Phenotypic Plasticity

The ocelot, Leopardus pardalis, is a medium-sized Neotropical felid with a relatively wide geographical distribution. Across their range, ocelots exhibit clinal variation in pattern and color of pelage. Despite this variation, few aberrant genetic morphs have been documented. This record describes the first apparent leucistic variant for the ocelot: a white female with black markings that was treed on three occasions over a 3-year period in the transitional Chaco of western Paraguay.

It is commonly accepted that within-population phenotypic variation is caused by genotypic and environmental heterogeneity. Non-genotypic variation is thought to result from diversity of environmental conditions alone. This however contradicts experimental data showing that even when both genetic and environmental sources of phenotypic variation are neglected, residual variation still exists. This residual phenotypic variation is caused by deviations of developmental trajectories from the target trajectory determined for particular genotype and environment, i.e. by developmental instability. This variation is well-known for morphological traits where it is measured most often by fluctuating asymmetry, i.e. random deviations from perfect symmetry, which can be easily separated from the other type of phenotypic variation. In morphological characters which do not possess symmetry or in non-morphological characters this variation cannot usually be separated from other type of non-genotypic variation, caused by environmental heterogeneity. Most researchers still believe that all non-genotypic variation, even under standardised experimental conditions, is caused by insufficient standardization of environment, rather than by other sources of phenotypic variation. When special efforts are undertaken to analyse variation caused by developmental instability, this variation contributes substantially to non-genotypic variation. To exemplify how variation caused by developmental instability can be separated from phenotypic plasticity we analysed phenotypic variation of resting egg formation in Daphnia pulicaria. The proportion of females carrying resting eggs has been shown to depend on the photoperiod of their mothers, revealing transgeneration effects . Developmental instability manifests itself in differences between clonemates within an experimental vessel in a standardized environment. Some females produce resting eggs whereas others do not. Our estimations based on results obtained in experimental conditions and extrapolation to conditions in the wild showed that phenotypic plasticity, i.e. phenotypic response to changes of day duration in maternal environment (phenotypic plasticity) explains only 1-2% of phenotypic variation whereas developmental instability explains approximately 98-99% of phenotypic variance of this trait (i.e. producing or not producing resting eggs), if other factors causing phenotypic plasticity are absent. This example demonstrates a major role of developmental instability in variation of the trait under study. The contribution of developmental instability to phenotypic variation should be considered in studying evolutionary patterns of phenotypic traits.

The role of phenotypic plasticity in evolution has historically been a contentious issue because of debate over whether plasticity shields genotypes from selection or generates novel opportunities for selection to act. Because plasticity encompasses diverse adaptive and non-adaptive responses to environmental variation, no single conceptual framework adequately predicts the diverse roles of plasticity in evolutionary change. 2. Different types of phenotypic plasticity can uniquely contribute to adaptive evolution when populations are faced with new or altered environments. Adaptive plasticity should promote establishment and persistence in a new environment, but depending on how close the plastic response is to the new favoured phenotypic optimum dictates whether directional selection will cause adaptive divergence between populations. Further, non-adaptive plasticity in response to stressful environments can result in a mean phenotypic response being further away from the favoured optimum or alternatively increase the variance around the mean due to the expression of cryptic genetic variation. The expression of cryptic genetic variation can facilitate adaptive evolution if by chance it results in a fitter phenotype. 3. We conclude that adaptive plasticity that places populations close enough to a new phenotypic optimum for directional selection to act is the only plasticity that predictably enhances fitness and is most likely to facilitate adaptive evolution on ecological timescales in new environments. However, this type of plasticity is likely to be the product of past selection on variation that may have been initially non-adaptive. 4. We end with suggestions on how future empirical studies can be designed to better test the importance of different kinds of plasticity to adaptive evolution.

The hydroid and the medusa of Zanclea costata, together with their cnidome, are described from a rich population living on the shells of the bivalves Chamelea galina and Spisula subtruncata from the Ligurian Sea. The high phenotypic plasticity of the hydranth of this species confirms the use of the cnidome as the main reliable feature for species identification within the genus Zanclea.

Two different Calanus finmarchicus (Gunnerus) cohorts originating from 60°N (Bergen) and 69°N (Tromsø) were investigated in equal environmental conditions to study their different physiological responses to the same environment. A two-plus-two-bag mesocosm study was carried out between March and July 1998, in Håkøybotn, Tromsø, in order to determine development and mortality rates of the two parallel cohorts of C. finmarchicus. For practical reasons, the cohort from Bergen was incubated 10 days earlier than the Tromsø cohort. Consequently, they were exposed to elevated food conditions as compared to the Tromsø cohort. A high initial mortality among the Bergen cohort could clearly be ascribed, by genetic discrimination, to "contamination" with C. helgolandicus. After this initial mass mortality, the mortality was constantly 0.03–0.04 day−1. In cohorts starting from naupliar stage I, there was no significant difference in development or growth, the median development time (NI–CIV) differing by only 7 days (~6%). The difference in development time can be explained to a large extent (~4 days) by temperature differences. This is substantiated with model simulations using a physiological model developed for C. finmarchicus. There was a time lag in incubation between the two cohorts, resulting in elevated temperature during incubation of the Tromsø cohort. A fraction of both cohorts differentiated sexually at stage CV, with males differentiating before females. Females from both cohorts produced eggs, but specific egg production differed significantly (P>0.001, t-test). This was supported by elevated RNA:DNA ratio in females from the Bergen cohort. Both cohorts demonstrated quite similar development and physiological growth rates and, consequently, are considered to belong to the same genetic population inhabiting the Norwegian Shelf. The study demonstrates that C. finmarchicus is capable of adaptation to changes in environment and, thereby, demonstrates a significant physiological plasticity.

Trade-offs between acquisition capacities for aboveground and belowground resources were investigated by studying the phenotypic plasticity of leaf and root traits in response to different irradiance levels at low nutrient supply. Two congeneric grasses with contrasting light requirements, Dactylis glomerata and D. polygama, were used. The aim was to analyze phenotypic covariation in components of leaf area and root length in response to above-and belowground resource limitation and the consequences of this variation for resource acquisition and plant growth. At intermediate shading (30 and 20% of full sunlight) the plants were able to maintain their total root length, despite a strongly increased total leaf area and a reduced biomass allocation to roots. This was associated with an unaltered or slightly increased nutrient uptake and growth. At 5.5% relative irradiance, growth was severely reduced, especially in the shade-tolerant D. polygama. The results show that constraints on acquisition capacities for aboveground and belowground resources, caused by biomass allocation, may be alleviated by plasticity in other traits such as tissue-mass density and thickness of roots and leaves. The results also suggest different adaptive constraints for phenotypic plasticity and for genetically determined interspecific variation. Phenotypic plasticity tends to maximize resource acquisition and growth rate in the short term, whereas the higher tissue-mass density and the longer leaf life-span of shade-tolerant species indicate reduced loss rates as a more advantageous speciesspecific adaptation to shade in the long term.

Plant morphological adjustment in response to spatial resource heterogeneity is an important factor that determines the outcomes of plant-plant and plant-environment interactions. In this study, a dynamic model of resource allocation and growth partitioning at the whole-plant level is presented. The aim is to suggest a mechanism by which plants are capable of modifying their resource allocation to favour the growth of their growing parts sited in resource-rich patches. In this model, an individual plant is treated as a population of relatively independent subunits competing for internal resources. The growth decision of individual shoot and root subunits depends on their local endogenous nutrient status. The allocation of nutrients to different shoot parts and root parts is determined by the structure of the vascular networks. No specific partitioning functions and driving coefficients are introduced in the model to coordinate resource allocation and growth partitioning at the whole-plant level. Vascular tissues acquire resources from the nutrient flow passing through them to grow and maintain their activities. The simulation results show that, based on simple rules of nutrient supply, transport and utilization, plants are able to integrate activities at the whole-plant level to allocate proportionally more growth to their growing parts in the most favourable positions.

Only recently, variability within individuals has become of importance to evolutionary thinking. The boom in the literature on behavioural variability has led to the emergence of concepts such as behavioural plasticity, stereotypy, imprecision, and intra-individual variability (IIV). The proliferation of new terms has resulted in overlapping concepts, spreading confusion in understanding the origins of variability.

Phenotypic plasticity is the capability of a genotype to produce different phenotypes in different environments. Previous studies have indicated phenotypic variability in asexual, male, and female reproduction in Botryllus schlosseri, a hermaphroditic, colonial ascidian, but not explicitly tested for genotype by environment interactions that indicate genetic variation in plastic responses. Consequently, clones derived from an estuarine population were deployed at their native site and a warmer, higher productivity site 10 km up-river. Male reproduction was assayed by testis size, female reproduction by the number of eggs produced, and asexual reproduction by colony growth rate. To test for ontogenetic effects, data were collected from two different generations of zooids born in the field. Analyses of variance indicated plasticity in asexual and female reproduction during the first zooid generation and plasticity in all three traits during the third zooid generation. Reaction norms v...

Phenotypic plasticity and microevolution are the two primary means by which organisms respond adaptively to local conditions. While these mechanisms are not mutually exclusive, their relative magnitudes will influence both the rate of, and ability to sustain, phenotypic responses to climate change. We review accounts of recent phenotypic changes in wild mammal populations with the purpose of critically evaluating the following: (i) whether climate change has been identified as the causal mechanism producing the observed change; (ii) whether the change is adaptive; and (iii) the relative influences of evolution and/or phenotypic plasticity underlying the change. The available data for mammals are scant. We found twelve studies that report changes in phenology, body weight or litter size. In all cases, the observed response was primarily due to plasticity. Only one study (of advancing parturition dates in American red squirrels) provided convincing evidence of contemporary evolution. Subsequently, however, climate change has been shown to not be the causal mechanism underlying this shift. We also summarize studies that have shown evolutionary potential (i.e. the trait is heritable and/or under selection) in traits with putative associations with climate change and discuss future directions that need to be undertaken before a conclusive demonstration of plastic or evolutionary responses to climate change in wild mammals can be made.

We describe the age structures of two neighbouring terrestrial salamander populations. The skeletochronological method was also used on larvae in utero and on new-born individuals. The age of adults was 8±24 years in population A, while males reached maturity at 3±5 years old and the youngest females were 6 years old in population B. Males and females from population B were also larger than those in population A. For the ®rst time, lines of arrested growth (LAGs) were also found in the humerus of intra-uterine larvae and new-born individuals, indicating that young can spend up to 3 years in utero (population B) and up to 4 years (population A) before hatching. Growth of adults (®tted by the Bertalanffy model) also exhibited differences in growth coef®cient ( k ) and mean asymptotic length (SVL max ) between sexes and populations. Local climatic conditions differed between the two areas of these populations and we hypothesize that the number of rainy days directly in¯uences foraging during the short period of activity (< 3 months), leading to a delay in age at maturity, smaller length and growth rate, and increased gestation duration in the drier environment. The discussion is focused on proximate environmental in¯uences on the variation of length and associated life-history traits in ectotherms, especially in terrestrial salamanders.

Facultative paedomorphosis is an environmentally induced polymorphism that results in the coexistence of mature, gilled, and fully aquatic paedomorphic adults and transformed, terrestrial, metamorphic adults in the same population. This polymorphism has been of interest to scientists for decades because it occurs in a large number of caudate amphibian taxa as well as in a large diversity of habitats. Numerous experimental and observational studies have been conducted to explain the proximate and ultimate factors affecting these heterochronic variants in natural populations. The production of each alternative phenotype is based on a genotyperenvironment interaction and research suggests that differences in the environment can produce paedomorphs through several ontogenetic pathways. No single advantage accounts for the maintenance of this polymorphism. Rather, the interplay of different costs and benefits explains the success of the polyphenism across variable environments. Facultative paedomorphosis allows individuals to cope with habitat variation, to take advantage of environmental heterogeneity in the presence of open niches, and to increase their fitness. This process is expected to constitute a first step towards speciation events, and is also an example of biodiversity at the intraspecific level. The facultative paedomorphosis system is thus ripe for future studies encompassing ecology, evolution, behaviour, endocrinology, physiology, and conservation biology. Few other systems have been broad enough to provide varied research opportunities on topics as diverse as phenotypic plasticity, speciation, mating behaviour, and hormonal regulation of morphology. Further research on facultative paedomorphosis will provide needed insight into these and other important questions facing biologists.

In urban environments, long-term tree survival and performance requires physiological tolerance or phenotypic plasticity in plant functional traits. Knowledge of these traits can inform the likely persistence of urban forests under future, more severe climates. We assessed the plasticity of morphological and physiological traits of tree species planted along an urban climatic gradient in the Greater Sydney region during a severe, multi-year drought in eastern Australia. We selected four sites along a~55 km east-west transect, ranging from the cool/wet coast to the warm/dry inland. We assessed five tree species (four natives, one exotic) with different predicted climatic vulnerability based on climate-origins, estimating functional traits indicative of drought tolerance: carbon isotope composition (δ 13 C), Huber value (HV), specific leaf area (SLA), wood density (WD), and leaf turgor loss point (π tlp). Broadly, trees planted in warm/dry sites had more negative π tlp , higher WD, δ 13 C and HV, and lower SLA than cool/wet sites, indicating phenotypic plasticity to drought. The leaf-level traits π tlp , δ 13 C and SLA were more strongly correlated with temperature and precipitation, compared to HV and WD. Species differed in the extent of their trait shifts along the transect, with greater plasticity evident in the exotic Celtis australis and the more temperate cool-climate Tristaniopsis laurina, compared to the more tropical, warm-climate Cupaniopsis anacardioides, which showed limited plasticity and lower drought tolerance. Our findings reveal adaptive capacity of urban trees to climate via plasticity in drought tolerance traits, which can direct species selection to improve urban forests resistance to climate change.

Hominin evolutionary history is characterized by regular dispersals, cycles of colonization, and entry into novel environments. This article considers the relationship between such colonizing capacity and hominin biology. In general, colonizing strategy favors rapid rates of reproduction and generalized rather than specialized biology. Physiological viability across diverse environments favors a high degree of phenotypic plasticity, which buffers the genome from selective pressures. Colonizing also favors the capacity to access and process information about environmental variability. We propose that early hominin adaptive radiations were based upon the development of such capacities as adaptations to unstable Pliocene environments. These components came together, along with fundamental changes in morphology, behavior, and cognition in the genus Homo, who exploited them in subsequent wider dispersals. Middle Pleistocene hominins and modern humans also show development of further traits, which correspond with successful probing of, and dispersals into, stressful environments. These traits have their precursors in primate or ape biology, but have become more pronounced during hominin evolution.

Plants phenotypically adjust to environmental challenges, and the gaseous plant hormone ethylene modulates many of these growth adjustments. Ethylene can be involved in environmentally induced growth inhibition as well as growth stimulation. Still, ethylene has long been considered a growth inhibitory hormone. There is, however, accumulating evidence indicating that growth promotion is a common feature in ethylene responses. This is evident in environmental challenges, such as flooding and competition, where the resulting avoidance responses can help plants avoid adversity. To show how ethylene-mediated growth enhancement can facilitate plant performance under adverse conditions, we explored a number of these exam-ples. To escape adversity, plants can optimize growth and thereby tolerate abiotic stresses such as drought, and this response can also involve ethylene. In this article we indicate how opposing effects of ethylene on plant growth can be brought about, by discussing a unifying, biphasic ethylene response model. To understand the mechanistic basis for this multitude of ethylene-mediated growth responses, the involvement of ethylene in processes that control cell expansion is also reviewed.

Explaining sexual ornamentation in the limiting sex, usually females, requires information on the proximate background of ornaments and their consequences for sexual selection. Phenotypic variation within individuals has received little attention in either of these research directions. We used 6 years of data to examine the information content and potential role of white wing patch size in female collared flycatchers, Ficedula albicollis. Female wing patch size differed among years. Yearling females had smaller wing patches than older females. The negative effect of original patch size on intraindividual patch size change was stronger in yearling than in older birds, which may reflect an age-dependent trade-off. Change in wing patch size was strongly positively related to the summer North Atlantic Oscillation (NAO) index. Clutch size laid in the previous breeding season had a negative effect on patch size change, but only in high-NAO years. Thus, the immediate effect of poor climate during moult apparently overrode the more indirect influence of reproductive effort. Two sexually selected ornaments of mates were unrelated to female wing patch size at the population level, but intraindividual changes of female wing patch size significantly predicted differences in wing patch size between mates obtained in the 2 years. Our data suggest that significant mating advantages to more ornamented females may not be detected from population-level mating patterns. Research on potential female ornaments should also pay more attention to age-dependent phenotypic plasticity, the trade-off between current and future ornament size and the costs of reproduction to apparent future attractiveness.

To explore the potential evolutionary relevance of heritable epigenetic variation, the National Evolutionary Synthesis Center recently hosted a catalysis meeting that brought together molecular epigeneticists, experimental evolutionary ecologists, and theoretical population and quantitative geneticists working across a wide variety of systems. The group discussed the methods available to investigate epigenetic variation and epigenetic inheritance, and how to evaluate their importance for phenotypic evolution. We found that understanding the relevance of epigenetic effects in phenotypic evolution will require clearly delineating epigenetics within existing terminology and expanding research efforts into ecologically relevant circumstances across model and nonmodel organisms. In addition, a critical component of understanding epigenetics will be the development of new and current statistical approaches and expansion of quantitative and population genetic theory. Although the importance of heritable epigenetic
effects on evolution is still under discussion, investigating them in the context of a multidisciplinary approach could transform the field.

Erratum: In the Figure 9 color key, the labels for prunasin and RuBisCO were reversed. This error will be  corrected in the PDF and HTML versions of the article shortly
Abstract:  Cyanogenic glycosides (CNglcs) are bioactive plant products derived from amino acids. Structurally, these specialized plant compounds are characterized as α-hydroxynitriles (cyanohydrins) that are stabilized by glucosylation. In recent years, improved tools within analytical chemistry have greatly increased the number of known CNglcs by enabling the discovery of less abundant CNglcs formed by additional hydroxylation, glycosylation, and acylation reactions. Cyanogenesis—the release of toxic hydrogen cyanide from endogenous CNglcs—is an effective defense against generalist herbivores but less effective against fungal pathogens. In the course of evolution, CNglcs have acquired additional roles to improve plant plasticity, i.e., establishment, robustness, and viability in response to environmental challenges. CNglc concentration is usually higher in young plants, when nitrogen is in ready supply, or when growth is constrained by nonoptimal growth conditions. Efforts are under way to engineer CNglcs into some crops as a pest control measure, whereas in other crops efforts are directed toward their removal to improve food safety.Given that many food crops are cyanogenic, it is important to understand the molecular mechanisms regulating cyanogenesis so that the impact of future environmental challenges can be anticipated.

Cockatoos are the distinctive family Cacatuidae, a major lineage of the order of parrots (Psittaciformes) and distributed throughout the Australasian region of the world. However, the evolutionary history of cockatoos is not well understood. We investigated the phylogeny of cockatoos based on three mitochon- drial and three nuclear DNA genes obtained from 16 of 21 species of Cacatuidae. In addition, five novel mitochondrial genomes were used to estimate time of divergence and our estimates indicate Cacatuidae diverged from Psittacidae approximately 40.7 million years ago (95% CI 51.6–30.3 Ma) during the Eocene. Our data shows Cacatuidae began to diversify approximately 27.9 Ma (95% CI 38.1–18.3 Ma) during the Oligocene. The early to middle Miocene (20–10 Ma) was a significant period in the evolution of modern Australian environments and vegetation, in which a transformation from mainly mesic to xeric habitats (e.g., fire-adapted sclerophyll vegetation and grasslands) occurred. We hypothesize that this environmen- tal transformation was a driving force behind the diversification of cockatoos. A detailed multi-locus molecular phylogeny enabled us to resolve the phylogenetic placements of the Palm Cockatoo (Probosciger aterrimus), Galah (Eolophus roseicapillus), Gang-gang Cockatoo (Callocephalon fimbriatum) and Cockatiel (Nymphicus hollandicus), which have historically been difficult to place within Cacatuidae. When the molecular evidence is analysed in concert with morphology, it is clear that many of the cockatoo species’ diagnostic phenotypic traits such as plumage colour, body size, wing shape and bill morphology have evolved in parallel or convergently across lineages.

Primate socioecological studies have attempted to derive general frameworks using the average behavioural traits of species or genera to place them into categories. However, with the accumulation of primate studies, it is timely to place more emphasis on understanding within-species variation in social structure. In this review we have four objectives. First, we examine within-species variation in the potential determinants of social structure, including diet, demography, predation and infanticide, and document considerable variation. Second, we present case studies of within-species variation in social structure to illustrate the potential magnitude of this variation. For example, there are cases within a single interbreeding population where multi-male, uni-male, fission–fusion and monogamous groups are found. Third, by examining widespread primate lineages that occur in a variety of habitats, we note that there are differences in the magnitude of variation in social structures across different lineages and as a result we consider phylogenetic constraints on phenotypic variation in social structure. Finally, we reflect on the implications of extensive variation in social structure. We suggest that primate social structure will represent a combination of adaptation to present-day environment and phylogenetic inertia. To advance our understanding of the relative contribution of phylogeny versus ecology we propose two approaches. One approach is to compare groups in the same interbreeding population that inhabit different ecological conditions. Any differences that are found can be attributed to ecological differences, since phylogeny should not play a role within a single population. The second approach is to study distantly related species that have similar social structures to illustrate how similar ecological pressures might be operating to select for parallel social structures.

Tree leaves are interfaces between the whole organism and the environment. Leaves display a series of attributes that are linked to specific functions (functional leaf traits-FLT) and/or show responses to biotic and abiotic stress factors (stress response traits, SRT), which can be subdivided into: (a) morphological traits; (b) chemical traits; (c) physiological traits; (d) symptoms. The analysis of FLT is a useful tool for tree species and provenance phenotyping, due to the adaptation of trees to environmental stress. Additionally, FLT can be used as response factor in long term and large spatial scales surveys of forest conditions. Despite these potential benefits of leaf traits in the assessment of ecosystem health and functioning, leaf sampling in forests is time-consuming and costly, especially in forests with a complex vertical and horizontal structure and in remote forest areas. Once a foliar sample has been collected, many different analyses can be carried out; however, analyses should be technically simple and able to be performed within one day following the leaf collection (i.e., on fresh samples), or after air-drying the leaves themselves (analysis of dried specimens). This paper reports the results of leaf sampling and foliar analyses carried out in previous research projects and revises the current state-of-the-art. The leaf traits that are easily obtainable from leaf sampling are listed, together with the operational procedures necessary for their measurement, described in a standardized protocol. Their ecological and functional relevance is discussed in relation to their potential information (as indicators of climatic stress, drought, air and soil pollution, tree light-use and competition, plant nutritional status, health and general plant stress conditions). Finally, this review provides suggestions for the elaboration and reporting of data, and proposes some guidelines to improve the effectiveness of foliar analysis in the assessment of forest ecosystem health, properties and functioning.

Temperament describes the idea that individual behavioural differences are repeatable over time and across situations. This common phenomenon covers numerous traits, such as aggressiveness, avoidance of novelty, willingness to take risks, exploration, and sociality. The study of temperament is central to animal psychology, behavioural genetics, pharmacology, and animal husbandry, but relatively few studies have examined the ecology and evolution of temperament traits. This situation is surprising, given that temperament is likely to exert an important influence on many aspects of animal ecology and evolution, and that individual variation in temperament appears to be pervasive amongst animal species. Possible explanations for this neglect of temperament include a perceived irrelevance, an insufficient understanding of the link between temperament traits and fitness, and a lack of coherence in terminology with similar traits often given different names, or different traits given the same name. We propose that temperament can and should be studied within an evolutionary ecology framework and provide a terminology that could be used as a working tool for ecological studies of temperament. Our terminology includes five major temperament trait categories: shyness-boldness, explorationavoidance, activity, sociability and aggressiveness. This terminology does not make inferences regarding underlying dispositions or psychological processes, which may have restrained ecologists and evolutionary biologists from working on these traits. We present extensive literature reviews that demonstrate that temperament traits are heritable, and linked to fitness and to several other traits of importance to ecology and evolution. Furthermore, we describe ecologically relevant measurement methods and point to several ecological and evolutionary topics that would benefit from considering temperament, such as phenotypic plasticity, conservation biology, population sampling, and invasion biology.

Why do captive-reared fishes generally have lower fitness in natural environments than wild con- specifics, even when the hatchery fishes are derived from wild parents from the local population? A thorough understanding of this question is the key to design artificial rearing environments that optimize post-release performance, as well as to recognize the limitations of what can be achieved by modifying hatchery rearing methods. Fishes are generally very plastic in their development and through gene–environment interactions, epigenetic andmaternal effects their phenotypeswill develop differently depending on their rearing environment. This suggests that there is scope formodifying con- ventional rearing environments to better prepare fishes for release into the wild. The complexity of the natural environment is impossible tomimic in full-scale rearing facilities. So, in reality, the challenge is to identify key modifications of the artificial rearing environment that are practically and economically feasible and that efficiently promote development towards a more wild-like phenotype. Do such key modifications really exist? Here, attempts to use physical enrichment and density reduction to improve the performance of hatchery fishes are discussed and evaluated. These manipulations show potential to increase the fitness of hatchery fishes released into natural environments, but the success is strongly dependent on adequately adapting methods to species and life stage-specific conditions.

Organisms are niche constructors: they impact the environment and modify selective pressures that direct their own evolution as well as that of their non-conspecific fellows in ecological systems at various scales. The theoretical acknowledgement of niche construction has inspired many reflections about the active role of organisms in evolution, often proclaiming a revolutionary theoretical change. But if we look at formal models the claim is not yet justified. Ecologists have specified population-scale models of niche construction, but these cannot be adopted as evolutionary models: they don't incorporate heritable variation nor allow for directional selection and cumulative change. As evolutionists point out, these models are mere phenotype dynamics or population fluctuations with different possible outcomes - extinction or sustainability. Evolutionary models of niche construction, on the other hand, are not so revolutionary in their foundations, often being just classical population genetics provided with feedback loops between loci and selective pressures acting on them. The idea that variation among organisms boils down to genetic differences captured by gene frequencies dates back to the heart of the Modern Synthesis. But niche construction points directly to the world of physical and chemical interactions. This is the world where resource-impacting phenotypes are built through developmental processes, in turn subject and sensitive to the surrounding environment and the resources left over by previous generations. The produced phenotypes and their effects are hardly summarized by gene frequencies, yet evolutionary models need some kind of heritable variation and selection. The future challenge of evolutionary modeling beyond the Modern Synthesis is thus ecological, plastic variation that allows for inheritance with varying degrees and not-always-allelic mechanisms.

Chinook salmon, Oncorhynchus tshawytscha, from the Sacramento River, California, USA were introduced to New Zealand between 1901 and 1907, and colonized most of their present-day range within about 10 years. The New Zealand populations now vary in phenotypic traits typically used to differentiate salmon populations within their natural range: growth in freshwater and at sea, age at maturity, dates of return to fresh water and reproduction, morphology, and reproductive allocation. This paper reviews a large research program designed to determine the relative contributions of phenotypic plasticity and genetic adaptation to this variation, in an effort to understand the processes underlying the natural evolution of new populations. We found strong evidence of trait divergence between populations within at most 30 generations, particularly in freshwater growth rate, date of return, and reproductive output, with plausible adaptive bases for these differences. Importantly, we also demonstrated not only a genetic basis for post-release survival but higher survival, and hence fitness, of a population released from its established site compared to another population released from the same site. We conclude that divergence of salmon in different rivers probably resulted initially from phenotypic plasticity (e.g., habitat-specific growth rates, and effects of upriver migration on ovarian investment). Philopatry (homing to natal streams) combined with rapid evolution of distinct breeding periods to restrict gene flow, facilitating divergence in other traits. We also suggest that in addition to genetic divergence resulting from random founder effects, divergence may also arise during the very early stages of colonization when the original colonists are a non-random, pre-adapted subset of the source population. This 'favored founders effect' immediately improves the fitness of the new population. Overall, this research reveals the complex interplay of environmental and genetic controls over behavior, physiology and life history that characterize the early stages of population differentiation, a process that has taken place repeatedly during the history of salmon populations.

Aims The architecture of a plant depends on the nature and relative arrangement of each of its parts; it is, at any given time, the expression of an equilibrium between endogenous growth processes and exogenous constraints exerted by the environment. The aim of architectural analysis is, by means of observation and sometimes experimentation, to identify and understand these endogenous processes and to separate them from the plasticity of their expression resulting from external influences. † Scope Using the identification of several morphological criteria and considering the plant as a whole, from germination to death, architectural analysis is essentially a detailed, multilevel, comprehensive and dynamic approach to plant development. Despite their recent origin, architectural concepts and analysis methods provide a powerful tool for studying plant form and ontogeny. Completed by precise morphological observations and appropriated quantitative methods of analysis, recent researches in this field have greatly increased our understanding of plant structure and development and have led to the establishment of a real conceptual and methodological framework for plant form and structure analysis and representation. This paper is a summarized update of current knowledge on plant architecture and morphology; its implication and possible role in various aspects of modern plant biology is also discussed.

In 1858, two naturalists, Charles Darwin and Alfred Russel Wallace, independently proposed natural selection as the basic mechanism responsible for the origin of new phenotypic variants and, ultimately, new species. A large body of evidence for this hypothesis was published in Darwin's Origin of Species one year later, the appearance of which provoked other leading scientists like August Weismann to adopt and amplify Darwin's perspective. Weismann's neo-Darwinian theory of evolution was further elaborated, most notably in a series of books by Theodosius Dobzhansky, Ernst Mayr, Julian Huxley and others. In this article we first summarize the history of life on Earth and provide recent evidence demonstrating that Darwin's dilemma (the apparent missing Precambrian record of life) has been resolved. Next, the historical development and structure of the "modern synthesis" is described within the context of the following topics: paleobiology and rates of evolution, mass extinctions and species selection, macroevolution and punctuated equilibrium, sexual reproduction and recombination, sexual selection and altruism, endosymbiosis and eukaryotic cell evolution, evolutionary developmental biology, phenotypic plasticity, epigenetic inheritance and molecular evolution, experimental bacterial evolution, and computer simulations (in silico evolution of digital organisms). In addition, we discuss the expansion of the modern synthesis, embracing all branches of scientific disciplines. It is concluded that the basic tenets of the synthetic theory have survived, but in modified form. These sub-theories require continued elaboration, particularly in light of molecular biology, to answer openended questions concerning the mechanisms of evolution in all five kingdoms of life. Dedicated to Prof. Dr. Dr. hc mult. Ernst Mayr on the occasion of his 100th birthday U. Kutschera ( ) )

It is reported that the Prophet Mohamed (pbuh) said, (In a dream) I saw myself following a herd of black sheep. Then a group of white sheep came (and mixed with the black sheep) until they (the white sheep) became so many that the black sheep could no longer be seen in the herd of sheep." Abu Bakr, the companion of the Prophet (pbuh) and the interpreter of dreams, said, "Oh Messenger of Allah. As for the black sheep, they are the Arabs. They will accept Islam and become many. The white sheep are the non-Arab Persians, etc. They will accept Islam and become so many that the Arabs will not be noticed amongst them." The Prophet Mohamed (pbuh) then said that an angel had interpreted the dream the same way.

This article surveys and synthesizes dynamic systems models of development from biology, neuroscience, and psychology in order to propose an integrated account of growth, learning, and behavior. Key to this account is the concept of self-differentiation or symmetry-breaking. I argue that development can be understood as a cascade of symmetry-breaking events brought about by the ongoing interactions of multiple, nested, nonlinear dynamic systems whose self-organizing behaviors gradually alter their own anatomical conditions.

The discipline of biosemiotics applies semiotic terms to nonhuman organisms, even to those that lack neural system and brain. It views semiosis as the core property of life, rather than an advanced type of activity which appears at later stages of evolution when organisms became sufficiently complex. The origin of life was associated with the emergence of most primitive hereditary signs capable of carrying functions to descentent primordial agents. Accordingly, biological evolution is rooted in semiosis – a process of active interpretation by hereditary signs (both, genetic and epigenetic) in the context of other signs that come from the parts of the body and the environment. The biosemiotic concept of agency-driven evolution is opposed to neo-Darwinism that views evolution as a passive change of gene frequency via natural selection, drift, and other processes. The latter gene-centered approach is usually combined with genetic determinism and assumption that innovations are based solely on mutations. In contrast we consider mutations as disturbances that are creatively interpreted by cell subagents based on their experience, encoded genetically and epigenetically. Thus, mutation are not primary causes of adaptation, but being interpreted by subagents, they indirectly facilitate robustness, adaptive plasticity, and genetic assimilation. This reasoning resembles components of Lamarck’s theory. The genome may change passively and randomly, but its interpretation is active and guided by the logic of agent functions and embryo development. Emergence of new functions is based on the reinterpretation of the genome, when old tools, resources, and control algorithms are adopted for novel purposes. The biosemiotic approach to evolution can explain challenging questions, such as (i) emergence of interpretation capacity in primordial systems at the origin of life, (ii) remarkable consistency of phenotypic traits in the absence of genetic determinism, (iii) capacity of lineages to generate new solutions of living problems in critical conditions, (iv) the origin and nature of species, and (v) capacity to integrate into higher-level semiotic systems, such as colonies or super-organisms.

Contents: 1. Major steps towards the extension: Four women who changed the evolutionary scene. 2. The model of extended synthesis adds the independent role of plasticity. 3. Plasticity and interpretation. 4. Adaptive and neutral modifications. 5. Innovation and test. 6. Selection, adjustment and choice – illusionary and real meaning-making. 7. Inheritance of knowing. 8. Completely extended synthesis tends to be the semiotic theory of evolution. 9. Conclusion.

Abstract: The theory of organic evolution is incomplete until it can explain life’s meaning-making capacity and its role in the evolutionary processes, i.e. until semiosis is included. The extended synthesis theory of evolution has made a decisive step towards such an integrative theory, yet the explicit inclusion of semiotics of life is still to come. Here, we describe the steps made towards the semiotics-based theory of evolution, as the next stage after evo-devo and eco-evo-devo approaches. This includes demonstration of independent roles that natural selection, plastic adjustment, and interpretative choice have in adaptive evolution, and the distinction between adaptive and neutral modifications in genetic, plastic and interpretative mechanisms. Real meaning-making takes place only due to organism’s interpretative processes. It should be complemented with a description of the ways by which knowledge (defined as products of semiotic learning), or rather the constraints of semiosis, can be inherited. This will complete the inclusion of semiosis into the extended mechanism of evolution.

Honeybee workers are essentially sterile female helpers that make up the majority of individuals in a colony. Workers display a marked change in physiology when they transition from in-nest tasks to foraging. Recent technological advances have made it possible to unravel the metabolic modifications associated with this transition. Previous studies have revealed extensive remodeling of brain, thorax, and hypopharyngeal gland biochemistry. However, data on changes in the abdomen is scarce. To narrow this gap we investigated the proteomic composition of abdominal tissue in the days typically preceding the onset of foraging in honeybee workers. In order to get a broader representation of possible protein dynamics, we used workers of two genotypes with differences in the age at which they initiate foraging. This approach was combined with RNA interference-mediated downregulation of an insulin/insulin-like signaling component that is central to foraging behavior, the insulin receptor substrate (irs), and with measurements of glucose and lipid levels. Our data provide new insight into the molecular underpinnings of phenotypic plasticity in the honeybee, invoke parallels with vertebrate metabolism, and support an integrated and irs-dependent association of carbohydrate and lipid metabolism with the transition from in-nest tasks to foraging.

"The consensus view in mirror neuron research is that mirror neurons comprise a uniform, stable execution–observation matching system. In this opinion article, we argue that, in light of recent evidence, this is at best an incomplete and oversimplified view of mirror neurons, where activity is actually variable and more plastic than previously theorized. We propose an epigenetic account for understanding developmental changes in sensorimotor systems, including variations in mirror neuron activity. Although associative and genetic accounts fail to consider the complexity of genetic and nongenetic interactions, we propose a new evolutionary developmental biology (evo-devo) perspective, which predicts that environmental differences early in development, or through sensorimotor training, should produce variations in mirror neuron response patterns, tuning them to the social environment."

In this chapter, I analyze how the effort to bring together " nature " and " nurture " has put forward " plasticity " as a key concept in biology. While the notion of plasticity appeared in the field of genetics in the early 20 th century as a solution to the debate between " nature " and " nurture " – the notion of plasticity proved a key concept in articulating those genes and environment –, in social science the opposition seems to persist (probably because the meaning of plasticity itself has not remained stable or uncontroversial among the different fields of biology). In order to understand the issues raised by the nature-nurture debate, it therefore appears necessary to provide a comprehensive view of the history of plasticity within the debate.

The relative contribution of genetic and environmental influences to the US black-white disparity in cardiovascular disease (CVD) is hotly debated within the public health, anthropology, and medical communities. In this article, we review evidence for developmental and epigenetic pathways linking early life environments with CVD, and critically evaluate their possible role in the origins of these racial health disparities. African Americans not only suffer from a disproportionate burden of CVD relative to whites, but also have higher rates of the perinatal health disparities now known to be the antecedents of these conditions. There is extensive evidence for a social origin to prematurity and low birth weight in African Americans, reflecting pathways such as the effects of discrimination on maternal stress physiology. In light of the inverse relationship between birth weight and adult CVD, there is now a strong rationale to consider developmental and epigenetic mechanisms as links between early life environmental factors like maternal stress during pregnancy and adult race-based health disparities in diseases like hypertension, diabetes, stroke, and coronary heart disease. The model outlined here builds upon social constructivist perspectives to highlight an important set of mechanisms by which social influences can become embodied, having durable and even transgenerational influences on the most pressing US health disparities. We conclude that environmentally responsive phenotypic plasticity, in combination with the better-studied acute and chronic effects of social-environmental exposures, provides a more parsimonious explanation than genetics for the persistence of CVD disparities between members of socially imposed racial categories. Am. J. Hum. Biol. 00:00-00, 2008.

The hypothalamo-pituitary-adrenal (HPA) axis is the critical mediator of the vertebrate stress response system, responding to environmental stressors by maintaining internal homeostasis and coupling the needs of the body to the wants of the mind. The HPA axis has numerous complex drivers and highly flexible operating characterisitics. Major drivers include two circadian drivers, two extra-hypothalamic networks controlling top-down (psychogenic) and bottom-up (systemic) threats, and two intra-hypothalamic networks coordinating behavioral, autonomic, and neuroendocrine outflows. These various networks jointly and flexibly control HPA axis output of periodic (oscillatory) functions and a range of adventitious systemic or psychological threats, including predictable daily cycles of energy flow, actual metabolic deficits over many time scales, www.elsevier.com/locate/pneurobio

Relative gut length, Zihler's index, and relative gut mass were measured in four species of prickleback fishes and the effects of ontogeny, diet, and phylogeny on these gut dimensions were determined. Of the four species, Cebidichthys violaceus and Xiphister mucosus shift to herbivory with growth (>45 mm SL), whereas X. atropurpureus and Anoplarchus purpurescens remain carnivores. A. purpurescens belongs to a carnivorous clade, and the three other species belong to an adjacent, herbivorous clade. Gut dimensions were compared in three feeding categories of the four species: (1) small, wild-caught juveniles representing the carnivorous condition before two species shift to herbivory; (2) larger, wild-caught juveniles representing the natural diet condition of the two carnivores and the two species that have shifted to herbivory; and (3) larger, laboratoryraised juveniles produced by feeding a high-protein artificial diet to small juveniles until they have reached the size of the larger, wild-caught juveniles. Comparisons of gut dimensions in categories (1) versus (2) tested for an ontogenetic effect, in (2) versus (3) for a dietary effect, and within each category for a phylogenetic effect. C. violaceus and X. mucosus increased gut dimensions with increase in body size and did not change ontogenetic trajectory in gut dimensions on the high-protein artificial diet, suggesting that they are genetically programmed to develop relatively large guts associated with herbivory. X. atropurpureus increased its gut dimensions with increase in size similar to its sister taxon, X. mucosus, suggesting a phylogenetic influence, but decreased gut dimensions on the high-protein artificial diet, suggesting phenotypic plasticity. Nevertheless, X. atropurpureus displayed a larger gut than A. purpurescens, further evidence that it evolved in an herbivorous clade. A. purpurescens possessed a relatively small gut that was little affected by ontogeny or diet. Ontogeny and phylogeny more than diet appear to influence gut dimensions in the four species, thus favoring genetic adaptation over phenotypic plasticity as the major force acting on digestive system features in the two prickleback clades.

Ocean acidification (OA), a consequence of anthropogenic carbon dioxide emissions, poses a serious threat to marine organisms in tropical, openocean, coastal, deep-sea, and high-latitude sea ecosystems. The diversity of taxonomic groups that precipitate calcium carbonate from seawater are at particularly high risk. Here we review the rapidly expanding literature concerning the biological and ecological impacts of OA on calcification, using a cross-scale, process-oriented approach. In comparison to calcification, we find that areas such as fertilization, early life-history stages, and interaction with synergistic stressors are understudied. Although understanding the long-term consequences of OA are critical, available studies are largely shortterm experiments that do not allow for tests of long-term acclimatization or adaptation. Future research on the phenotypic plasticity of contemporary organisms and interpretations of performance in the context of current environmental heterogeneity of pCO 2 will greatly aid in our understanding of how organisms will respond to OA in the future. Calcium carbonate (CaCO 3 ): the main component of the shells and skeletons of marine organisms, occurring in the form of aragonite, calcite, and high-Mg calcite. CO 3 2− : carbonate ion 128 Hofmann et al. SUMMARY POINTS 1. Although OA is occurring on a global scale, coral reefs, the open ocean, the deep sea, coastal oceans, and high-latitude seas differ in their vulnerability to OA. The knowledge base regarding responses to OA for taxa in each ecosystem varies, with a distinct data deficit on calcifying organisms in the deep sea and high-latitude seas. 2. Studies that document the effect of OA conditions on calcification by key calcifiers in each ecosystem generally show a deleterious impact, although, with greater taxonomic coverage, there is an emerging variation in response to OA. Numerous other physiological processes are understudied. Notably, more studies that integrate the response to OA across life-history transitions are needed, as are studies that further explore the metabolic costs of function under OA conditions.