Since the discoveries of vertebrate bioapatite’s ability to record oxygen isotopecomposition of ambient seawater were made (Kolodny, 1983), oxygen isotopes have beenwidely used as a climatic and oceanographic proxy. The δ18OP aquatic vertebrate apatite isa function of the δ18Ow value of the ambient water, yet “vital effects” on the δ18OP compositionhave been reported previously (Venneman et al., 2013). I have analysed δ18O compositionin the teeth of six extant shark and ray (chondrichthyan) species from the tropical ocean tankof the Blackpool Sea Life Center, UK. The teeth were naturally shed and collected from thetank substrate.Preparation of samples was performed in the Laboratory of Isotope Geology at the NaturalHistory Museum of Stockholm (Sweden), and the δ18O was measured at the NordSIM facility,using secondary ionization mass spectrometry (SIMS) by a high precision and high spatialresolutionCAMECA IMS 1280 ion microprobe.Data treatment was followed by statistical analysis. Results show significant δ18O differencesat inter-tissue level. I could also illustrate the impact of organics-pretreatment on the finalδ18O values, with the outcome of one more favourable pretreatment for SIMS analysis. Intertaxonvariability was observed, without much statistical confidence, but I hypothesize that itmay be due to the difference in tissue crystallization and organic quantity between species.

Haploid selection in animal sperm is a somewhat controversial topic, but recentevidence might shed experimental light on the matter. This thesis investigates thepossibility to detect any genetic selection in an artificial setting for zebrafish spermfrom a single individual. I analyse pooled data acquired from whole-genomesequencing for two distinct groups of short- and long-lived sperm, trying to identifyshifts in allele frequencies. I augment this by designing an accurate computersimulation of selection, that manipulates selection strength and takes biologicalaspects like linkage and sequence coverage into account. This allows large scaletesting and the generation of null distributions for any test metric. The mainconclusion is that selection has to be extremely strong to be detectable unless onewould explicitly account for genetic linkage, as opposed to the straightforwardper-marker approaches that formed the initial basis for our analyses.

Syftet med studien är att undersöka om inslag av drama i undervisningen kan användas som metod för att gynna elevers kunskapsutveckling inom evolutionsteorin, i grundskolans årskurs 4–6. Studien genomfördes i årskurs 5 på en kommunal skola i Mellansverige. Deltagarna som med vårdnadshavares samtycke deltog i studien, var till antalet 29 elever. I undersökningen samt i efterföljande analys användes kvasi-experimentell metod. Datainsamlingen bestod av summativa för-och eftertest där deltagarna har fått besvara frågor inom evolutionsteorin.Studien visar att drama som metod för inlärning av evolutionsteorin kan ge elever ökad kunskap inom området. Dessutom visar studien att flickor utvecklar sina kunskaper inom evolutionsteorin oavsett undervisningsmetod.Slutsatsen som kan dras av denna studie är att drama som metod i undervisning har påverkan på elevernas kunskapsutveckling, men behöver i större omfattning undersökas för att kunna generaliseras. Drama som metod bör ändock beaktas av lärare som ett verktyg i den pedagogiska planeringen

Procreation is often viewed as a joint undertaking where both parties depend on, and thus care about, the reproductive success of the other. This is however not always the case. Sexual antagonism occurs when males and females have different strategies for maximizing their fitness, leading to a “battle between the sexes”. Intralocus sexual conflict, IASC, involves sexual antagonism between different alleles at a specific locus, alleles that have opposite effects between the sexes. One potentially sexually antagonistic gene is Ugt36E1, a gene involved in the catalyzation of a conjugation reaction between different sugars from the donor uridine diphosphate (UDP) to many small, fat-soluble, often toxic exogenous or endogenous molecules. This makes them water soluble, after which they can be transported to various organs for elimination. The gene is thus very important for detoxification and for maintaining the homeostasis of the body’s cells. The purpose of the study is to investigate whether changes in the gene Ugt36E1 affect the fitness of female fruit flies in the form of an increased/decreased number of offspring. To accomplish this, female flies that had been modified using CRISPR/Cas9 to obtain two alternative alleles of the Ugt36E1 gene were collected and allowed to mate with wild-type males. The number of eggs and live offspring of the females were thereafter counted and analyzed. The study could not find a significant difference in the number of offspring between the alleles, which does not line up with previous studies. The gene is hypothesized to be important for both detoxification and homeostasis within the individual regardless of gender, and changes to this gene could therefore be thought to be harmful to both males and females, something that does not seem to agree with this study. Females also laid fewer eggs than expected across both groups. This could be the result of natural variation, but it could also indicate that something during the experiment affected them in a way that reduced their fecundity. Because of the results, and because the study was focused solely on the female side of the conflict, additional testing to further investigate the gene’s effect on the fitness of both genders is recommended. / Fortplantning ses ofta som ett gemensamt åtagande där båda parter är beroende av, och därför bryr sig om, den andras reproduktiva framgång. Detta är dock inte alltid fallet. Sexuell antagonism uppstår när hanar och honor har olika strategier för att maximera sin kondition, vilket leder till en "kamp mellan könen". Intralocus sexual conflict, IASC, innebär sexuell antagonism mellan olika alleler på ett specifikt lokus, alleler som har motsatta effekter mellan könen. En potentiellt sexuellt antagonistisk gen är Ugt36E1, en gen involverad i katalyseringen av en konjugationsreaktion mellan olika sockerarter från donatorn uridindifosfat (UDP) till många små, fettlösliga, ofta toxiska exogena eller endogena molekyler. Detta gör dem vattenlösliga, varefter de kan transporteras till olika organ för eliminering. Genen är alltså mycket viktig för avgiftning och för att upprätthålla homeostasen i kroppens celler. Syftet med studien är att undersöka om förändringar i genen Ugt36E1 påverkar konditionen hos fruktflugor i form av ett ökat/minskat antal avkommor. För att åstadkomma detta samlades bananflugehonor som hade modifierats med CRISPR/Cas9 för att erhålla två alternativa alleler av Ugt36E1-genen och fick para sig med hanar av vildtyp. Antalet ägg och levande avkommor från honorna räknades därefter och analyserades. Studien kunde inte hitta någon signifikant skillnad i antalet avkommor mellan allelerna, vilket inte stämmer överens med tidigare studier. Genen antas vara viktig för både avgiftning och homeostas inom individen oavsett kön, och förändringar av denna gen kan därför tänkas vara skadliga för både hanar och honor, något som inte verkar stämma överens med denna studie. Honor lade också färre ägg än förväntat i båda grupperna. Detta kan vara resultatet av naturlig variation, men det kan också tyda på att något under experimentet påverkade dem på ett sätt som minskade deras fruktsamhet. På grund av resultaten, och eftersom studien enbart fokuserade på den kvinnliga sidan av konflikten, rekommenderas ytterligare tester för att ytterligare undersöka genens effekt på konditionen hos båda könen.

Ephedra (Gnetales) is a gymnosperm genus with a long evolutionary history; the first dispersed pollen grains with affinity to the group are known already from the Permian. This thesis focuses on the evolutionary history of the group and different aspects of its pollination mechanisms. Despite the limited number of extant species of the genus (50-60), and a low morphological and genetic divergence among species, there is variation in pollination syndrome in the genus. The prevailing state in Ephedra, and most gymnosperms, is wind pollination. It is therefore surprising that one species, E. foeminea, is insect-pollinated. Together with co-workers I documented the pollination syndromes of E. foeminea and a sympatric species, E. distachya, based on long term field experiments in north-eastern Greece and aerodynamic investigations and calculations. Placing the results into an evolutionary framework reveals that the insect-pollinated species E. foeminea is sister to the remaining (mostly wind-pollinated) genus, and indicates that insect pollination is the ancestral state in the Gnetales. During the course of evolution of the group there has been a shift to wind pollination, which may have played a crucial role for the diversification of the crown group in the Paleogene. Pollination biology is often correlated with the morphology of the pollen such that pollen grains of anemophilous plants are small with a smooth surface, whereas pollen grains of entomophilous plants are larger with an ornamented surface and a covering of pollenkitt. The pollen morphology of Ephedra can be broadly divided into two types: an ancestral type with an unbranched pseudosulcus between each pair of plicae, and a derived type with a branched pseudosulcus between each pair of plicae. Further, the pollen morphology and ultrastructure of the pollen wall in Ephedra are to some degree correlated with the pollination syndrome and capability of long distance dispersal. Pollen of E. foeminea has a denser ultrastructure, as a result a higher settling velocity and is therefore capable of flying shorter distances than does pollen of the anemophilous E. distachya, and other investigated anemophilous species that show a more spacious ultrastructure of the pollen grain. These results can be useful in the reconstruction of the pollination mechanism of extinct taxa of the Ephedra-lineage in the future.

Norway spruce (Picea abies (L.) Karst.) together with the sister species Siberian spruce (P. obovata Ledeb.) form a vast continuous distribution over Eurasia. The present distribution of P. abies in Europe was formed recently, after the last glacial maximum. Theories about the colonization routes and history of this species differ depending on the datasets examined to date. This thesis aims to investigate the genetic structure and diversity of P. abies and establish its glacial refugia and postglacial migration. A range-wide sampling was performed of both P. abies and P. obovata, and a genotyping-by-sequencing approach was used to obtain whole-genome single nucleotide polymorphism (SNP) data. Two major genetic lineages of P. abies were found; northern and central Europe. The northern lineage was further divided into a Scandinavian and a north-east European cluster; the Scandinavian cluster being more closely related to P. obovata and the north-east European cluster to the central European lineage. Introgression from P. obovata was detected far into northern Fennoscandia. The central European lineage was divided into an Alpine and a Carpathian cluster, originating from different glacial refugia. Genetic diversity was higher in the northern part of the range, which can be attributed to the relatively large refugium that recolonized this area, as well as introgression from P. obovata. Genetic diversity was also somewhat elevated where the two central European clusters meet, as is expected in areas where two previously isolated lineages admix. This study is the first range-wide investigation of P. abies using whole-genome SNP information, and shows how the genetic structure of the species has been shaped by the last glacial maximum and postglacial recolonization.

Seasonal long-distance bird migration between wintering and breeding grounds is oneof the most remarkable phenomena in the history of life on earth. Migration strategies androutes vary greatly. Some birds migrate in social groups whilst others migrate alone at night,some cross few hundreds of km whilst others cover thousands of km. Avian migration has beenstudied extensively nevertheless numerous important questions remain unanswered. This studyaims to contribute to the understanding of the genetic basis of the innate migratory program ofa common songbird.From results of classical crossbreeding and orientation experiments with captiveblackcaps (Sylvia atricapilla) we can be sure that songbird migration directions as well asdurations are traits that are being inherited genetically and most likely have a multi-locusgenetic architecture. The chosen model species for my project is the willow warbler(Phylloscopus trochilus), one of the most common leaf warblers in the Palearctic. The willowwarbler has a continuous breeding distribution from the coast of the Atlantic to the coast ofPacific. They overwinter in sub-Saharan Africa. Three subspecies have been recognized: P. t.trochilus (breeding in central/western Europe and migrating SSW to western Africa), P. t.acredula (breeding in northern and eastern Europe, migrating SSE to east and south Africa)and P. t. yakutensis (breeding east of Ural Mountains, presumably migrating to SouthernAfrica). Morphological differences across the willow warbler subspecies are subtle and it has been previously shown that genome wide FST is close to zero. The low level of neutral back-ground divergence offers a good system for studying the genetics of passerine migration. This report contributes with novel data on phenotypes and genotypes of the subspecies yakutensisstudied at Chaun river delta, at the very eastern range limit of the species. As a proxy for thewintering location of yakutensis I used C and N stable isotope signatures from winter grownfeathers and inferred wintering range to be in Southern Africa. I genotyped 36 yakutensis fromChaun on four nuclear markers, of which three are located on the only divergent regions thatdiffers between the migratory phenotypes in Europe + CLOCK gene (a candidate for timing ofmigration). Analyzes revealed that yakutensis, despite strong differences in migration direction,distance, timing and wintering ground location cannot be separated from acredula genetically.

A critical step in ecological speciation is the development of reproductive isolation. The processes leading up to reproductive isolation are difficult to study since they often occur over very long time periods. Populations of European whitefish (Coregonus lavaretus) has gone through reticulate divergent evolution in many Scandinavian lakes during the last 10 000 years. Some populations even exhibit morphological and genetic divergence that involves adaptations to different niches during the first 100-200 years after introduction. This observed rapid diversification into different ecological niches makes whitefish a useful model species for studying ecological speciation and early population divergence. By assessing divergence for three traits in recently introduced whitefish populations, this study aims to elucidate the processes that lead to adaptive phenotypic divergence and reproductive isolation. Whitefish populations of known age (71-170 years) were sampled on their spawning grounds and characterized with respect to, 1) length of spawning season, 2) temporal segregation based on body size, and 3) temporal segregation based on the number of gill rakers. I found that the length of the spawning season and body size differences between early and late spawners increased with population age. No such trend was observed for differences in gill rakers between early and late spawners, but significant divergence within some of the older populations was detected. I conclude that these young whitefish populations have taken the first steps toward reproductive isolation between ecotypes that differs in body size (a highly plastic trait) and gill raker numbers (a trait under strong genetic control).

Life-history is the study of all the different stages of life that affect reproductive success and survival between the birth and death of an organism. The reproductive output of an organism is constrained by many things including time, resource, disease agents and environmental conditions. In addition, lineage-specific traits and the limitations of the physiological systems can limit how an organism responds to ecological processes, and thus constrains the variation of life histories represented in nature. Central to the theory of life history are the trade-offs that organisms make during their lifetime to maximise their reproductive potential. In this thesis, I focus on the effect of haemosporidian blood parasites on host life history, in relation to the glucocorticoid response and environmental conditions. The host study species is a population of collared flycatchers (Ficedula albicollis), a species that provides bi-parental care, located in the south of Gotland. We show that nestling condition predicts parasite infection and that parasite-mediated selection can start early on in the birds’ life. We also found a link between Lower levels of glucocorticoids and parasite infection, which might indicate a trade-off between immunity and reproductive effort. Adult birds’ upregulated glucocorticoids in response to an increase in reproductive effort and a predictable change in energy demand during reproduction. I also show that glucocorticoids respond to changing environmental conditions. These results together accentuate the importance of the plasticity of the glucocorticoid response to reproductive success. Moreover, higher levels of hormone during reproduction predicted survival to the next breeding season. In nestlings, glucocorticoid levels increased as a consequence of parent infection status and an increase in reproductive effort. Overall, our results indicate that the glucocorticoid response is context dependent. Finally, female collared flycatchers might pay a fitness cost as a consequence of parasite infection, but can still reproduce successfully suggesting that they can tolerate the parasite. To further our understanding of costs related to parasite infection, we must understand better the mechanisms that enable the host to tolerate infection. This study indicates that glucocorticoids provide a useful tool to detect how wild birds respond to predictable and unpredictable challenges.

Sexual reproduction entails complex co-evolution between the sexes, necessary for successful fertilization, ensuring individual and population-level fitness. Interfertility is the main criterion for species definition and understanding speciation requires detailed studies of reproductive barriers. However, many studies on reproductive barriers are constrained to infer evolutionary processes from patterns. In this thesis, I focus on a hybrid zone between collared and pied flycatchers (Ficedula albicollis and hypoleuca) on the island of Öland, and a trait that is essential for fertilization: sperm. Long-term monitoring of these species, combined with recent advances in molecular tools, allow me to study how complex on-going intersexual and interspecific interactions influence reproductive isolation in this young hybrid zone. I start by exploring the links between pre- and postmating sexual selection within collared flycatchers (paper I and II). I show that secondary sexual characters and indirect mate-choice benefits are tightly linked to physiology (paper I), and that a male’s attractiveness and dominance status dictate which sperm traits are optimal, as a male’s fertilization success depends on an interaction between sperm and display traits (paper II). I then report a source of strong postzygotic isolation between recently diverged collared and pied flycatchers: impaired spermatogenesis resulting in absence of mature sperm cells in hybrid males (paper III). I show however that pied flycatcher females, who are most exposed to hybridization, can mitigate these costs through mechanisms of cryptic female choice impairing heterospecific sperm performance, allowing them to bias paternity towards pure-species offspring (paper IV). Finally, by exploring the testes transcriptomes and sperm proteomes of both species, I highlight the importance of gene and protein regulation mechanisms in facilitating phenotypic divergence between these species (paper V). Thus, my thesis reveals complex interactions between primary and secondary sexual characters in a wild bird and suggests that mechanisms of sexual selection are tightly linked to essential physiological functions. I also show that genetic incompatibilities can evolve rapidly despite low genome-wide levels of divergence but that divergence in regulatory regions and proteins potentially allows fast evolution of molecular mechanisms impairing or preventing costly heterospecific fertilization.