Lärares beskrivningar av evolution som undervisningsinnehåll i biologi på gymnasiet

Biological evolution is part of the syllabi for Biology and Science in Swedish upper secondary school. In the syllabi, evolution is not only presented as a topic in Biology courses, but is also regarded as a unifying theme. The teacher has a fundamental role in deciding how the national curriculum is translated into the educational situation. This thesis investigates teachers’ accounts of their teaching of evolution in Swedish upper secondary school, describing their understandings of the purpose of teaching and learning evolution as part of biology education. The thesis is based on interviews of teachers teaching the course Biology A, which is compulsory as dictated by the Natural Science Program. The interviews were supplemented with questionnaires. The interviews were orientated towards questions about selection of course content and the reasons for choosing this content. The interviews were focused on teachers experiences based on their own practice. Two aspects of content were examined: (1) the scientific content taught in terms of themes and (2) the socializing value-laden aspects, such as priorities taken by the teachers and the teachers´ overarching aims.   The results showed that teachers described different teaching contents with regard to values, even when the core content of themes was similar. Four different selective traditions for choosing content were identified among teachers. The results are discussed in relation to the context and conditions that the teachers identify as influential on the content chosen. Teachers’ interactions with their students as well as their world views are important for their selection and adjustment of content. There are also indications that teachers’ personal views about purposes are important for selecting the teaching content.

Biology Teachers'Conceptions of the Diversity of Life and the Historical Development of Evolutionary Concepts

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Telomeres: Linking stress and survival, ecology and evolution.

Telomeres are protective structures at the ends of eukaryotic chromosomes. The loss of telomeres through cell division and oxidative stress is related to cellular aging, organismal growth and disease. In this way, telomeres link molecular and cellular mechanisms with organismal processes, and may explain variation in a number of important life-history traits. Here, we discuss how telomere biology relates to the study of physiological ecology and life history evolution. We emphasize current knowledge on how telomeres may relate to growth, survival and lifespan in natural populations. We finish by examining interesting new connections between telomeres and the glucocorticoid stress response. Glucocorticoids are often employed as indices of physiological condition, and there is evidence that the glucocorticoid stress response is adaptive. We suggest that one way that glucocorticoids impact organismal survival is through elevated oxidative stress and telomere loss. Future work needs to establish and explore the link between the glucocorticoid stress response and telomere shortening in natural populations. If a link is found, it provides an explanatory mechanism by which environmental perturbation impacts life history trajectories.

Pioneers of evolution from Thales to Huxley : with an intermediate chapter on the causes of arrest of the movement /

pt. I. Pioneers of evolution from Thales to Lucretius, B.C. 600-A.D. 50 -- pt. II. The arrest of enquiry A. D. 50-A. D. 1600: 1. From the early Christian period to the time of Augustine, A.D. 50-A.D. 400. 2. From Augustine to Bacon, A. D. 400-A. D. 1600 -- pt. III. The renascence of science, about A. D. 1600 onwards -- pt. IV. Modern evolution: 1. Darwin and Wallace 2. Herbert Spencer. 3. Thomas Henry Huxley.

Evolution : its nature, its evidences, and its relation to religious thought /

Microform.

Biology, with preludes on current events /

At head of title: Boston Monday lectures.

The evolution of man : a popular exposition of the principal points of human ontogeny & phylogeny /

Bound in green publisher's cloth with gilt-stamped spine, blind-stamped boards, and yellow coated endpapers.

DNA-Directed DNA Polymerases Evolve From Reverse Transcriptase

Scientists have been debating for decades the origin of life on earth. A number of hypotheses were proposed as to what emerged first RNA or DNA; with most scientists are in favour of the "RNA World" hypothesis. Assuming RNA emerged first, it fellow that the RNA polymerases would've appeared before DNA polymerases. Using recombinant DNA technology and bioinformatics we undertook this study to explore the relationship between RNA polymerases, reverse transcriptase and DNA polymerases. The working hypothesis is that DNA polymerases evolved from reverse transcriptase and the latter evolved from RNA polymerases. If this hypothesis is correct then one would expect to find various ancient DNA polymerases with varying level of reverse transcriptase activity. In the first phase of this research project multiple sequence alignments were made on the protein sequence of 32 prokaryotic DNA-directed DNA polymerases originating from 11 prokaryotic families against 3 viral reverse transcriptase. The data from such alignments was not very conclusive. DNA polymerases with higher level of reverse transcriptase activity were non-confined to ancient organisms, as one would've expected. The second phase of this project was focused on conditions that may alter the DNA polymerase activity. Various reaction conditions, such as temperature, using various ions (Ni2+, Mn2+, Mg2+) were tested. Interestingly, it was found that the DNA polymerase from the Thermos aquatics family can be made to copy RNA into DNA (i.e. reverse transcriptase activity). Thus it was shown that under appropriate conditions (ions and reactions temperatures) reverse transcriptase activity can be induced in DNA polymerase. In the third phase of this study recombinant DNA technology was used to generate a chimeric DNA polymerase; in attempts to identify the region(s) of the polymerase responsible for RNA-directed DNA polymerase activity. The two DNA polymerases employed were the Thermus aquatic us and Thermus thermophiles. As in the second phase various reaction conditions were investigated. Data indicated that the newly engineered chimeric DNA polymerase can be induced to copy RNA into DNA. Thus the intrinsic reverse transcriptase activity found in ancient DNA polymerases was localized into a domain and can be induced via appropriate reaction conditions.

Morphologie évolutive et fonctionnelle des hémichordés

L’embranchement Hemichordata regroupe les classes Enteropneusta et Pterobranchia. Hemichordata constitue, avec l’embranchement Echinodermata, le groupe-frère des chordés. Les entéropneustes sont des organismes vermiformes solitaires qui vivent sous ou à la surface du substrat et s’alimentent généralement par déposivorie, alors que les ptérobranches sont des organismes coloniaux filtreurs habitant dans un réseau de tubes appelé coenecium. Ce mémoire présente trois études dont le point commun est l’utilisation des hémichordés actuels pour répondre à des questions concernant l’évolution des hémichordés, des chordés, et du super-embranchement qui les regroupe, Deuterostomia. Notre première étude démontre que les fentes pharyngiennes, l’organe pré-oral cilié (POCO) et le pharynx de l’entéropneuste Protoglossus graveolens sont utilisés pour l’alimentation par filtration. Le système de filtration de P. graveolens permet la capture de particules jusqu’à 1.3 um, à un débit de 4.05 mm.s-1, pour une demande énergétique de 0.009 uW. Les similarités structurales et fonctionnelles avec le système de filtration des céphalochordés suggèrent que la filtration pharyngienne est ancestrale aux deutérostomes. Lors de notre deuxième étude, nous avons exploré l’hypothèse selon laquelle le POCO des entéropneustes, une structure ciliée pré-buccale au rôle possiblement chémorécepteur, serait homologue au « wheel organ » des céphalochordés et à l’adénohypophyse des vertébrés. Pour cela, nous avons déterminé par immunohistochimie l’expression de Pit-1, un facteur de transcription spécifique à ces deux structures, chez l’entéropneuste Saccoglossus pusillus. Pit-1 est exprimé dans des cellules sensorielles du POCO, mais aussi dans des cellules épithéliales distribuées dans le proboscis, collet et tronc. Ce patron d’expression ne permet pas de confirmer ou rejeter l’homologie du POCO et de l’adénohypophyse des vertébrés. Lors de notre troisième étude, nous avons caractérisé l’ultrastructure du coenecium des ptérobranches Cephalodiscus hodgsoni, Cephalodiscus nigrescens et Cephalodiscus densus par microscopie électronique à transmisison et à balayage. Cephalodiscus est le groupe frère de Graptolithina, un groupe qui inclut les graptolithes éteints ainsi que les ptérobranches du genre Rhabdopleura. Nous avons décrit les types de fibrilles de collagène présents, leur taille et leur organisation, ainsi que l’organisation globale du coenecium. Nous avons ainsi démontré la présence chez Cephalodiscus d’une organisation similaire au paracortex, pseudocortex et eucortex des graptolithes. La présence chez Cephalodiscus de ce type d’organisation suggère que le cortex est ancestral à la classe Pterobranchia. Ces trois études illustrent plusieurs axes importants de la recherche sur les hémichordés, qui en intégrant des données morphologiques, fonctionnelles et moléculaires permet de reconstruire certains évènements clés de l’évolution des deutérostomes.

Évolution à fine échelle des sites d'épissage des introns dans les gènes des oomycètes

Les introns sont des portions de gènes transcrites dans l’ARN messager, mais retirées pendant l’épissage avant la synthèse des produits du gène. Chez les eucaryotes, on rencontre les introns splicéosomaux, qui sont retirés de l’ARN messager par des splicéosomes. Les introns permettent plusieurs processus importants, tels que l'épissage alternatif, la dégradation des ARNs messagers non-sens, et l'encodage d'ARNs fonctionnels. Leurs rôles nous interrogent sur l'influence de la sélection naturelle sur leur évolution. Nous nous intéressons aux mutations qui peuvent modifier les produits d'un gène en changeant les sites d'épissage des introns. Ces mutations peuvent influencer le fonctionnement d'un organisme, et constituent donc un sujet d'étude intéressant, mais il n'existe actuellement pas de logiciels permettant de les étudier convenablement. Le but de notre projet était donc de concevoir une méthode pour détecter et analyser les changements des sites d'épissage des introns splicéosomaux. Nous avons finalement développé une méthode qui repère les évènements évolutifs qui affectent les introns splicéosomaux dans un jeu d'espèces données. La méthode a été exécutée sur un ensemble d'espèces d'oomycètes. Plusieurs évènements détectés ont changé les sites d’épissage et les protéines, mais de nombreux évènements trouvés ont modifié les introns sans affecter les produits des gènes. Il manque à notre méthode une étape finale d'analyse approfondie des données récoltées. Cependant, la méthode actuelle est facilement reproductible et automatise l'analyse des génomes pour la détection des évènements. Les fichiers produits peuvent ensuite être analysés dans chaque étude pour répondre à des questions spécifiques.

Out of Amazonia again and again: episodic crossing of the Andes promotes diversification in a lowland forest flycatcher

Most Neotropical lowland forest taxa occur exclusively on one side of the Andes despite the availability of appropriate habitat on both sides. Almost all molecular phylogenies and phylogenetic analyses of species assemblages (i.e. area cladograms) have supported the hypothesis that Andean uplift during the Late Pliocene created a vicariant barrier affecting lowland lineages in the region. However, a few widespread plant and animal species occurring in lowland forests on both sides of the Andes challenge the generality of this hypothesis. To understand the role of the Andes in the history of such organisms, we reconstructed the phylogeographic history of a widespread Neotropical flycatcher (Mionectes oleagineus) in the context of the other four species in the genus. A molecular phylogeny based on nuclear and mitochondrial sequences unambiguously showed an early basal split between montane and lowland Mionectes. The phylogeographic reconstruction of lowland taxa revealed a complex history, with multiple cases in which geographically proximate populations do not represent sister lineages. Specifically, three populations of M. oleagineus west of the Andes do not comprise a monophyletic clade; instead, each represents an independent lineage with origins east of the Andes. Divergence time estimates suggest that at least two cross-Andean dispersal events post-date Andean uplift.

Wolves in sheeps' clothing: Creationist manipulation of Kansas science standards

So the question that animates this paper is this: what happens when a state's education policy seeks to make popular social and religious values a central part of its education standards in direct confrontation with the Establishment Clause of the First Amendment of the U.S. Constitution? I will try to answer that question in three ways. First, I will examine the tactics used in the manipulation of curricula to reflect social and religious values, with special focus on the Kansas case. Second, I will try to ascertain the determinants of success in these efforts; under what conditions are movements to impose creation science on public school curricula likely to succeed, and when to fail? Third, I will try to place these struggles over educational curricula, and between religion and science, in broader context, focusing on what they tell us about the nature of public policy making in the contemporary United States.

Adventures of punctuated equilibria : a struggle for authority in the evolutionary sciences

The theory of ‘punctuated equilibria’ was formulated by two paleontologists, Niles Eldredge and Stephen Gould, in 1972 and has been the focus of considerable controversy within the evolutionary sciences ever since. The primary intentions of this thesis are to relate the history of punctuated equilibria and to examine how it has affected evolutionary science. Several modes of analysis have been used to illuminate the history: The sociological perspectives of Pierre Bourdieu and Bruno Latour (who see scientific debate as a ‘struggle for authority’); Rhetorical analysis of some of the key documents; Communication with practising scientists via questionnaires and correspondence; Citation Analysis. Chapter 1 gives a short summary of the history and introduces the methods and socio-philosophical perspectives used to illuminate the history. Chapters 3 and 4 examine the rhetorical process by which Eldredge and Gould constructed the ‘punctuationist revolution’. Chapters 2, 3, 5 and 6 relate the history of punctuated equilibria.