e., individuals in different species cannot mate and give birth to viable offspring capable of sustaining life for longer than a single generation. However, even the most committed cladist accepts that biological relationships below the level of the species are tokogenetic, not phylogenetic (Posada and Crandall 2001; Rieppel 2009).

Figure 1. “Tokogeny versus phylogeny. (a) Processes occurring among sexual species (phylogenetic processes) are hierarchical. That is, an ancestral species gives rise to two descendant species. (b) Processes occurring within sexual species (tokogenetic processes) are nonhierarchical. That is, two parentals combine their genes to give rise to the offspring. (c) The split of two species defines a phylogenetic relationship among species (thick lines) but, at the same time, relationships among individuals within the ancestral species (species 1) and within the descendant species (species 2 and 3) are tokogenetic (arrows).” Source: Posada and Crandall 2001, fig. 1.

Here, therefore, is the conundrum. Call them what you want, populations within any given species are not inherently isolated reproductively either by definition and by their biology. Hence to treat populations as natural units, they must first be defined and demonstrated to be isolated and discernible as such in some other way, or ways. Can this be done?

Here is one favored way when the species in question is ourselves. Many people believe that the language you speak is a reliable sign or marker of your true ethnicity and even your race. Is this right?

Hardly. As both fable and risqué jokes alike would have it, any sailor arriving in a strange port of call is likely to discover soon enough that you don’t really need to speak the local language to enjoy a good time while ashore as long as you have a few coins in your pocket. Yet scholars have long written about people living in what some see as the “underdeveloped” regions of the world as being subdivided into recognizable ethnolinguistic groups, language communities, and the like despite the fact that such euphemisms for the old-fashioned word race pigeonhole rather than map the realities of their lives (Terrell 2010a).

But if neither biology nor language inherently—i.e., “naturally”—isolates and thereby subdivides human beings as a species into different populations, subpopulations, demes, communities, stocks, or races, is there anything that does? And what about other species on earth?

Competition and tribalism, or isolation-by-distance?

As Roseman has remarked: “All analyses of human variation make strong assumptions about the mode, tempo, and pattern whenever they interpret statistical results to make evolutionary conclusions” (Roseman 2016). Favored explanations for or against the assumption that our species can be subdivided into enduring natural populations largely fall into one or the other of two basic sorts.

On the one hand, there has long been anecdotal and scholarly evidence, too, that geography and topography can limit how well and how often people are able to stay in touch with one another socially and intellectually as well as sexually. As the authors of one recent study commented, research has shown that there is a strong positive correlation between global genetic diversity within our species and geographic distance. The correlations observed have often been interpreted “as being consistent with a model of isolation by distance in which there are no major geographic discontinuities in the pattern of neutral genetic variation” (Hunley et al. 2009).

As these same authors note, however, discordant gene frequency patterns are also common within our species. It is obvious, too, that physical and social impediments to gene flow have regularly produced both larger discontinuities as well as concordant allele frequency patterns than would be expected based solely on isolation-by-distance (clinal) models of variation (Ibid.).

Adding social impediments to the mix of possible explanations brings into play the second way many have tried to explain why people around the globe appear to be so diverse. While there are many variants of this alternative argument, the essential ingredients are the baseline assumptions that (a) competition between individuals and groups is the main driving force of evolution, (b) human beings are by nature selfish and aggressive creatures, and (c) until recently humans lived in small tribal groups that were not just suspicious of strangers and other communities near and far, but were frequently at war them them, too. All of these claims are not only questionable, but are arguably contrary to the fundamental evolved characteristics of our species (Terrell 2015).


Part 2: Coming to grips with diversity 


References

Ball, Mark C., Laura Finnegan, Micheline Manseau, and Paul Wilson. 2010. Integrating multiple analytical approaches to spatially delineate and characterize genetic population structure: An application to boreal caribou (Rangifer tarandus caribou) in central Canada. Conservation Genetics 11, 6: 2131-2143.

Dyer, Rodney J., and John D. Nason. 2004. Population graphs: The graph theoretic shape of genetic structure. Molecular ecology 13, 7: 1713-1727.

Fortuna, Miguel A., Rafael G. Albaladejo, Laura Fernández, Abelardo Aparicio, and Jordi Bascompte. 2009. Networks of spatial genetic variation across species. Proceedings of the National Academy of Sciences 106, 45: 19044-19049.

Friedlaender, Jonathan S., Françoise R. Friedlaender, Jason A. Hodgson, Matthew Stoltz, George Koki, Gisele Horvat, Sergey Zhadanov, Theodore G. Schurr, and D. Andrew Merriwether. 2007. Melanesian mtDNA complexityPLoS One 2, 2: e248.

Friedlaender, Jonathan S., Françoise R. Friedlaender, Floyd A. Reed, Kenneth K. Kidd, Judith R. Kidd, Geoffrey K. Chambers, Rodney A. Lea et al. 2008. The genetic structure of Pacific IslandersPLoS Genet 4, 1: e19.

Garroway, Colin J., Jeff Bowman, Denis Carr, and Paul J. Wilson. 2008. Applications of graph theory to landscape genetics. Evolutionary Applications 1, 4: 620-630.

Greenbaum, Gili, Alan R. Templeton, and Shirli Bar-David. 2016. Inference and analysis of population structure using genetic data and network theory. Genetics 202.4: 1299-1312.

Hellenthal, Garrett, George BJ Busby, Gavin Band, James F. Wilson, Cristian Capelli, Daniel Falush, and Simon Myers. 2014. A genetic atlas of human admixture history.” Science 343, 6172: 747-751.

Hunley, Keith, Michael Dunn, Eva Lindström, Ger Reesink, Angela Terrill, Meghan E. Healy, George Koki, Françoise R. Friedlaender, and Jonathan S. Friedlaender. 2008. Genetic and linguistic coevolution in Northern Island MelanesiaPLoS Genet 4, no. 10 (2008): e1000239.

Hunley, Keith L., Meghan E. Healy, and Jeffrey C. Long. 2009. The global pattern of gene identity variation reveals a history of long‐range migrations, bottlenecks, and local mate exchange: Implications for biological race. American Journal of Physical Anthropology 139, 1: 35-46.

Kelly, Kevin M.,  2002. Population. In Hart, J. P. & Terrell, J. E. (eds.) Darwin and Archaeology: A handbook of key concepts, pp 243–256. Westport, Ct: Bergin & Garvey.

Moore, John H. 1994. Putting anthropology back together again: The ethnogenetic critique of cladistic theory. American Anthropologist (1994): 925-948.

Posada, David, and Keith A. Crandall. 2001. Intraspecific gene genealogies: Trees grafting into networks. Trends in Ecology & Evolution 16, 1: 37-45.

Pritchard, Jonathan K., Matthew Stephens, and Peter Donnelly. 2000. Inference of population structure using multilocus genotype data. Genetics 155, 2: 945-959.

Rieppel, Olivier. 2009. Hennig’s enkaptic system. Cladistics 25, 3: 311-317.

Roseman, Chartes C. 2014. Troublesome Reflection: Racism as the Blind Spot in the Scientific Critique of Race” Human biology 86, 3: 233-240.

Roseman, Charles C. 2014. “Random genetic drift, natural selection, and noise in human cranial evolution. Human Biology 86, 3: 233-240.

Skoglund, Pontus, Cosimo Posth, Kendra Sirak, Matthew Spriggs, Frederique Valentin, Stuart Bedford, Geoffrey R. Clark et al. 2016. Genomic insights into the peopling of the Southwest Pacific. Nature 538: 510-513.

Terrell, John Edward. 2006. Human biogeography: Evidence of our place in nature. Journal of Biogeography 33, 12: 2088-2098.

Terrell, John Edward. 2010a. Language and material culture on the Sepik coast of Papua New Guinea: Using social network analysis to simulate, graph, identify, and analyze social and cultural boundaries between communities. Journal of Island & Coastal Archaeology 5, 1: 3-32.

Terrell, John Edward. 2010b. Social network analysis of the genetic structure of Pacific islanders. Annals of human genetics 74, 3: 211-232.

Terrell, John Edward. 2015. A Talent for Friendship: Rediscovery of a Remarkable Trait. Oxford University Press.

Terrell, John Edward, and Pamela J. Stewart. 1996. The paradox of human population genetics at the end of the twentieth century. Reviews in Anthropology 25, 1: 13-33.

Wade, Nicholas. 2014. A Troublesome Inheritance: Genes, Race and Human History. Penguin.

Wilson, David Sloan, and Edward O. Wilson. 2008. Evolution for the Good of the Group”: The process known as group selection was once accepted unthinkingly, then was widely discredited; it’s time for a more discriminating assessment. American Scientist 96, 5: 380-389.

Wright, Sewall. 1932. The roles of mutation, inbreeding, crossbreeding, and selection in evolution. Proceedings of the Sixth International Congress of Genetics , Vol. 1: 356-366.

© 2017 John Edward Terrell. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

Darwin’s use of “use” and “disuse” (Part 3)

Tom Clark


Please note: this commentary, recovered on 8-Jan-2017, was originally published by the author, Tom Clark, on Science Dialogues on 14-Mar-2015.


DARWIN IS CREDITED with dethroning humans from their special place between animals and angels. As Copernicus had done astronomically, so had Darwin biologically.

Feral_horses_-_Pryor_Mountain_Wild_Horse_Range_-_Montana

Pryor Mountain Wild Horse Range, Montana. http://www.blm.gov/pgdata/etc/medialib/blm/mt/blm_programs/whb.Par.0228.Image.198.149.1.gif

But Darwin achieved continuity of humans with animals as much by humanizing animals as shrinking humans. Resisting “the too-ready ascription of action to instinct” (Beer 2009: 242-255), Darwin imagined that horses “admired a wide prospect,” baboons had “capacious hearts,” earthworms made aesthetic choices, and snails showed “some degree of permanent attachment.” He did not imagine that biology could benefit, as physics had, by abandoning animism, animals being so . . . animistic.

It was the neo-Darwinian assumption that genes and environments were sufficient causes of animals’ behavior that turned natural selection from an animate doing into a physical happening. Attributing behavior to stable causes both inside (molecules) and outside (environment) turned animals into spectators, along for the ride. Their mental lives were made redundant in the British sense of unemployed. (Compare John and Gabriel Terrell’s thoughts about self-generated, stimulus-independent, internally directed thought in their March 3 post Thinking about Thinking 2. Through the Looking Glass.)

Misreading Darwin’s use of use and disuse as simply Lamarckian enabled the neo-Darwinian demotion of both humans and animals, as meaningful roles for ancestors and Gods were, like baby and bathwater, summarily thrown out.

The word purpose is singularly inapplicable to evolutionary change … If an organism is well adapted … this is not due to any purpose of its ancestors or of an outside agency, such as “Nature” or “God” … (Mayr 1961: 1504).

The purposeful activities of ancestors were not final or ultimate causes. They were some among many causes. Yet they were bundled with God’s finality and dismissed. In the last paragraph of Origin of Species (Darwin 1860: 490) between his “entangled bank” metaphor and the poetic “endless forms most beautiful,” Darwin summarized the key elements of his theory. Two have been pushed to the edges of mainstream evolutionary thought, the ultimate activities of “the Creator” and the contingent activities of ancestors—”use and disuse.”

In the margins of an article by Wallace, Darwin wrote “use of moral qualities” (Greene 1981: 102), telegraphing a view of our moral origins that insinuated these dignifying lines of descent:

  • Life is inherently autonomous.
  • Autonomy has evolved (Rosslenbroich 2014).
  • Nervous systems support flexible, adaptive responding.
  • Vertebrates specialized in intention, allowing metabolic support for increasingly larger brains (Wrangham 2009).
  • Birds and mammals made relationships vital heritable resources (Kemp 2006), expanding autonomy by cooperating in relationships of secure dependence and interdependence.
  • Humans extended these achievements with ethics (Boehm 2012) and friendship (Terrell 2015).

The twentieth century dethroning of humanity carried out in Darwin’s name clipped human dignity more than Darwin intended. The following affirmations return to the evolutionary image of ourselves buds of autonomy and responsibility that Darwin was careful to leave on our family tree.

affirmWhen we consider the evolutionary role of animal behavior—or as we also say, ancestors’ activities—scientific theory becomes human nature mythology, the telling of which must be recognized as a moral act (Bock 1994: 8). The moral significance of our origin story hits home with the realization that how we tell this story can leverage or constrain personal and collective action toward sustainability (Clark and Clark 2012), peace and justice (Chorover 1979; Oyama 2000; Novoa and Levine 2010).

The sense we make of ourselves and each other shapes who we become, including our capacities for learning, cooperation and self-regulation. “Knowing” that intelligence is fixed inhibits learning (Blackwell et al. 2007). “Knowing” that personality attributes are inherited impels hasty negative judgments of others, foreclosing opportunities for constructive encounter (Dweck 2000). “Knowing” that free will is illusory engenders cheating (Vohs and Schooler 2008) and aggression (Baumeister et al. 2009). “Knowing” that humans are selfish by nature favors policies that crowd out reciprocity and trust, inducing selfish behavior (Bowles 2008). And “knowing” that metabolism is natural while intention remains a supernatural specter (Mayr 1982) hedges responsibility for our extended metabolism—energy consumption—compromising our ability to regulate our own inventions.

Knowing there is a choice to make and it matters what we choose to do prepares us for wising up to shared responsibilities and cooperating in the good use of resources.

Biologists rightly argue that a clear understanding of our evolutionary past must inform our plans for a sustainable future (Vermeij 2010: 253). Explaining the evolution of sighted animals as a blind process blinkers our understanding of the past, so also our outlook. Envisioning and motivating sustainable living is better served by an origin story that includes the vision and intentions of ancestors.

Evolution is not only what happened to our ancestors while they were busy making other plans. Ancestors did not plan our evolution, but their plans, successful or not, with consequences intended or not, were part of the story.

In the way he used use and disuse, Darwin recognized our ancestors’ part in how we came to be and our part in resolving where we go from here. By affirming our autonomy and interdependence, Darwin’s origin story also demands of us continued use of our moral imaginations.

References

Baumeister, R. F., E. J. Masicampo, and C. N. DeWall (2009). Prosocial benefits of feeling free: disbelief in free will increases aggression and reduces helpfulness. Personality and Social Psychology Bulletin 35: 260–268.

Beer, G. (2009). Darwin’s Plots (3rd ed.). Cambridge: Cambridge University Press.

Blackwell, L. S., K. H. Trzesniewski, and C. S. Dweck (2007). Implicit theories of intelligence predict achievement across an adolescent transition: a longitudinal study and an intervention. Child Development 78: 246–263.

Bock, K. (1994). Human Nature Mythology. Urbana: University of Illinois Press.

Boehm, C. (2012). Moral Origins. New York: Basic Books.

Bowles, S. (2008). Policies designed for self-interested citizens may undermine ‘the moral sentiments’: evidence from economic experiments. Science 320: 94–112.

Chorover, S. L. (1979). From Genesis to Genocide. Cambridge: MIT Press.

Clark, T. and E. Clark (2012). Participation in evolution and sustainability. Transactions of the Institute of British Geographers 37: 563–577.

Darwin, C. R. (1860). On the Origin of Species (2d ed.). In J. van Wyhe, ed., 2002 The Complete Work of Charles Darwin Online(http://darwin-online.org.uk).

Dweck, C. S. (2000). Self Theories. Philadelphia: Psychology Press.

Greene, J. C. (1981). Science, Ideology, and World View. Berkeley: University of California Press.

Kemp, T. S. (2006). The origin of mammalian endothermy: A paradigm for the evolution of complex biological structure. Zoological Journal of the Linnean Society 147: 473–488.

Mayr E. (1961). Cause and effect in biology. Science 134, 3489: 1501–1506.

Mayr E. (1982). The Growth of Biological Thought. Cambridge: Harvard University Press.

Novoa, A. and A. Levine (2010). From Man to Ape. Chicago: University of Chicago Press.

Oyama, S. (2000). Evolution’s Eye. Durham: Duke University Press.

Rosslenbroich, B. (2014). On the Origin of Autonomy. Cham: Springer.

Terrell, J. E. (2015). A Talent for Friendship. Oxford: Oxford University Press.

Vermeij G. J. (2010). The Evolutionary World. New York: St. Martin’s Press.

Vohs, K. D. and J. W. Schooler (2008). The value of believing in free will: encouraging a belief in determinism increases cheating. Psychological Science 19: 49–54.

Wrangham, R. (2009). Catching Fire. New York: Basic Books.

Tom Clark

As a psychologist, I have been interested in the role of behavior in evolution since my graduate training at the University of South Florida.

 

 

© 2015, Thomas L. Clark. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed in this article are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

 

 


Darwin’s use of “use” and “disuse” (Part 2)

Tom Clark


Please note: this commentary, recovered on 8-Jan-2017, was originally published by the author, Tom Clark, on Science Dialogues on 7-Mar-2015.


AT CHICAGO’S CENTENNIAL CELEBRATION of Origin of Species, Julian Huxley (1960: 14) attributed to Darwin this “Lamarckian error”:

… he did believe in the inheritance of certain “acquired characters”—the effects of the conditions of life and of use and disuse.

Though Darwin had been careful to use the terms use and disusedescriptively in Origin of Species, Huxley took them as categorically Lamarckian, a separate alternative to natural selection that did not mingle with it.

Ernst Mayr also presented Darwin’s thinking about use and disuse as singularly Lamarckian, in support of which he quoted from Origin of Species (1859: 134):

There can be little doubt that use in our domestic animals strengthens and enlarges certain parts and disuse diminishes them; and that such modifications are inherited.

Underscoring his Lamarckian take on Darwin, Mayr adds (1982: 691):

Use and disuse, of course, is of importance only if one believes in an inheritance of acquired characters. This Darwin affirms repeatedly … Darwin is quite positive: “Modifications [caused by use and disuse] are inherited.”

Standing alone, the sentence Mayr quotes from Origin of Species looks like a Lamarckian match. With each step back to see it in context, the resemblance fades.

In the next sentence, Darwin (1859: 134) refers to “… the effects of long-continued use and disuse,” not one generation to the next.

In the same paragraph he places use and disuse in the situation of stable selection pressures, offering as examples the “… wingless condition of several birds, which … inhabited several oceanic islands tenanted by no beasts of prey.”

On the next page he explicitly rejects Lamarckian inheritance of mutilations.

On the following page he clarifies “long-continued,” referring to “thousands of successive generations.”

And throughout Origin of Species, Darwin uses “acquired” only in reference to species across many generations in the context of specific selection pressures, not in the Lamarckian sense of individuals transmitting from one generation to the next characteristics acquired during their lifetimes.

In context, the “domestic animals” Darwin drew to our attention were domesticated species, not his neighbor’s individual dogs. Darwin saw species acquiring traits that became heritable when long-continued activities shaped selection pressures.

Jean Gayon repeated Mayr’s Lamarckian misreading of the identical quote from Origin of Species a decade later (1998 [1992]: 150).

Gayon is in the good company of many besides Huxley and Mayr. Science educators bemoan their failure to convince students that natural selection “does not involve effort, trying, or wanting” or “organisms trying to adapt” (Understanding Evolution, 2014). When their students accurately intuit that evolution has produced animals capable of effortful adaptation and these efforts can affect selection processes, this is considered “a significant departure from a scientific understanding of how animals change via natural selection” (Kelemen 2012: 71).

Huxley, Mayr, Gayon and science teachers stumbled over that ordinary and useful habit of thought, categorizing, while overlooking Darwin’s earnest doubts about the categories of his cultural inheritance (Beer 2009: xxx). The terms use and disusegrew into their common biological usage during the Lamarckian half-century that preceded Origin of Species. While Darwin was growing up, they acquired conceptual, social and political significance beyond concrete reference to specific animal activities. For many, the terms were synonymous with Lamarckian inheritance. Lamarckism has been called use-disuse theory.

When Darwin used these terms, he knew the importance of their secondary meanings for his readers. He also recognized the scientific and public relations merits of using these familiar terms for animal behavior in a more descriptive, pared down way.

Scientifically, he advanced more modest claims of animal agency than Lamarckian use of the terms. Darwin’s descriptive use of use and disuse created conceptual space for a developmental view of evolution that was not Lamarckian.

At the same time, Darwin wanted his readers to follow his argument and not give up on it. Pushing against the constraints of traditional terms by using them in nontraditional ways, Darwin’s “generous semantic practice” (Beer 2009: 33) allowed the reader to adjust their own yoke to the terms use and disuse. From his calibrated ambiguity, readers could hear in the text such Lamarckian overtones as their sensibilities favored.

Darwin’s semantic generosity quickened after publication of Origin of Species, as he responded to waves of criticism with a strategic retreat toward inclusiveness. In Variations of Animals and Plants under Domestication (1868), “anything which had been documented and accepted by a fellow scientist was included and assessed” (Vorzimmer 1963: 386). Darwin admitted for discussion a provisional hypothesis of Lamarckian inheritance that he had carefully avoided in Origin of Species. Darlington (1959: 41) complained that during this time “ambiguity … became the mode and standard of Darwin’s expression … which in the end soothed and satisfied the troubled world.”

As he changed successive editions of Origin of Species – to his wife Emma’s delight, adding “the Creator” in the second edition – Darwin remained committed to respectful, empirical inquiry that doubled as good public relations for his theory.

Bufflehead_taking_off

Bufflehead, Morro Bay State Park CA. by Kevin Cole 2008. http://commons.wikimedia.org/wiki/File:Male_Bufflehead_taking_off.jpg

While molecules eclipsed the behavior and development of whole organisms in 20th century evolutionary thought, accounts from Darwin’s vantage point persisted. Nobel physicist Erwin Schrödinger (1944: 113) echoed Darwin most clearly.

You simply cannot possess clever hands without using them for obtaining your aims… You cannot have efficient wings without attempting to fly… Selection would be powerless in ‘producing’ a new organ if selection were not aided all along by the organism’s making appropriate use of it….

Joining Huxley at Chicago’s centennial celebration of Origin of Species, Conrad Waddington (1959: 1636) presented a model of evolution that included animal choices.

Thus the animal by its behavior contributes in a most important way to determining the nature and intensity of the selective pressures which will be exerted on it.

Half a century on, Renée Duckworth (2009: 514) marked Origin’s sesquicentennial by reminding us that:

Changes in either the environment or an organism’s behavior can alter selection pressure. This places behavioral change on an equal footing with environmental change as a potential cause of evolutionary change … but despite the intuitive appeal of this idea, it remains largely unacknowledged in current evolutionary theory.

And Mary Jane West-Eberhard (2008: 902) rendered Darwin in contemporary terminology.

Much of Darwin’s discussion of … “use and disuse” refers not to Lamarckian inheritance but to what we would now call “phenotypic plasticity” [flexibility of the whole organism].

References

Beer, G. (2009). Darwin’s Plots (3rd ed.). Cambridge: Cambridge University Press.

Darlington, C. D. (1959). Darwin’s Place in History. Oxford: Basil Blackwell.

Darwin C. (1859) On the Origin of Species. In J. van Wyhe, ed. (2002), The Complete Work of Charles Darwin Online (http://darwin-online.org.uk).

Darwin, C. (1868). Variation of Animals and Plants Under Domestication. In J. van Wyhe, ed. (2002), The Complete Work of Charles Darwin Online (http://darwin-online.org.uk).

Duckworth, R. (2009). The role of behavior in evolution: A search for mechanism. Evolutionary Ecology 23: 513–531.

Gayon, J. (1992) [1998]. Darwin’s Struggle for Survival. Cambridge: Cambridge University Press.

Huxley, J. (1960). The emergence of Darwinism. In Evolution After Darwin, vol. I: The Evolution of Life, Sol Tax, ed., pages 1–21. Chicago: University of Chicago Press.

Kelemen, D. (2012). Teleological minds: How natural intuitions about agency and purpose influence learning about evolution. In Evolution Challenges: Integrating Research and Practice in Teaching and Learning about Evolution, Rosengren, K.S., S. K. Brem, E. M. Evans, and G. M. Sinatra, eds., pages 66–92. Oxford: Oxford University Press.

Mayr E. (1982). The Growth of Biological Thought. Cambridge: Harvard University Press.

Schrödinger E. (1944). What is Life? Cambridge: Cambridge University Press.

Understanding Evolution, University of California Museum of Paleontology, 01 January 2014 http://evolution.berkeley.edu/evolibrary/misconceptions_teacherfaq.php

Vorzimmer, P. (1963). Charles Darwin and blending inheritance.  Isis 543: 371–390.

Waddington, C. 1959 Evolutionary systems – animal and human. Nature 183 4676:1634-1638.

West-Eberhard, M. J. (2008) Toward a modern revival of Darwin’s theory of evolutionary novelty. Philosophy of Science 75: 899-908.


Tom Clark

As a psychologist, I have been interested in the role of behavior in evolution since my graduate training at the University of South Florida.

 

 

© 2015, Thomas L. Clark. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed in this article are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.

 


Darwin’s use of “use” and “disuse” (Part 1)

Tom Clark


Please note: this commentary, recovered on 8-Jan-2017, was originally published by the author, Tom Clark, on Science Dialogues on 28-Feb-2015.


LIKE OTHER NATURALISTS OF HIS DAY, Darwin thought that when animals used their bodies in some ways and not others, doing this and not that, these activities affected the evolution of their kind. Insect wings and rodent eyes became larger or smaller, more useful or less, depending on their ancestors’ use or disuse of their wings and eyes.

Unlike his peers, Darwin imagined animal behavior influencing evolution without Lamarckian inheritance of acquired characteristics. His most important discovery, natural selection, allowed him an alternative. Instead of direct transmission, from one generation to the next, of changes brought about by an animal’s activity within its lifetime, Darwin saw that such activity affects both how animals grow into adults—variation—and how natural selection plays out. And by way of long continued selection outcomes, characteristics expressed while growing up—specific variants—can become, somehow, more likely to develop in later generations. Hence, evolution.

Stretching to browse on trees did not cause giraffe ancestors to have offspring with longer necks. Rather, giraffe ancestors’ browsing habits swayed selection so giraffes that grew longer necks tended to have more offspring.

Giraffa_camelopardalis (5)

Photograph of Giraffa camelopardalis by Scott Harrison, Kruger Park 2006. http://commons.wikimedia.org/wiki/File:Giraffa_camelopardalis.JPG#file

Growing up mattered. Darwin observed variation among whole animals through their lifetimes, not variation among genes. Anything that made a growing child “not absolutely similar to the parent” was a source of variation that could make a difference in selection processes and outcomes (Darwin 1857). Darwin’s view was developmental, not Lamarckian.

Darwin understood that separating variation and selection was tidier in theory than in actual lives-in-progress. He took up his discussion of use and disuse in a chapter called “Laws of Variation” with a subheading “Use and disuse, combined with natural selection” (Darwin 1859: 131, italics added). What animals did with whom was a central and natural aspect of selection, as well as a source of variation. Animal behavior comprised and induced variation that was grist for selection and also part of the mill.

So he shows us in Origin of Species (1859: 136–143) that “the wings of some of the insects have been enlarged, and the wings of others have been reduced by natural selection aided by use and disuse.”

The wingless condition of so many Madeira beetles is mainly due to the action of natural selection, but combined probably with disuse.

And,

The eyes of some burrowing rodents are rudimentary in size… probably due to gradual reduction from disuse, but aided perhaps by natural selection . . . natural selection would constantly aid the effects of disuse.

So,

On the whole, I think we may conclude that habit, use, and disuse, have, in some cases, played a considerable part in the modification . . . of various organs; but that the effects of use and disuse have often been largely combined with, and sometimes overmastered by, the natural selection of innate differences.

Animals were protagonists in Darwin’s evolutionary plots. Theirs was an unwitting participation, animal intentions being of evolution, not about evolution. Still, animals’ semi-autonomous activities affected the evolution of their own kind and of others who came to their attention. Darwin saw, for example, that arbitrary “aesthetic” preferences of pollinating insects—going to these flowers more than those—affected selection of the flowers and of the insect’s nose, used to reach that flower’s nectar.

Darwin concerned himself with mechanisms of biological inheritance but had limited evidence to go on. Mendel published his experiments on plant hybridization in 1865 but with just three citations in 35 years, they never came to Darwin’s attention. Though he eventually proposed a Lamarckian mechanism of inheritance in his “provisional” hypothesis of pangenesis, Darwin continued to view the role of animal behavior in evolution as more developmental than Lamarckian. Animal activity naturally “either checked or favored” selection (1868: 234).

His developmental view of evolution endured August Weismann discerning a “barrier” between somatic and germ cells. Weismann’s famous barrier, allowing transmission of only germ cells to the next generation, was the death knell for Lamarckism. Yet Weismann affirmed Darwin’s view that “use and disuse” affected evolution by way of natural selection.

Weismann contrasted “mere disuse” with its consequence that “natural selection ceases to act” (1889: 15–16). By this relaxation of selection, disuse induced evolutionary change. Regarding use,

. . .  the direct influence of increased use during the course of a single life [cannot] produce hereditary effects without the assistance of natural selection (1889: 91).

And with the assistance of natural selection, it can.

. . . the use and disuse of parts can have no direct share in the process. . . . The fact, however, that we deny the transmission of the effects of use and disuse, does not imply that these factors are of no importance. . . . both use and disuse may lead indirectly to variations . . .  [that change selection processes and outcomes] (Weismann 1893: 395–396).

Darwin’s developmental view fell to the margins of evolutionary thought with the rediscovery of Mendel’s experiments that began the 20th century and initiated its turn toward a molecular gaze. In an historic cultural shift dubbed “bath-waterism” (Ewer 1960: 162), evolutionary thought threw out, along with the bath water of Lamarckism, the whole organism as an agent of evolutionary change. Evolutionary science transformed our image of ourselves from protagonists in the story of life to products of natural laws and chance, from the result of ancestors’ doings to the result of chemical happenings.

Our story changed from processes of selection that naturally had the benefit of vision and other senses and capabilities for the past 600 million years to “blind” selection the whole way; from an understanding that manners maketh the man, and action maketh the organism, to an understanding that tiny entities inside us make us who we are; from a story at the scale of organisms and lifetimes to a story about molecules across eons; from a story that includes growing up to a story that moves from one adult generation to the next by incantations of genes, environments and their so-called “interactions” (genes, of course, interact only with intra-cellular environments); from plot without humans to humans without plot; from a story teeming with human agency and meaning to a story of eggs regarding chickens as merely a way to make more eggs; from a story that tells us of life’s expanding autonomy, so what we do matters, to a story that tells us choice is a comforting illusion so we have no say in the course nature takes.

Among the ideas slanting these images of ourselves has been a misreading of Darwin’s use of use and disuse as simply Lamarckian.

References

Darwin, C. (1857). Letter to Asa Gray, 5 Sept. http://www.darwinproject.ac.uk/entry-2136.

Darwin C. (1859). On the Origin of Species. In J. van Wyhe, ed., (2002), The Complete Work of Charles Darwin Online (http://darwin-online.org.uk).

Darwin, C. (1868). Variation of Animals and Plants under Domestication. In J. van Wyhe, ed., (2002), The Complete Work of Charles Darwin Online (http://darwin-online.org.uk).

Ewer, R. F. 1960 Natural selection and neoteny. Acta Biotheoretica13:161-184.

Weismann, A. (1889). Essays Upon Heredity. Oxford: Clarendon Press.

Weismann, A. (1893). The Germ Plasm. New York: Scribner.


Tom Clark

As a psychologist, I have been interested in the role of behavior in evolution since my graduate training at the University of South Florida.

 

 

© 2015, Thomas L. Clark. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The statements and opinions expressed in this article are those of the author(s) and do not constitute official statements or positions of the Editors and others associated with SCIENCE DIALOGUES.