Co-nutrient limitation of diatom growth under nitrogen or silicon limitation. A reply to the paper of Flynn and Martin-Jezequel

Flynn and Martin-Jézéquel (J. Plankton Res., 22,447–472, 2000) derived a mechanistic model for nitrogenand silicon physiology of diatoms. During their analysis, theycompared the output of this model with that of the co-nutrientmodel of Davidson and Gurney (J. Plankton Res., 21, 839–858,1999). They highlighted some discrepancies between the predictionsof the two models, which occurred subsequent to exhaustion ofthe yield-limiting nutrient, and suggested that the co-nutrientmodel contained technical inaccuracies in its output. Here itis shown that by simply modifying the numerical values of twoof the parameters of the co-nutrient model, while retainingexactly the same model structure, it is possible to producesimilar dynamics to those exhibited by the model of Flynn andMartin-Jézéquel.     

Ectogenesis: a reply to Singer and Wells

The possibility of achieving ectogenesis, or the growing of a human fetus to term in an artificial womb, is approaching reality as a result of advances in treatment of premature newborns and in in vitro fertilization techniques. In their 1984 book, The Reproductive Revolution, issued in North America as Making Babies, Peter Singer and Deane Wells offered several arguments for ectogenesis. James examines their arguments and rejects two of them, that ectogenesis offers a less problematic alternative to surrogate motherhood, and that ectogenesis could make it possible to reconcile fetal rights with the right to abortion on demand. He grants Singer and Wells' argument that the childless have a claim to state support of their desire to nurture, but contends that government-supported ectogenesis should still be rejected because the adoption of unwanted children is a preferable alternative to the use of an exotic, expensive, and still unproven technology.     

Conjecture and explanation: A reply to Reydon

Reydon (2012) comments on my account of how-possibly explanation (Forber, 2010). I distinguish between three types of explanation (global how-possibly, local how-possibly, and how actually) and argue that these distinctions track various roles explanations play in evolutionary biology. While Reydon accepts the distinctions, he questions whether the two different types of how-possibly explanation count as genuine explanations. He summarizes his analysis with a slogan: “global how-possibly explanations are explanations but not how-possibly; local explanations are how-possibly but not explanations.” Reydon’s commentary raises a number of insightful points, and I will not be able to address them all. Instead, after clarifying certain points in my original paper (4 1), I will respond to Reydon’s slogan by addressing whether global how-possibly explanations should count as explaining how possible (4 2), and what (so-called) local how-possibly explanations are, if not explanations (4 3).     

Non-therapeutic modification and self-interest: reply to Schramme

In this article I reply to Thomas Schramme's argument that there are no good reasons for the prohibition of severe forms of voluntary non‐therapeutic body modification. I argue that on paternalistic assumptions there is, in fact, a perfectly good reason.     

Measurable notions of complexity and their relationship to biological complexity

Complexity is often invoked as a motivation for a systems approach to biology. We review three measurable notions of complexity from the areas of computation and data analysis. These measures have each led to mathematical theory and to further insight on the complexity of objects, demonstrating the benefits of having a well-defined measure of complexity. Each measure is applicable in the study of particular biological systems; however, none is satisfactory to serve as a universal measure of biological complexity. The study of biological systems will likely require numerous measures of complexity, each appropriate for analysis in specific settings.     

Genotype to phenotype: associations,errors and complexity

The Keystone Symposium on Genotype to Phenotype: Focus on Disease was held in Santa Fe, New Mexico, USA, from 19 to 24 February 2002.     

Animal signals: A reply to Hinde

Hinde has criticized articles by Dawkins & Krebs (1978) and Caryl (1979) in which supposedly traditional ethological views about agonistic display were contrasted with those arising from games theory. It is argued here that the views that we contrasted with those from games theory were not ‘straw men’: in particular, Cullen's view is completely incompatible with the predictions from games theory, and is well supported by ethological evidence (as conventionally interpreted). But an unusually detailed analysis of the ethological data, which raises many points for future studies, shows that the evidence actually favours the games theoretic view. Hinde argues that the conflict hypothesis of threat display implies that displays could not and should not carry precise information. The arguments he used in this context are not wholly satisfactory: in particular, explanations in terms of interaction are of little value unless details of the interaction can be specified. Clear hypotheses are needed in the analysis of animal communication, and ideas from games theory can be of help to ethology in this respect.