The origin of marine invertebrate larvae has been an area of controversy in developmental evolution for over a century. Here, we address the question of whether a pelagic “larval” or benthic “adult” morphology originated first in metazoan lineages by testing the hypothesis that particular gene co-option patterns will be associated with the origin of feeding, indirect developing larval forms. Empirical evidence bearing on this hypothesis is derivable from gene expression studies of the sea urchin larval gut of two closely related (...) but differently developing congenerics, Heliocidaris tuberculata (feeding indirect-developing larva) and H. erythrogramma (nonfeeding direct developer), given two subsidiary hypotheses. (1) If larval gut gene expression in H. tuberculata was co-opted from an ancestral adult expression pattern, then the gut expression pattern will remain in adult H. erythrogramma despite its direct development. (2) Genes expressed in the larval gut of H. tuberculata will not have a coordinated expression pattern in H. erythrogramma larvae due to loss of a functional gut. Five structural genes expressed in the invaginating archenteron of H. tuberculata during gastrulation exhibit substantially different expression patterns in H. erythrogramma with only one remaining endoderm specific. Expression of these genes in the adult of H. erythrogramma and larval gut of H. tuberculata, but not in H. erythrogramma larval endoderm, supports the hypothesis that they first played roles in the formation of adult structures and were subsequently recruited into larval ontogeny during the origin and evolution of feeding planktotrophic deuterostome larvae. (shrink)

The authors claim that disciplinary epistemologies—disciplinary habits of mind and ways of thinking—offer productive lenses for observing teaching practices. Furthermore, they argue that educational developers who draw from multiple epistemologies in combination provide rich evidence with regard to teaching and learning and can speak to academic colleagues from an array of disciplines. Clarity is provided for career paths in educational development for colleagues from academic disciplines who are contemplating part‐ or full‐time work in a teaching center. The authors hope that (...) this opening collection develops into a toolkit and area of inquiry about disciplinary approaches to the practice of educational development. (shrink)

Many years ago Wilamowitz desiderated a systematic collection of the texts which relate to the different types of poetry composed by the great lyric poets of Greece. He hoped that if we could only crystallize our admittedly scanty information about the characteristics of, say, the Paean or the Dirge, we might be able to reach a slightly better understanding than we have now of the formal structure and artistic design of the poems and fragments which have come down to us (...) under these titles. Indeed, this kind of knowledge is very important. (shrink)

This is a clear assessment of Hume's theories of the self and personal identity, including his famous Treatise on Human Nature . Pitson provides a critical exploration of his thinking, also examining the continuing relevance of Hume's theories for contemporary philosophy and relating it to his broader reflections on human nature itself. Divided into two parts, Pitson's study follows Hume's important distinction between two aspects of personal identity: the "mental" and the "agency". The first part discusses Hume's conception of the (...) mind as a "bundle" or "system" of perceptions and explores Hume's position on the traditional mind/body problem. In the second part Pitson examines a range of topics including Hume's treatment of character, the relationship between human and animal nature, and the nature of agency. (shrink)