Cada aspecto de la visión, desde las proteínas de opsina hasta los ojos y las formas en que sirven al comportamiento animal, es increíblemente diverso. Solo con una perspectiva evolutiva se puede comprender y apreciar plenamente esta diversidad. En esta revisión, describo y explico la diversidad en cada nivel y trato de transmitir una comprensión de cómo el origen de la primera ops en hace unos 800 millones de años pudo iniciar la avalancha que produjo la asombrosa diversidad de ojos y visiones que vemos hoy. A pesar de la diversidad, muchos tipos de fotorreceptores, ojos y roles visuales han evolucionado varias veces de forma independiente en diferentes animales, revelando un patrón de evolución ocular estrictamente guiado por limitaciones funcionales e impulsado por la evolución de comportamientos gradualmente más exigentes.

BACKGROUNDThe interdisciplinary field of animal coloration is growing rapidly, spanning questions about the diverse ways that animals use pigments and structures to generate color, the underlying genetics and epigenetics, the perception of color, how color information is integrated with information from other senses, and general principles underlying color’s evolution and function. People working in the field appreciate linkages between these parallel lines of enquiry, but outsiders need the easily navigable roadmap that we provide here. ADVANCESIn the past 20 years, the field of animal coloration research has been propelled forward by technological advances that include spectrophotometry, digital imaging, computational neuroscience, innovative laboratory and field studies, and large-scale comparative analyses, which are allowing new questions to be asked. For example, we can now pose questions about the evolution of camouflage based on what a prey’s main predator can see, and we can start to appreciate that gene changes underlying color production have occurred in parallel in unrelated species. Knowledge of the production, perception, and evolutionary function of coloration is poised to make contributions to areas as diverse as medicine, security, clothing, and the military, but we need to take stock before moving forward. OUTLOOKHere, a group of evolutionary biologists, behavioral ecologists, psychologists, optical physicists, visual physiologists, geneticists, and anthropologists review this diverse area of science, daunting to the outsider, and set out what we believe are the key questions for the future. These are how nanoscale structures are used to manipulate light; how dynamic changes in coloration occur on different time scales; the genetics of coloration (including key innovations and the extent of parallel changes in different lineages); alternative perceptions of color by different species (including wavelengths that we cannot see, such as ultraviolet); how color, pattern, and motion interact; and how color works together with other modalities, especially odor. From an adaptive standpoint, color can serve several functions, and the resulting patterns frequently represent a trade-off among different evolutionary drivers, some of which are nonvisual (e.g., photoprotection). These trade-offs can vary between individuals within the same population, and color can be altered strategically on different time scales to serve different purposes. Lastly, interspecific differences in coloration, sometimes even observable in the fossil record, give insights into trait evolution. The biology of color is a field that typifies modern research: curiosity-led, technology-driven, multilevel, interdisciplinary, and integrative.

Aposematic signals are often characterized by high conspicuousness. Larger and brighter signals reinforce avoidance learning, distinguish defended from palatable prey and are more easily memorized by predators. Conspicuous signalling, however, has costs: encounter rates with naive, specialized or nutritionally stressed predators are likely to increase. It has been suggested that intermediate levels of aposematic conspicuousness can evolve to balance deterrence and detectability, especially for moderately defended species. The effectiveness of such signals, however, has not yet been experimentally tested under field conditions. We used dough caterpillar-like baits to test whether reduced levels of aposematic conspicuousness can have survival benefits when predated by wild birds in natural conditions. Our results suggest that, when controlling for the number and intensity of internal contrast boundaries (stripes), a reduced-conspicuousness aposematic pattern can have a survival advantage over more conspicuous signals, as well as cryptic colours. Furthermore, we find a survival benefit from the addition of internal contrast for both high and low levels of conspicuousness. This adds ecological validity to evolutionary models of aposematic saliency and the evolution of honest signalling.

Frequency-dependent predation may maintain or prevent colour pattern polymorphisms in prey, and can be caused by a variety of biological phenomena, including perceptual processes (search images), optimal foraging and learning. Most species are preyed upon by more than one predator species, which are likely to differ in foraging styles, perceptual and learning abilities. Depending upon the interaction between predator vision, background and colour pattern parameters, certain morphs may be actively maintained in some conditions and not in others, even with the same predators. More than one kind of predator will also affect stability, and only slight changes in conditions can cause a transition between polymorphism and monomorphism. Frequency-dependent selection is not a panacea for the explanation of variation in animal colour patterns, although it may be important in some systems.

Many organisms use warning, or aposematic, coloration to signal their unprofitability to potential predators. Aposematically colored prey are highly visually conspicuous. There is considerable empirical support that conspicuousness promotes the effectiveness of the aposematic signal. From these experiments, it is well documented that conspicuous, unprofitable prey are detected sooner and aversion learned faster by the predator as compared with cryptic, unprofitable prey. Predators also retain memory of the aversion longer when prey is conspicuous. The present study focused on the elements of conspicuousness that confer these benefits of aposematic coloration. Drawing on current understanding of animal vision, we distinguish 2 features of warning coloration: high chromatic contrast and high brightness, or luminance, contrast. Previous investigations on aposematic signal efficacy have focused mainly on the role of high chromatic contrast between prey and background, whereas little research has investigated the role of high luminance contrast. Using the Chinese mantid as a model predator and gray-painted milkweed bugs as model prey, we found that increased prey luminance contrast increased detection of prey, facilitated predator aversion learning, and increased predator memory retention of the aversive response. Our results suggest that the luminance contrast component of aposematic coloration can be an effective warning signal between the prey and predator. Thus, warning coloration can even evolve as an effective signal to color blind predators.

Demonstrations of interactions between diverse selective forces on bright coloration in defended species are rare. Recent work has suggested that not only do the bright colours of Neotropical poison frogs serve to deter predators, but they also play a role in sexual selection, with females preferring males similar to themselves. These studies report an interaction between the selective forces of mate choice and predation. However, evidence demonstrating phenotypic discrimination by potential predators on these polymorphic species is lacking. The possibility remains that visual (avian) predators possess an inherent avoidance of brightly coloured diurnal anurans and purifying selection against novel phenotypes within populations is due solely to non-random mating. Here, we examine the influence of predation on phenotypic variation in a polymorphic species of poison frog, Dendrobates tinctorius. Using clay models, we demonstrate a purifying role for predator selection, as brightly coloured novel forms are more likely to suffer an attack than both local aposematic and cryptic forms. Additionally, local aposematic forms are attacked, though infrequently, indicating ongoing testing/learning and a lack of innate avoidance. These results demonstrate predator-driven phenotypic purification within populations and suggest colour patterns of poison frogs may truly represent a ‘magic trait’

Demonstrations of interactions between diverse selective forces on bright coloration in defended species are rare. Recent work has suggested that not only do the bright colours of Neotropical poison frogs serve to deter predators, but they also play a role in sexual selection, with females preferring males similar to themselves. These studies report an interaction between the selective forces of mate choice and predation. However, evidence demonstrating phenotypic discrimination by potential predators on these polymorphic species is lacking. The possibility remains that visual (avian) predators possess an inherent avoidance of brightly coloured diurnal anurans and purifying selection against novel phenotypes within populations is due solely to non-random mating. Here, we examine the influence of predation on phenotypic variation in a polymorphic species of poison frog, Dendrobates tinctorius. Using clay models, we demonstrate a purifying role for predator selection, as brightly coloured novel forms are more likely to suffer an attack than both local aposematic and cryptic forms. Additionally, local aposematic forms are attacked, though infrequently, indicating ongoing testing/learning and a lack of innate avoidance. These results demonstrate predator-driven phenotypic purification within populations and suggest colour patterns of poison frogs may truly represent a ‘magic trait’.

An experiment was performed to assess the relative survival of two forms of 5th instar larvae of Lygaeus equestris (Heteroptera, Lygaeidae) — the normal red form, called aposematic, and a mutant grey form, called cryptic — when given to hand-raised great tits (Parus major).Sixteen birds were presented with aposematic larvae and 16 were presented with cryptic larvae in 10 consecutive trials. One attack per trial was allowed. Both larval forms were presented against a background matching the grey larvae, but since both prey types were presented in a specific place known to the predator, detection rate for both was assumed to be unity.Birds learned to avoid both prey types. However, the survival of the aposematic larvae was higher than that of the cryptic ones due to three aspects of predator behaviour: i) a greater initial reluctance to attack, ii) a more rapid avoidance learning, and iii) a lower frequency of killing in an attack, when the prey was aposematic. Moreover, a greater number of birds learned to avoid prey without killing any individual, when the prey was aposematic. This result is considered to be due to prey coloration alone, since, in a separate test, no difference in prey distastefulness could be detected.This experiment shows that individual prey can benefit from being aposematic and indicates that individual selection can be a sufficient explanation for the evolution of aposematic coloration. It was concluded that, since the survivorship was 6.4 times higher for the aposematic prey, it could have a detection rate that is correspondingly higher than the cryptic in order for the two forms to have equal fitness.

The theory of warning signals dates back to Wallace but is still confusing, controversial and complex. Because predator avoidance of warningly coloured prey (aposematism) is based upon learning and reinforcement, it is difficult to understand how initially rare conspicuous forms subsequently become common. Here, we discuss several possible resolutions to this apparent paradox. Many of these ideas have been largely ignored as a result of implicit assumptions about predator behaviour and assumed lack of variation in the predators, prey and the predation process. Considering the spatial and temporal variation in and mechanisms of behaviour of both predators and prey will make it easier to understand the process and evolution of aposematism.

The question, “Why should prey advertise their presence to predators using warning coloration?” has been asked for over 150 years. It is now widely acknowledged that defended prey use conspicuous or distinctive colors to advertise their toxicity to would-be predators: a defensive strategy known as aposematism. One of the main approaches to understanding the ecology and evolution of aposematism and mimicry (where species share the same color pattern) has been to study how naive predators learn to associate prey’s visual signals with the noxious effects of their toxins. However, learning to associate a warning signal with a defense is only one aspect of what predators need to do to enable them to make adaptive foraging decisions when faced with aposematic prey and their mimics. The aim of our review is to promote the view that predators do not simply learn to avoid aposematic prey, but rather make adaptive decisions about both when to gather information about defended prey and when to include them in their diets. In doing so, we reveal what surprisingly little we know about what predators learn about aposematic prey and how they use that information when foraging. We highlight how a better understanding of predator cognition could advance theoretical and empirical work in the field.

Evolution via natural selection has continually shaped the coloration of numerous organisms. One coloration of particular importance is the eyespot: a phylogenetically widespread, conspicuous marking that has been shown to effectively reduce predation, often through its resemblance to the eye. Although widely studied, most research has been experimental in nature. We approach eyespots using a comparative phylogenetic framework that is global in scope. Herein, we identify the potential drivers of eyespot evolution in coral reef fishes; essentially the rules that govern their appearance in this group of organisms. We surveyed 2664 reef fish species (42% of all described reef fish species) and found that eyespots are present in approximately one in every 10 species. Most eyespots occur in closely related species and have been present in some families for over 50 million years. Focusing on damselfishes (family: Pomacentridae) as a study group, we reveal that eyespots are rare in planktivorous species, which is likely driven by the predation risk associated with their feeding location. Using a heatmapping technique, we also show that the location of eyespots is fundamentally different in active fishes that swim above the benthos vs. cryptobenthic fishes that rest on the benthos. These location differences may reflect different functions of eyespots among reef fish species.

We analyze the structural elements which comprise a standard scientific paper. Previous analysis generally has focused on one element of a paper at a time. However, the title, author list, affiliation, abstract, text, tables, graphs, charts, photographs and references all represent possible data resources for investigation. After specifying those elements, we focus successively on the history, normative tradition, and sociological analysis of a selection of those elements.

Scientific knowledge constitutes a complex system that has recently been the topic of in-depth analysis. Empirical evidence reveals that little is known about the dynamic aspects of human knowledge. Precise dissection of the expansion of scientific knowledge could help us to better understand the evolutionary dynamics of science. In this paper, we analyzed the dynamic properties and growth principles of the MEDLINE bibliographic database using network analysis methodology. The basic assumption of this work is that the scientific evolution of the life sciences can be represented as a list of co-occurrences of MeSH descriptors that are linked to MEDLINE citations. The MEDLINE database was summarized as a complex system, consisting of nodes and edges, where the nodes refer to knowledge concepts and the edges symbolize corresponding relations. We performed an extensive statistical evaluation based on more than 25 million citations in the MEDLINE database, from 1966 until 2014. We based our analysis on node and community level in order to track temporal evolution in the network. The degree distribution of the network follows a stretched exponential distribution which prevents the creation of large hubs. Results showed that the appearance of new MeSH terms does not also imply new connections. The majority of new connections among nodes results from old MeSH descriptors. We suggest a wiring mechanism based on the theory of structural holes, according to which a novel scientific discovery is established when a connection is built among two or more previously disconnected parts of scientific knowledge. Overall, we extracted 142 different evolving communities. It is evident that new communities are constantly born, live for some time, and then die. We also provide a Web-based application that helps characterize and understand the content of extracted communities. This study clearly shows that the evolution of MEDLINE knowledge correlates with the network’s structural and temporal characteristics.

The NLM Catalog provides access to NLM bibliographic data for journals, books, audiovisuals, computer software, electronic resources and other materials. Links to the library's holdings in LocatorPlus, NLM's online public access catalog, are also provided.

One way to think about "core" biodiversity data is as a network of connected entities, such as taxa, taxonomic names, publications, people, species, sequences, images, and collections that form the "biodiversity knowledge graph". Many questions in biodiversity informatics can be framed as paths in this graph. This article explores this futher, and sketches a set of services and tools we would need in order to construct the graph. New information In order to build a usable biodiversity knowledge graph we should adopt JSON-LD for biodiversity data, develop reconciliation services to match entities to identifiers, and a use a mixture of document and graph databases to store and query the data. To bootstrap this project we can create wrappers around each major biodiversity data provider, and a central cache that is both a document store and a simple graph database. This power of this approach should be showcased by applications that use the central cache to tackle specific problems, such as augmenting existing data.

The success of distributed and semantic-enabled systems relies on the use of up-to-date ontologies and mappings between them. However, the size, quantity and dynamics of existing ontologies demand a huge maintenance effort pushing towards the development of automatic tools supporting this laborious task. This article proposes a novel method, investigating different types of similarity measures, to identify concepts’ attributes that served to define existing mappings. The obtained experimental results reveal that our proposed method allows to identify the relevant attributes for supporting mapping maintenance, since we found correlations between ontology changes affecting the identified attributes and mapping changes.

As the amount of scholarly communication increases, it is increasingly difficult for specific core scientific statements to be found, connected and curated. Additionally, the redundancy of these statements in multiple fora makes it difficult to determine attribution, quality, and provenance. To tackle these challenges, the Concept Web Alliance has promoted the notion of nanopublications (core scientific statements with associated context). In this document, we present a model of nanopublications along with a NamedGraph/RDF serialization of the model. Importantly, the serialization is defined completely using already existing community developed technologies. Finally, we discuss the importance of aggregating nano-publications and the role that the ConceptWiki plays in facilitating it.

SKOS—Simple Knowledge Organization System—provides a model for expressing the basic structure and content of concept schemes such as thesauri, classification schemes, subject heading lists, taxonomies, folksonomies, and other similar types of controlled vocabulary. As an application of the Resource Description Framework (RDF), SKOS allows concepts to be composed and published on the World Wide Web, linked with data on the Web and integrated into other concept schemes. This document is a user guide for those who would like to represent their concept scheme using SKOS. In basic SKOS, conceptual resources (concepts) are identified with URIs, labeled with strings in one or more natural languages, documented with various types of note, semantically related to each other in informal hierarchies and association networks, and aggregated into concept schemes. In advanced SKOS, conceptual resources can be mapped across concept schemes and grouped into labeled or ordered collections. Relationships can be specified between concept labels. Finally, the SKOS vocabulary itself can be extended to suit the needs of particular communities of practice or combined with other modeling vocabularies. This document is a companion to the SKOS Reference, which provides the normative reference on SKOS.

https://doi.org/10.3855/jidc.12600