Evolutionary theory predicts an interactive process whereby spatiotemporal environmental heterogeneity will maintain genetic variation, while genetic and phenotypic diversity will buffer populations against stress and allow for fast adaptive evolution in rapidly changing environments. Here, we study color polymorphism patterns in pygmy grasshoppers (Tetrix subulata) and show that the frequency of the melanistic (black) color variant was higher in areas that had been ravaged by fires the previous year than in nonburned habitats, that, in burned areas, the frequency of melanistic grasshoppers dropped from ca. 50% one year after a fire to 30% after four years, and that the variation in frequencies of melanistic individuals among and within populations was genetically based on and represented evolutionary modifications. Dark coloration may confer a selective benefit mediated by enhanced camouflage in recently fire-ravaged areas characterized by blackened visual backgrounds before vegetation has recovered. These findings provide rare evidence for unusually large, extremely rapid adaptive contemporary evolution in replicated natural populations in response to divergent and fluctuating selection associated with spatiotemporal environmental changes.

Biological diversity is threatened by exploitation, fragmentation of natural habitats, pollution, climatechange, and anthropogenic spread of species. The question of how among-individual variation influencesthe performance of populations and species is a poorly explored but currently growing field of research.Here, we review 31 experimental and 14 comparative studies and first investigate whether there is empiricalsupport for the propositions that higher levels of among-individual phenotypic and genetic variationpromote the ecological and evolutionary success of populations and species in the face of environmentalchange. Next, we examine whether and how the effect of diversity depends on environmental conditions.Finally, we explore whether the relationship linking population fitness to diversity is typically linear,asymptotic, or whether the benefits peak at intermediate diversity. The reviewed studies provide strong,almost invariable, evidence that more variable populations are less vulnerable to environmental changes,show decreased fluctuations in population size, have superior establishment success, larger distributionranges, and are less extinction prone, compared with less variable populations or species. Given theoverwhelming evidence that variation promotes population performance, it is important to identifyconditions when increased variation does not have the theoretically expected effect, a question ofconsiderable importance in biodiversity management, where there are many other practical constraints. Wefind that experimental outcomes generally support the notion that genetic and phenotypic variation is ofgreater importance under more stressful than under benign conditions. Finally, population performanceincreased linearly with increasing diversity in the majority (10 of 12) of manipulation studies that includedfour or more diversity levels; only two experiments detected curvilinear relationships.

Environmental changes currently pose severe threats to biodiversity, and reintroductions and translocations are increasingly used to protect declining populations and species from extinction. Theory predicts that establishment success should be higher for more variable groups of dissimilar individuals. To test this ‘diversity promotes establishment’ hypothesis, we introduced colour polymorphic pygmy grasshoppers (Tetrix subulata) to different sites in the wild. The number of descendants found at the release sites the subsequent year increased with increasing number of colour morphs in the founder group, and variation in founder groups also positively affected colour morph diversity in the established populations. Since colour morphs differ in morphology, physiology, behaviour, reproductive life history and types of niche used, these findings demonstrate that variation among individuals in functionally important traits promotes establishment success under natural conditions, and further indicate that founder diversity may contribute to evolutionary rescue and increased population persistence.

Gene flow is often regarded a random process that homogenizes differencesbetween populations and constrains local adaptation. However, the matching habitat choicehypothesis posits that individuals actively choose those microhabitats that best match theirspecific phenotype to maximize fitness. Dispersal (and possibly gene flow) may thus bedirected. Many studies report associations between habitats and phenotypes, but they mayreflect selection, plasticity or adaptation rather than matching choice. Here, we test twopredictions from the matching habitat choice hypothesis by manipulating the dorsal colourof Tetrix subulata, a pygmy grasshopper. (1) Is microhabitat choice flexible such thatdifferently manipulated phenotypes distribute themselves differently in a microclimaticand solar radiation mosaic? (2) If they do, are their fitness prospects higher in the morepreferred microhabitat? We find that individuals painted white or black do distributethemselves differently, with black individuals residing in habitats with less radiation, onaverage, than white individuals, demonstrating that microhabitat choices are plastic. Furthermore,white females had more hatchlings than black ones in the increased radiationtreatment, and this was mainly due to increased mortality of black females under increasedradiation. These findings provide rare experimental evidence in line with predictions fromthe matching habitat choice hypothesis.

Många elever har svårigheter i att skapa mening kring naturvetenskapliga koncept. Tidigare studier inom biologiämnet visar att elever har svårt för att beskriva och tolka hur näringsvävar och andra komplexa begrepp hänger samman. Undervisning och lärande inom naturvetenskapliga områden är beroende av en stor mängd representationer som illustrerar fenomen som är för små, stora, abstrakta eller komplexa för att kunna beskrivas enbart med ord. En förutsättning för att elever ska kunna skapa mening kring naturvetenskapliga begrepp är dels att de kan tolka de representationer som används i undervisningen, dels att de aktivt använder representationer. De möjligheter och utmaningar som elever upplever i sitt meningsskapande i samband med ett eget konstruerande av representationer har rönt alltmer intresse; dock saknas studier som specifikt rör ekologiundervisningen. Syftet med denna studie är att identifiera elevers olika syn på komplexa ekologiska koncept och illustrera på vilket sätt eleverna försöker kombinera dessa för en större helhetsförståelse. Insamlad data består av bilder som elever skapat under ett grupparbete och dessa tolkas ur ett socialsemiotiskt perspektiv. Resultaten indikerar att eleverna fokuserar på representationernas ytliga egenskaper, snarare än den underliggande strukturen, samt att strukturen och vetenskapligheten i elevers visuella beskrivningar av ekologiska koncept skiljer sig åt. Eleverna uppvisar svårigheter när de försöker kombinera faktorer kopplade till olika kretslopp. Vidare visar resultaten att eleverna behöver stöd i att skapa en helhetsbild av ekologiska processer och att analys av elevers representationer kan användas för att identifiera elevers svårigheter. Detta kan möjliggöra ett djupare och mer vetenskapligt resonerande i det naturvetenskapliga klassrummet.

Teaching and learning in biology and other science disciplines are highly dependent on representations illustrating phenomena too small, big, abstract or complex to be described by words only. Many students have difficulties learning scientific concepts and lack an idea of “the bigger picture”. Earlier research in biology implicate that students have difficulties describing and interpreting food webs and other concepts concerning ecological systems. One area that is attaining a greater interest is the learning possibilities when students’ actively construct representations. Very little attention has, however, been paid to this line of research in the area of ecology. Accordingly, the purpose of this study was to identify students' different views on complex ecological concepts and illustrate the manners by which students attempt to link them together for a more holistic understanding. Data consists of students’ drawings and interviews, that together can give a better understanding of how students take advantage of actively constructing representations. Results indicate that students’ interpretations and ideas regarding ecological concepts differ widely. They describe biological concepts with different levels of abstraction and show difficulties combining abiotic and biotic factors in biological cycles. The results give further insights into how explicit focus on ecological process and concepts can be used to scaffold students’ construction of representations. Furthermore, teachers can employ such representations for formative assessment. A better understanding of how students' active construction of representations influences their opportunities for meaning making will increase the opportunities for a deeper, more scientific, reasoning in the science classroom.

Consequences of within population variation have recently attracted an increased interest in evolutionary ecology research. Theoretical models suggest important population-level consequences, but many of these predictions still remain to be tested. These issues are important for a deepened understanding of population performances and persistence, especially in a world characterized by rapid fragmentation of natural habitats and other environmental changes.

I review theoretical models of consequences from intra population genetic and phenotypic variation. I find that more variable populations are predicted to be characterized by broader resource use, reduced intraspecific competition, reduced vulnerability to environmental changes, more stable population dynamics, higher invasive potential, enhanced colonization and establishment success, larger distribution ranges, higher evolvability, higher productivity, faster population growth rate, decreased extinction risk, and higher speciation rate, compared with less variable populations.

To test some of these predictions I performed experiments and compared how different degree of colour polymorphism influences predation risk and establishment success in small groups. My comparisons of predation risk in mono- and polymorphic artificial prey populations showed that the risk of being eaten by birds does not only depend on the coloration of the individual prey item itself, but also on the coloration of the other members of the group. Two experiments on establishment success in small founder groups of

Tetrix subulata pygmy grasshoppers with different degree of colour morph diversity show that establishment success increases with higher degree of diversity, both under controlled conditions in outdoor enclosures and in the wild. These findings may be important for re-stocking of declining populations or re-introductions of locally extinct populations in conservation biology projects.

I report on remarkably rapid evolutionary shifts in colour morph frequencies in response to the changed environmental conditions in replicated natural populations of pygmy grasshoppers in fire ravaged areas. This finding

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illustrates the high adaptive potential in a polymorphic species, and indicates the importance of preserved within-species diversity for evolutionary rescue.

Finally, I review if theoretical predictions are supported by other published empirical tests and find strong support for the predictions that more variable groups benefit from reduced vulnerability to environmental changes, reduced population fluctuations and extinction risk, larger distribution ranges, and higher colonization or establishment success.

In conclusion, my thesis illustrates how within-population variation influences ecological and evolutionary performances of populations both in the short and long term. As such, it emphasizes the need for conservation of biodiversity also within populations.

Rapporten redovisar en undervisningsmodell i en biologikurs för lärarstu-denter. Syftet var att höja studentaktiviteten genom att låta studenter reflek-tera över och gemensamt bearbeta ämnesinnehållet. Alla föreläsningarspelades in och avslutades med ett antal reflektionsfrågor som studenternadiskuterade på den digitala kurssidan. Interaktionen mellan lärare och stu-denter under föreläsningar byttes ut mot diskussioner under schemalagdareflektionsseminarier. Varje seminarium resulterade i ett protokoll somläraren skrev och som sedan lades ut på kurssidan som en av flera resurserför instudering till avslutande tentamen. Utvärderingen visar att modellen uppskattats av såväl lärare som studenter.

Att undervisa om evolution och förutsättningarna för evolutionär anpassningi skolan är mycket viktigt och leder bland annat till en förståelse för varför vibehöver värna om biologisk mångfald. Detta menar Lena Wennersten, tidigareverksam som mellanstadielärare men numera som forskare och lärarutbildarevid Linnéuniversitet i Kalmar. Här berättar hon om egna experimentför att testa vikten av genetisk variation inom arter.

That colour polymorphism may protect prey populations from predation is an old but rarely tested hypothesis. We examine whether colour polymorphic populations of prey exposed to avian predators in an ecologically valid visual context were exposed to increased extinction risk compared with monomorphic populations. We made 2976 artificial pastry prey, resembling Lepidoptera larvae, in four different colours and presented them in 124 monomorphic and 124 tetramorphic populations on tree trunks and branches such that they would be exposed to predation by free-living birds, and monitored their 'survival'. Among monomorphic populations, there was a significant effect of prey coloration on survival, confirming that coloration influenced susceptibility to visually oriented predators. Survival of polymorphic populations was inferior to that of monomorphic green populations, but did not differ significantly from monomorphic brown, yellow or red populations. Differences in survival within polymorphic populations paralleled those seen among monomorphic populations; the red morph most frequently went extinct first and the green morph most frequently survived the longest. Our findings do not support the traditional protective polymorphism hypothesis and are in conflict with those of earlier studies. As a possible explanation to our findings, we offer a competing 'giveaway cue' hypothesis: that polymorphic populations may include one morph that attracts the attention of predators and that polymorphic populations therefore may suffer increased predation compared with some monomorphic populations.

The consequences of among-individual phenotypic variation for the performance and ecological success of populations and species has attracted growing interest in recent years. Earlier reviews of this field typically address the consequences for population processes of one specific source of variation (plasticity or polymorphism), or consider one specific aspect of population performance, such as rate of speciation. Here we take a broader approach and study earlier reviews in order to summarize and compare predictions regarding several population-level consequences of phenotypic variation stemming from genetic polymorphism, developmental plasticity or randomized phenotype switching. Unravelling cause-dependent consequences of variation may increase our ability to understand the ecological dynamics of natural populations and communities, develop more informed management plans for protection of biodiversity, suggest possible routes to increased productivity and yield in natural and managed biological systems, and resolve inconsistencies in patterns and results seen in studies of different model systems. We find an overall agreement regarding the effects of higher levels of phenotypic variation generated by different sources, but also some differences between fine-grained and coarse-grained environments, modular and unitary organisms, mobile and sessile organisms, and between flexible and fixed traits. We propose ways to test the predictions and identify issues where current knowledge is limited and future lines of investigation promise to provide important novel insights.

Large founder groups and habitat match have been shown to increase the establishment success of reintroduced populations. Theory posits that the diversity of founder groups should also be important, but this has rarely been investigated. Here, experimental introductions of color-polymorphic Tetrix subulata pygmy grasshoppers into outdoor enclosures were used to test whether higher phenotypic diversity promotes establishment success. We show that the number of individuals present one year after introduction increases with color morph diversity in founder groups. Variance in establishment success did not decrease with increasing founder diversity, arguing against an important contribution of sampling effects or evolutionary rescue. Color morphs in T. subulata covary with a suite of other functionally important traits and utilize different resources. The higher establishment success in more diverse founder groups may therefore result, in part, from niche complementarity. Variation in establishment among groups was not associated with differences among source populations in reproductive capacities.

The matching habitat choice hypothesis posits that individuals actively choose those microhabitats that best match their specificphenotype to maximize fitness. Despite the profound implications, matching habitat choice has not been unequivocally demonstrated. Weconducted two experiments to examine the impact of pigmentation pattern in the color polymorphic pygmy grasshopper Tetrix subulata onhabitat choice in a laboratory thermal mosaic arena. We found no behavioral differences in the thermal mosaic among pygmy grasshoppersbelonging to either pale, intermediate or dark natural color morphs. However, after manipulating the grasshoppers’ phenotype, the utilizationthrough time of warmer and colder parts of the arena was different for black-painted and white-painted individuals. White-paintedindividuals used warmer parts of the arena, at least during the initial stage of the experiment. We conclude that microhabitat choicerepresents a form of behavioural plasticity. Thus, even if the choice itself is flexible and not genetically determined, it can still lead to spatialgenetic structure in the population because the phenotypes themselves may be genetically mediated

UNESCO has identified education for sustainable development (ESD) as a key factor in the achievement of sustainable development goals (SDGs). Education is important in developing awareness of how to preserve natural ecosystems and promote the uptake of renewable energy sources. Ecology education in primary school aims to give students a scientific foundation to further their education in biology and develop environmentally literate citizens who will protect, restore and promote the sustainable use of natural ecosystems. This early education includes awareness of how human welfare depends on functional ecosystems to provide food, clean water and oxygen. However, previous studies have shown that young students face serious challenges when constructing a holistic view of complex ecological relationships. In this study, we interpret students’ written texts and drawings when, in small groups, they were asked collectively to describe necessary functions in an ecosystem, as a final task after a series of lessons on ecology. By focusing on students’ expressed ideas on the availability of energy and matter in the ecosystem, we construe four models. The students in our study propose, firstly, that energy flows or can circulate, and secondly, that matter circulates, is provided by the sun, or is created anew. Moreover, the students often express fragmented processes, combined in different ways. According to our results, we propose aspects that can inform the design of primary school teaching of ecology for sustainable development.