scholarly journals Further twists in gastropod shell evolution

2008 ◽  
Vol 4 (2) ◽  
pp. 179-182 ◽  
Author(s):  
Reuben Clements ◽  
Thor-Seng Liew ◽  
Jaap Jan Vermeulen ◽  
Menno Schilthuizen
Keyword(s):  
Evolutionary Biology ◽  
Logarithmic Spiral ◽  
Spiral Growth ◽  
Evolutionary Perspective ◽  
Gastropod Shell ◽  
Form And Function ◽  
Evolutionary Origins ◽  
Taxonomic Groups ◽  
And Function ◽  
Shell Coiling

The manner in which a gastropod shell coils has long intrigued laypersons and scientists alike. In evolutionary biology, gastropod shells are among the best-studied palaeontological and neontological objects. A gastropod shell generally exhibits logarithmic spiral growth, right-handedness and coils tightly around a single axis. Atypical shell-coiling patterns (e.g. sinistroid growth, uncoiled whorls and multiple coiling axes), however, continue to be uncovered in nature. Here, we report another coiling strategy that is not only puzzling from an evolutionary perspective, but also hitherto unknown among shelled gastropods. The terrestrial gastropod Opisthostoma vermiculum sp. nov. generates a shell with: (i) four discernable coiling axes, (ii) body whorls that thrice detach and twice reattach to preceding whorls without any reference support, and (iii) detached whorls that coil around three secondary axes in addition to their primary teleoconch axis. As the coiling strategies of individuals were found to be generally consistent throughout, this species appears to possess an unorthodox but rigorously defined set of developmental instructions. Although the evolutionary origins of O. vermiculum and its shell's functional significance can be elucidated only once fossil intermediates and live individuals are found, its bewildering morphology suggests that we still lack an understanding of relationships between form and function in certain taxonomic groups.

scholarly journals On a bender—BARs, ESCRTs, COPs, and finally getting your coat

2011 ◽  
Vol 193 (6) ◽  
pp. 963-972 ◽  
Author(s):  
Mark C. Field ◽  
Andrej Sali ◽  
Michael P. Rout
Keyword(s):  
Comparative Genomics ◽  
Protein Complexes ◽  
Eukaryotic Cell ◽  
Intracellular Membrane ◽  
Membrane Systems ◽  
Profound Impact ◽  
Form And Function ◽  
Evolutionary Origins ◽  
And Function ◽  
Internal Architecture

Tremendous variety in form and function is displayed among the intracellular membrane systems of different eukaryotes. Until recently, few clues existed as to how these internal membrane systems had originated and diversified. However, proteomic, structural, and comparative genomics studies together have revealed extensive similarities among many of the protein complexes used in controlling the morphology and trafficking of intracellular membranes. These new insights have had a profound impact on our understanding of the evolutionary origins of the internal architecture of the eukaryotic cell.

scholarly journals Convergence in form and function overcomes non-parallel evolutionary histories in a Holarctic fish

2018 ◽  
Author(s):  
Arne Jacobs ◽  
Madeleine Carruthers ◽  
Andrey Yurchenko ◽  
Natalia V. Gordeeva ◽  
Sergei S. Alekseyev ◽  
...  
Keyword(s):  
Evolutionary Biology ◽  
Salvelinus Alpinus ◽  
Arctic Charr ◽  
Parallel Evolution ◽  
Genetic Associations ◽  
Form And Function ◽  
Selection Variable ◽  
And Function ◽  
Phenotypic Parallelism ◽  
Evolutionary Lineages

AbstractUnderstanding the extent to which evolution is predictable under multifarious selection is a longstanding question in evolutionary biology. However, the interplay of stochastic and contingent factors influencing the extent of parallelism in nature is not well understood. To test the predictability of evolution, we studied a ‘natural experiment’ on different organismal levels across lakes and evolutionary lineages of a freshwater salmonid fish, Arctic charr (Salvelinus alpinus). We identified significant phenotypic parallelism between Arctic charr ecotype pairs within a continuum of parallel evolution and highly parallel adaptive morphological traits. Variability in phenotypic predictability was explained by complex demographic histories, differing genomic backgrounds and genomic responses to selection, variable genetic associations with ecotype, and environmental variation. Remarkably, gene expression was highly similar across ecotype replicates, and explained the observed parallelism continuum. Our findings suggest that parallel evolution by non-parallel evolutionary routes is possible when the regulatory molecular phenotype compensates for divergent histories.

Form and Function of Facial Expressive Origins

2017 ◽  
Author(s):  
Daniel H. Lee ◽  
Adam K. Anderson
Keyword(s):  
Facial Expressions ◽  
Social Communication ◽  
Visual Information ◽  
Mental States ◽  
Form And Function ◽  
Evolutionary Origins ◽  
Functional Perspective ◽  
Sensory Effects ◽  
And Function ◽  
Communicative Role

Facial expressions are an important source of social communication. But we do not know why they appear the way they do and how they arose. Here we discuss evidence supporting Darwin’s theory that our expressions originated for sensory egocentric function for the expresser, which were then co-opted as signals for allocentric social function. We show that facial expressions of fear and disgust have distinct opposing sensory effects that serve each emotion’s theorized function, regulating the intake of nasal and visual information. Then, we show how such egocentrically adaptive expressive forms may have been socially co-opted for allocentric function, transmitting basic gaze signals and complex mental states adaptively congruent for the receiver as the expresser. Together, the evidence connects the appearance of our expressions from their evolutionary origins to their modern-day communicative role, providing a functional perspective for organizing and understanding expression forms.

Section 2 Summary—Functional Morphology and Ecology of Larval Forms

2018 ◽  
Keyword(s):  
Life History ◽  
Functional Morphology ◽  
Morphological Variation ◽  
Aquatic Environment ◽  
Molecular Variation ◽  
Form And Function ◽  
Life History Stages ◽  
Taxonomic Groups ◽  
And Function ◽  
Exogenous Nutrients

Larvae are intermediate life history stages between embryos and juvenile and/or reproductive stages, but this characteristic is about the only feature that unites the incredible diversity of larval forms. The majority of larval forms evolved in the sea and exhibit tremendous morphological, physiological, and molecular variation, many of which are potential adaptations to match form and function in the context of the aquatic environment. The three chapters in this section review how larvae from different taxonomic groups sort through and ingest exogenous nutrients and how environmental variation elicits morphological variation....

scholarly journals The evolutionary origins of antagonistic neurotrophin signaling

2017 ◽  
Vol 216 (5) ◽  
pp. 1223-1225 ◽  
Author(s):  
Austin B. Keeler ◽  
Christopher D. Deppmann
Keyword(s):  
Nervous System ◽  
Effector Proteins ◽  
Competitive Balance ◽  
Form And Function ◽  
Evolutionary Origins ◽  
Survival Pathways ◽  
Toll Receptor ◽  
And Function ◽  
Neurotrophin Signaling ◽  
Receptor Family

A competitive balance between constructive and destructive developmental cues governs both the form and function of the vertebrate nervous system. In this issue, Foldi et al. (2017. J. Cell Biol. https://doi.org/10.1083/jcb.201607098) explore the evolutionary origins of these cues and report that in Drosophila melanogaster pro- and mature neurotrophins are capable of inducing death and survival pathways, respectively, by binding Toll receptor family members, which then recruit distinct sets of effector proteins.

Avian Diversity: Speciation, Macroevolution, and Ecological Function

2020 ◽  
Vol 51 (1) ◽  
pp. 533-560 ◽  
Author(s):  
Joseph A. Tobias ◽  
Jente Ottenburghs ◽  
Alex L. Pigot
Keyword(s):  
Evolutionary Biology ◽  
Biological Diversity ◽  
Functional Trait ◽  
Functional Ecology ◽  
Bird Diversity ◽  
Data Sets ◽  
Evolutionary Origins ◽  
Integrative Studies ◽  
And Function ◽  
Biology Research

The origin, distribution, and function of biological diversity are fundamental themes of ecology and evolutionary biology. Research on birds has played a major role in the history and development of these ideas, yet progress was for many decades limited by a focus on patterns of current diversity, often restricted to particular clades or regions. Deeper insight is now emerging from a recent wave of integrative studies combining comprehensive phylogenetic, environmental, and functional trait data at unprecedented scales. We review these empirical advances and describe how they are reshaping our understanding of global patterns of bird diversity and the processes by which it arises, with implications for avian biogeography and functional ecology. Further expansion and integration of data sets may help to resolve longstanding debates about the evolutionary origins of biodiversity and offer a framework for understanding and predicting the response of ecosystems to environmental change.

scholarly journals Mechanical sensitivity reveals evolutionary dynamics of mechanical systems

2015 ◽  
Vol 282 (1804) ◽  
pp. 20143088 ◽  
Author(s):  
P. S. L. Anderson ◽  
S. N. Patek
Keyword(s):  
Evolutionary Biology ◽  
Evolutionary Dynamics ◽  
Morphological Changes ◽  
Morphological Diversity ◽  
Mechanical Sensitivity ◽  
Minimal Impact ◽  
Form And Function ◽  
Form Function ◽  
And Function ◽  
Four Bar Linkage

A classic question in evolutionary biology is how form–function relationships promote or limit diversification. Mechanical metrics, such as kinematic transmission (KT) in linkage systems, are useful tools for examining the evolution of form and function in a comparative context. The convergence of disparate systems on equivalent metric values (mechanical equivalence) has been highlighted as a source of potential morphological diversity under the assumption that morphology can evolve with minimal impact on function. However, this assumption does not account for mechanical sensitivity—the sensitivity of the metric to morphological changes in individual components of a structure. We examined the diversification of a four-bar linkage system in mantis shrimp (Stomatopoda), and found evidence for both mechanical equivalence and differential mechanical sensitivity. KT exhibited variable correlations with individual linkage components, highlighting the components that influence KT evolution, and the components that are free to evolve independently from KT and thereby contribute to the observed pattern of mechanical equivalence. Determining the mechanical sensitivity in a system leads to a deeper understanding of both functional convergence and morphological diversification. This study illustrates the importance of multi-level analyses in delineating the factors that limit and promote diversification in form–function systems.

Scanning tunneling microscopy (STM) of DNA and RNA

1989 ◽  
Vol 47 ◽  
pp. 34-35
Author(s):  
Patricia G. Arscott ◽  
Gil Lee ◽  
Victor A. Bloomfield ◽  
D. Fennell Evans
Keyword(s):  
Molecular Structures ◽  
Inorganic Materials ◽  
Resolving Power ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Form And Function ◽  
Dna And Rna ◽  
Calf Thymus ◽  
And Function ◽  
The Relationship

STM is one of the most promising techniques available for visualizing the fine details of biomolecular structure. It has been used to map the surface topography of inorganic materials in atomic dimensions, and thus has the resolving power not only to determine the conformation of small molecules but to distinguish site-specific features within a molecule. That level of detail is of critical importance in understanding the relationship between form and function in biological systems. The size, shape, and accessibility of molecular structures can be determined much more accurately by STM than by electron microscopy since no staining, shadowing or labeling with heavy metals is required, and there is no exposure to damaging radiation by electrons. Crystallography and most other physical techniques do not give information about individual molecules.We have obtained striking images of DNA and RNA, using calf thymus DNA and two synthetic polynucleotides, poly(dG-me5dC)·poly(dG-me5dC) and poly(rA)·poly(rU).

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