Search results for "Comparative biology"
showing 4 items of 4 documents
The worldwide variation in avian clutch size across species and space.
2008
Traits such as clutch size vary markedly across species and environmental gradients but have usually been investigated from either a comparative or a geographic perspective, respectively. We analyzed the global variation in clutch size across 5,290 bird species, excluding brood parasites and pelagic species. We integrated intrinsic (morphological, behavioural), extrinsic (environmental), and phylogenetic effects in a combined model that predicts up to 68% of the interspecific variation in clutch size. We then applied the same species-level model to predict mean clutch size across 2,521 assemblages worldwide and found that it explains the observed eco-geographic pattern very well. Clutches a…
Histones, Their Variants and Post-translational Modifications in Zebrafish Development.
2020
Complex multi-cellular organisms are shaped starting from a single-celled zygote, owing to elaborate developmental programs. These programs involve several layers of regulation to orchestrate the establishment of progressively diverging cell type-specific gene expression patterns. In this scenario, epigenetic modifications of chromatin are central in influencing spatiotemporal patterns of gene transcription. In fact, it is generally recognized that epigenetic changes of chromatin states impact on the accessibility of genomic DNA to regulatory proteins. Several lines of evidence highlighted that zebrafish is an excellent vertebrate model for research purposes in the field of developmental ep…
The comparative biology of the closely related Senecio nebrodensis and S. viscosus, a narrow endemic and a widespread ruderal
1993
The closely related Senecio nebrodensis, a perennial herb from four mountain ranges in Spain, and S. viscosus, an annual herb widespread in Europe, are being compared by the study of herbarium material and comparative cultivation. In cultivation, S. nebrodensis behaved as an annual, completing its life cycle within a shorter period of time than S. viscosus. The formation of basal leaf rosettes is much more pronounced in S. nebrodensis than in S.viscosus. The main difference between the two species, however, is their breeding system. While S. nebrodensis is self-incompatible, S. viscosus is self-compatible. Differences in reproductive morphology (mainly size and number of ray florets) are su…
Introduction to Symposium: Poecilogony--A Window on Larval Evolutionary Transitions in Marine Invertebrates
2012
Poecilogony is the intraspecific variation in developmental mode that has been described in some marine invertebrates. Poecilogonous species produce different larval forms (e.g., free-swimming planktotrophic larvae as well as brooded lecithotrophic or adelphophagic larvae). Poecilogony can be a controversial topic, since it is difficult to identify and characterize the phenomenon with certainty. It has been challenging to determine whether poecilogony represents developmental polymorphism with a genetic basis or developmental polyphenism reflecting plastic responses to environmental cues. Other outstanding questions include whether common mechanisms underlie the developmental variation we o…