Linnaeus and the invisible world

Linnaeus expressed his fascination for microscopy in his work Mundum Invisibilem 1767 (the invisible world), which was one of the very first attempts to bring light and order to the microscopic discoveries of the time. Linnaeus wrote about his only microscopic experiment in the same publication. He wanted to know where to place the fungi in his grand 'Systema Naturae', but misinterpreted the results of the experiment completely. This is perhaps one of Linnaeus' greatest and least known mistakes, but one that somehow boosted development anyway.
We took the original microscope models used by Linnaeus, took photos, and compared them with images obtained with modern instruments. Our experiments revealed several new findings, and let us understand why Linnaeus made his mistake. One other finding is that Linnaeus must have used the most modern and advanced compound microscope of his time, a large Cuff microscope in his experiment. Only two large microscopes by Cuff were available in Sweden by the time. A large Cuff microscope was found in Sweden lately. This microscope is probably the actual instrument that Linnaeus used.     

Some early works on heliconiine butterflies and their biology (Lepidoptera, Nymphalidae)

In the course of a survey of the history of the study of Heliconiinae, particularly their biology, in the eighteenth and nineteenth centuries it is shown that Heliconius nigromarginatus (Goeze) and H. pallescens (Goeze) are nomina oblita , and that H. cinereofuscus (Goeze) is not, as always supposed, a species in its own right. A new name is proposed for H. melpomene cybele (Cramer). The origin and application of some of Linnaeus' names is discussed.
Illustrations of Heliconius by Seba, Clerck, Petiver and Cramer show that three species, melpomene, erato and doris have been polymorphic at least since the middle of the eighteenth century.
The Indo-Australian genus Cethosia should probably be included in the Heliconiinae.     

Design and construction of "synthetic species"

Synthetic biology is an area of biological research that combines science and engineering. Here, I merge the principles of synthetic biology and regulatory evolution to create a new species with a minimal set of known elements. Using preexisting transgenes and recessive mutations of Drosophila melanogaster, a transgenic population arises with small eyes and a different venation pattern that fulfils the criteria of a new species according to Mayr's Biological Species Concept. The population described here is the first transgenic organism that cannot hybridize with the original wild type population but remains fertile when crossed with other identical transgenic animals. I therefore propose the term "synthetic species" to distinguish it from "natural species", not only because it has been created by genetic manipulation, but also because it may never be able to survive outside the laboratory environment. The use of genetic engineering to design artificial species barriers could help us understand natural speciation and may have practical applications. For instance, the transition from transgenic organisms towards synthetic species could constitute a safety mechanism to avoid the hybridization of genetically modified animals with wild type populations, preserving biodiversity.     

Linnaeus's natural and artificial arrangements of plants

Linnaeus's artificial and natural arrangements of plants are examined using a Spearman rank coefficient (which is explained) on his presentations of his own and others' arrangements in the Classes plantarum and elsewhere. There is little alteration in his successive artificial arrangements. In contrast, between 1751 and 1764 his natural arrangements changed considerably, partly in the sequences of genera within orders but mostly by rearrangement of the orders. Comparison with Cesalpino's and Ray's natural arrangements, using the longest-recognized natural groups as signposts, suggests that Linnaeus in his latest natural arrangement (1764) approximated more closely to Ray's. Examination of Linnaeus's successive treatments of certain groups (palms, Zingiberaceae, Hydrocharis-Stratiotes-Vallisneria) and of Giseke's exposition of Linnaeus's lectures on natural groups (1792) shows that Linnaeus was much influenced by habitus and vegetative characters as well as those of the fructification. He recognized orders consisting of a chain of genera linked successively by overall affinity and without any single diagnostic character. Where possible, he preferred characters of the fructification and his ‘secret’ consulting of the habitus is explained as secondary to such characters. It is suggested that in his latest arrangement he approximated more to a scala naturae, as he probably did in zoology about the same time. Within his artificial arrangements Linnaeus kept to sequences of genera as natural as possible. He realized that some groups in his natural arrangements were still artificial, and his aphorism that all genera and species are natural, classes and orders part natural and part artificial, refers to his and others' practice until the natural system could be completed. It is not a statement of the essential natures of these ranks. Linnaeus's distinction in practice between natural and artificial arrangements was less clear-cut than Sachs believed. Linnaeus's rejection of the ancient tree/herb division was empirical, not a reasoned repudiation of an a priori grouping. The tree/herb division could be upheld in his day as obviously natural, not merely accepted on authority.     

Marine biological collections in the 21st century

From the time of Linnaeus forward, it has been appreciated that collections, not least marine biological collections, are fundamental to the understanding of the biodiversity of life on earth, especially when they contain type specimens which define individual species. Historical collections are particularly rich in types and also represent a model of the biodiversity of marine life at the time of the collection, often centuries ago. The taxonomic and systematic importance of collections is well appreciated, as is the significance of time series of data in this period of anthropogenic environmental change. The application of new techniques increases the value of collected material even further, for example, molecular biology techniques allowing the recognition of new (often cryptic) taxa and their distributions, and stable isotope analyses releasing information on past and present ontogenies, geographical distributions and diets. Moreover the new era of information technology with associated digitization enables the release of the information stored in the collections to the scientists of the world.     

Rank and sequence in Caspar Bauhin's Pinax

CAIN, A. J., 1994. Rank and sequence in Caspar Bauhin's Pinax. Bauhin's consistent use of genera, species and binominals, applauded by historians as anticipating Linnaeus's theory and practice, does not appear on closer examination to be intended as anything of the sort. His use of the terms genus and species is as in Aristotelian logic, with a shifting reference, at all taxonomic levels. His typographical layout, emphasizing (but far from invariably employing) single-word names for effectively generic entities, often qualified by ‘and its species’, gives the impression of Linnaean practice, and coincides with it not infrequently, but not with Linnaean theory. The main entities for which it can be said that Bauhin uses fairly consistently a biverbal binominal name-phrase, like Linnaeus' trivial names, were in fact in Linnaeus's eyes two levels of supraspecific groupings. The main entities in Bauhin which Linnaeus recognized as species, as is shown by his quotations in the Species plantarum, are subdivisions of his biverbally or nearly biverbally named groupings, but themselves have multiverbal names. These correspond closely to Linnaeus's diagnostic specific names, not at all to his biverbal trivial names. Bauhin probably had no conception of the species and genus as ranks in the modern sense, first adumbrated by Tournefort and utilized by Linnaeus. Bauhin certainly tried to group forms by natural affinity, as did Theophrastus before him and Linnaeus afterwards. Not being alerted to the importance of the details of the flower and fruit, he used what characters he could find, notably, but not by any means exclusively, leaf shape. He composed the Pinax as a nomenclatural concordance to earlier authors, notably Dioscorides, Theophrastus and Pliny. He retained the sequence of major groups of Theophrastus (as the greatest authority on plants) but reversed it to start with the best-known plants, grasses. Where Theophrastus gave no help, in the cryptogams, Bauhin inserted as a pendant his own series from ferns down to fungi, using the Aristotelian principles of the gradation of forms. His overall arrangement, therefore, is not a simple progression but a chain with pendants. Bauhin is far closer to earlier authors than to Linnaeus, but his typography, along with other authors, may well have helped to incite Linnaeus to a more rigorous and consistent use of ranked groups and biverbal names.     

The evolution of the animals: introduction to a Linnean tercentenary celebration

Celebrating 300 years since the birth of Carl Linnaeus (1707-1778), a meeting was held in June 2007 to review recent progress made in understanding the origins and evolutionary radiation of the animals. The year 2008 celebrates the 250th anniversary of the publication of the 10th edition of Linnaeus' Systema Naturae, generally considered to be the starting point of zoological nomenclature. With subsequent advances in comparative taxonomic and systematic studies, Darwin's discovery of evolution by natural selection, the birth of phylogenetic systematics, and the wider interest in biodiversity, it is salutary to consider that many of the major advances in our understanding of animal evolution have been made in recent years. Phylogenetic systematics, drawing from evidence provided by genotype, phenotype and an understanding of the link between them through comparative embryological and evolutionary developmental studies, has provided a wide consensus of the major branching patterns of the tree of life. More importantly, the integrated approaches discussed in the 16 contributions to this volume highlight the identity and nature of problematic taxa, the missing data, errors in existing analytical procedures and the promise of a wealth of additional characters from genomes that need to be accumulated and assessed in providing a definitive Systema Naturae.     

Rupert Riedl and the re-synthesis of evolutionary and developmental biology: body plans and evolvability

This paper reviews the scientific career of Rupert Riedl and his contributions to evolutionary biology. Rupert Riedl, a native of Vienna, Austria, began his career as a marine biologist who made important contributions to the systematics and anatomy of major invertebrate groups, as well as to marine ecology. When he assumed a professorship at the University of North Carolina in 1968, the predominant thinking in evolutionary biology focused on population genetics, to the virtual exclusion of most of the rest of biology. In this atmosphere Riedl developed his "systems theory" of evolution, which emphasizes the role of functional and developmental integration in limiting and enabling adaptive evolution by natural selection. The main objective of this theory is to account for the observed patterns of morphological evolution, such as the conservation of body plans. In contrast to other "alternative" theories of evolution, Riedl never denied the importance of natural selection as the driving force of evolution, but thought it necessary to contextualize natural selection with the organismal boundary conditions of adaptation. In Riedl's view development is the most important factor besides natural selection in shaping the pattern and processes of morphological evolution.     

Solving the Wolbachia paradox: modeling the tripartite interaction between host, Wolbachia, and a natural enemy

Wolbachia is one of the most common symbionts of arthropods. Its establishment requires lateral transfer to and successful transmission within novel host species. However, Wolbachia performs poorly when introduced into new host species, and models predict that Wolbachia should seldom be able to establish from low initial frequencies. Recently, various symbionts, including Wolbachia, have been shown to protect their hosts from natural enemies. Hence, Wolbachia invasion may be facilitated by the dynamic interaction between it, its host, and a natural enemy. We model such an interaction whereby Wolbachia induces either complete resistance, partial resistance, or tolerance to a host-specific pathogen and also induces the common manipulation phenotype of cytoplasmic incompatibility (CI). We show that the presence of the pathogen greatly facilitates Wolbachia invasion from rare and widens the parameter space in which "imperfect" Wolbachia strains can invade. Furthermore, positive frequency-dependent selection through CI can drive Wolbachia to very high frequencies, potentially excluding the pathogen. These results may explain a poorly understood aspect of Wolbachia biology: it is widespread, despite performing poorly after transfer to new host species. They also support the intriguing possibility that Wolbachia strains that encode both CI and natural-enemy resistance could potentially rid insects, including human disease vectors, of important pathogens.     

Tools and challenges for diversity-driven proteomics in Brazil

Our current knowledge in biology has been mostly derived from studying model organisms and cell lines in which only a small fraction of all described species have been extensively studied. Although these model organisms are amenable to genetic manipulations, this blinds researchers to the true variability of life. Groundbreaking discoveries are often achieved by analyzing "noncanonical" species; for example, the characterization of Taq polymerase from Thermus aquaticus ultimately led to a revolution in the field of molecular biology. Brazil possesses a rich biodiversity and a considerable fraction of Brazilian groups use current proteomic techniques to explore this natural treasure-trove. However, in our opinion, much more than the widely adopted peptide spectrum match approach is required to explore this rich "proteomosphere." Here, we provide a critical overview of the available strategies for the analysis of proteomic data from "noncanonical" biological samples (e.g. proteins from unsequenced genomes or genomes with high levels of polymorphisms), and demonstrate some limitations of existing approaches for large-scale protein identification and quantitation. An understanding of the premises behind these computational tools is necessary to properly deal with their limitations and draw accurate conclusions.     

Phylogeny,fossils, and model systems in the study of evolutionary developmental biology

The emerging field of evolutionary developmental biology (evo-devo) continues to operate largely under a single paradigm. In this paradigm developmental regulatory genes and processes are compared among a collection of "model organisms" selected primarily on the basis of their historical utility in the study of development. This approach has proven to be extremely informative, revealing an unexpected deep evolutionary conservation among developmental genes and genetic systems. Despite its success, concern has been expressed regarding its limitations. We discuss the "model organism" paradigm in evo-devo research. Based on our interpretation of its limitations, we propose a separate but complementary approach that is centered on "model groups." These groups are selected on the basis of their taxonomic affinity and their relevance to questions of interest to evo-devo biologists. We further discuss the Tetraodontiformes (Teleostei, Pisces) as an example of a "model group" for the evo-devo study of vertebrate skeletal elements.     

Choosing a mate in a high predation environment: Female preference in the fiddler crab Uca terpsichores

The interplay between a receiver's sensory system and a sender's courtship signals is fundamental to the operation of sexual selection. Male courtship signals that match a female receiver's preexisting perceptual biases can be favored yet the message they communicate is not always clear. Do they simply beacon the male's location or also indicate his quality? We explored this question in a species of fiddler crab Uca terpsichores that courts under elevated predation risk and that mates and breeds underground in the safety of males' burrows. Sexually receptive females leave their own burrows and are thereby exposed to avian predators as they sequentially approach several courting males before they choose one. Males court by waving their single greatly enlarge claw and sometimes by building a sand hood next to their burrow entrance. Hoods are attractive because they elicit a risk‐reducing orientation behavior in females, and it has been suggested that claw waving may also serve primarily to orient the female to the male. If the wave communicates male quality, then females should discriminate mates on the basis of variation in elements of the wave, as has been shown for other fiddler crabs. Alternatively, variation in elements of the claw waving display may have little effect on the display's utility as a beacon of the location of the male and his burrow. We filmed courting males and females under natural conditions as females responded to claw waving and chose mates. Analysis of the fine‐scale courtship elements between the males that females rejected and those they chose revealed no differences. When predation risk during courtship is high, males' courtship displays may serve primarily to guide females to safe mating and breeding sites and not as indicators of male quality apart from their roles as beacons.     

The species of "Ichneumon" (Hymenoptera) described by Linnaeus

Ichneumonidae in the Linnaean and other collections have been critically assessed with regard to their status as type-specimens of species described by Linnaeus. The generic placements of the 56 nominal species of Ichneumonidae (54 originally in Ichneumon and two in Mutilla) described by Linnaeus are established after study of the extant type-material. Lectotypes are designated for eleven of the species and one new synonymy is established. Notes are given on the 33 species originally described by Linnaeus in Ichneumon but now placed in other families.     

AnOistodus venustus-like conodont species from the Middle Ordovician of Baltoscandia

Ordovician conodont specimens resemblingOistodus venustus Stauffer, 1935 have been reported from many areas. There is increasing evidence, however, that several lineages with homeomorphic conodont elements have erroneously been referred to one and the same species. I have investigated Baltoscandian conodont elements of this kind in order to find out about their origins and phylogenetic relationships with morphologically comparable elements from other areas. A natural grouping of finds from the Middle and lower Upper Ordovician of Baltoscandia is here described as belonging to a new species of a new genus,Venoistodus balticus n. gen., n. sp. The new species probably evolved paedomorphically fromDrepanoistodus forceps (Lindström, 1955) in the Early Ordovician.     

Cain on Linnaeus: the scientist-historian as unanalysed entity

Zoologist A. J. Cain began historical research on Linnaeus in 1956 in connection with his dissatisfaction over the standard taxonomic hierarchy and the rules of binomial nomenclature. His famous 1958 paper ‘Logic and Memory in Linnaeus's System of Taxonomy’ argues that Linnaeus was following Aristotle's method of logical division without appreciating that it properly applies only to ‘analysed entities’ such as geometric figures whose essential nature is already fully known. The essence of living things being unanalysed, there is no basis on which to choose the right characters to define a genus nor on which to differentiate species. Yet Cain's understanding of Aristotle, which depended on a 1916 text by H. W. B. Joseph, was fatally flawed. In the 1990s Cain devoted himself to further historical study and softened his verdict on Linnaeus, praising his empiricism. The idea that Linnaeus was applying an ancient and inappropriate method cries out for fresh study and revision.     

Can natural selection favour altruism between species?

Darwin suggested that the discovery of altruism between species would annihilate his theory of natural selection. However, it has not been formally shown whether between‐species altruism can evolve by natural selection, or why this could never happen. Here, we develop a spatial population genetic model of two interacting species, showing that indiscriminate between species helping can be favoured by natural selection. We then ask if this helping behaviour constitutes altruism between species, using a linear‐regression analysis to separate the total action of natural selection into its direct and indirect (kin selected) components. We show that our model can be interpreted in two ways, as either altruism within species, or altruism between species. This ambiguity arises depending on whether or not we treat genes in the other species as predictors of an individual's fitness, which is equivalent to treating these individuals as agents (actors or recipients). Our formal analysis, which focuses upon evolutionary dynamics rather than agents and their agendas, cannot resolve which is the better approach. Nonetheless, because a within‐species altruism interpretation is always possible, our analysis supports Darwin's suggestion that natural selection does not favour traits that provide benefits exclusively to individuals of other species.