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Bacterial species – from theory to practice

100%
Bartoszewicz M.
Edukacja Biologiczna i Środowiskowa
|
2018
|
issue 1
3-7
EN
Although the Mayr’s definition of species is commonly accepted for eukaryotic organisms, bacteria do not meet those established criteria. Thus, a special approach is necessary to elaborate the definition resistant to such limitations as for example the lack of sexual reproduction or horizontal gene transfers. One of the most problematic taxa in microbiology is the Bacillus cereus group composed of several closely related bacteria. Thus, on the basis of this model, doubts concerning bacterial taxonomy are discussed in the light of actual, molecular data.
2
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Odwieczność - okiem przyrodnika czyli meandry filogenezy świata zwierząt

75%
Blaszak C.
Zeszyty Naukowe Centrum Badań im. Edyty Stein
|
2016
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issue 15
13-34
PL
In the present review, an attempt to define the animal kingdom against a background of other kingdoms in the domain of eukaryotic organisms is presented,showing the common features linking the animal kingdom with the kingdom of fungi.The animals were clearly separated from other kingdoms through two unique systemscharacteristic of them: nervous and muscular. The matter is complicated by the fact that in the four types of the animal kingdom (Porifera, Placozoa) the nervous and muscular systems are absent. Therefore, zoologists proposed the name Metazoa multicellularanimal – for the animal kingdom. The main problematic issues of monophyly based onselected phylogenetic groups and phyla are discussed. In addition to the phylogenetictree (based on monophyly) the punctuated equilibrium was established for four independentgroups: Porifera, Cnidaria, Protostomia, Deuterostomia. Finally, the position ofthe animal kingdom in the monophyletic point of view and against a background of all other organisms is presented.
3
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Creating new concepts in mathematics: freedom and limitations. The case of Category Theory

75%
Semadeni Z.
Zagadnienia Filozoficzne w Nauce
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2020
|
issue 69
33-65
EN
In the paper we discuss the problem of limitations of freedom in mathematics and search for criteria which would differentiate the new concepts stemming from the historical ones from the new concepts that have opened unexpected ways of thinking and reasoning. We also investigate the emergence of category theory (CT) and its origins. In particular we explore the origins of the term functor and present the strong evidence that Eilenberg and Carnap could have learned the term from Kotarbiński and Tarski.
4
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Stan biologiczny populacji ludzkich a przemiany środowiska społeczno-ekonomicznego

63%
Siniarska A., Wolański N.
Studia Ecologiae et Bioethicae
|
2006
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vol. 4
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issue 1
17-41
EN
Adaptation of life to the environment occurs at two levels - that of an individual and that of a population. In the first step of the process of adaptation variability is produced. It provides necessary material for the second step - selection. Variability is generated during the phylogeny, from one generation to the next. However, variability can also be generated during individual ontogeny at least by protective mechanisms of instinctive behaviors of animals and conscious cultural human actions. Variability originates from point mutations and chromosomal aberrations occurring during transmission of genetic material from generation to generation and through activation, or deactivation, of genes that alters their expression. This variability determines phenotypic differences among individuals. Variability thus produced is subjected to selection because how a phenotype is formed determines its ability to survive and to produce offspring. In human populations, adaptation occurs via biological and via cultural processes. Humans with their culture - especially medicine and social care - protect lives of individuals who otherwise would have been eliminated by natural selection.Hereditary differences among various geographic groups of modern people occur with low frequency - just a fraction of a percentage point. From observations of phenotypes it can be concluded that both structural alterations in the DNA and differences in gene expression cause variations, the majority of genes are inactive at various stages of ontogeny, while various portions of the genotype become active at different times in the life of an individual.Environment influences variation in three ways: (1) by causing mutations or by altering gene expression and (2) by providing conditions for the formation of a phenotype coded by a particular genotype and (3) as a factor of selection, including occurrence of cultural behaviors modifying effects of natural selection. It seems that the main aim of future research in human ecology should be search for the answer to following questions: 1. Can gene expression be changed during ontogeny? 2. To what extent such changes can be inherited? 3. To what extent is there an increase in the occurrence of genes that do not allow survival without special care (genetic load), and 4. How will all this influence future of our species? 
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