Mega-evolutionary dynamics of the adaptive radiation of birds

The origin and expansion of biological diversity is regulated by both developmental trajectories and limits on available ecological niches. As lineages diversify, an early and often rapid phase of species and trait proliferation gives way to evolutionary slow- downs as new species pack into ever more densely occupied regions of ecological niche space. Small clades such as Darwin’s finches demonstrate that natural selection is the driving force of adaptive radiations, but how microevolutionary processes scale up to shape the expansion of phenotypic diversity over much longer evolutionary timescales is unclear. Here we address this problem on a global scale by analysing a crowd-sourced dataset of three-dimensional scanned bill morphology from more than 2,000 species. We find that bill diversity expanded early in extant avian evolutionary history, before transitioning to a phase dominated by packing of morphological space. However, this early phenotypic diversification is decoupled from temporal variation in evolutionary rate: rates of bill evolution vary among lineages but are comparatively stable through time. We find that rare, but major, discontinuities in phenotype emerge from rapid increases in rate along single branches, sometimes leading to depauperate clades with unusual bill morphologies. Despite these jumps between groups, the major axes of within-group bill-shape evolution are remarkably consistent across birds. We reveal that macroevolutionary processes underlying global-scale adaptive radiations support Darwinian and Simpsonian ideas of microevolution within adaptive zones and accelerated evolution between distinct adaptive peaks

The Development of Inclusive Learning Relationships in Mainstream Settings: A Multimodal Perspective

The debate regarding the inclusion of children with Special Educational Needs and Disabilities (SEND) in mainstream education in the UK partly revolves around what makes the classroom environment inclusive. Through the potential offered by the specific qualitative methodologies employed, this study aimed to explore the development of teachers’ pedagogical practices and learning relationships upon the inclusive education of children with special educational needs and disabilities in two primary school classes. The study considered the views and behaviours of primary school pupils with and without special educational needs, primary school teachers and teaching assistants (TAs) in one mainstream school. Drawing on a multimodal approach to discourse analysis to account for the complex relationships between symbolic and non-verbal modes of classroom signification, the study explored how meaning is produced in classrooms and children’s modes of communication, as well as in teachers’ practices. The two classes are compared on the basis of teaching observations, interviews, transcripts of dialogues, and analyses of classroom organisation and decoration. This paper suggests that the greatest influence on the educational and social outcomes of students with special educational needs is the behaviour and practices of the classroom teacher

Dense sampling of bird diversity increases power of comparative genomics (vol 587, pg 252, 2020)

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