National Repository of Grey Literature 11 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Macroevolutionary and ecological implications of the theory of frozen plasticity
Toman, Jan ; Flegr, Jaroslav (advisor) ; Fatka, Oldřich (referee) ; Mikuláš, Radek (referee)
The frozen plasticity theory is a punctuationalist theory of adaptive evolution. It states that long periods of stasis, during which populations respond to selection pressures only by elastic change in the frequency of already present alleles, alternate in the evolution of sexual species with short periods of plastic evolution, during which alleles can get fixed or eliminated by directed selection. Asexual species are not expected to maintain such high genetic polymorphism in the long term. They should, however, be able to plastically respond to selection pressures throughout their whole existence. This difference between the evolutionary dynamics of sexual and asexual clades has a number of ecological and macroevolutionary implications. Concerning ecology, we could expect different environmental preferences of sexual and asexual species. Accordingly, in our first work that was based on a comparative study, we statistically significantly supported the hypothesis that (ancient) asexual groups of (eukaryotes) inhabit more stable and homogeneous habitats than their related sexual controls. Focusing on actually experienced, i.e. subjective, heterogeneity of the environment turned out to be the crucial factor of this type of research. From the viewpoint of macroevolutionary implications of the frozen...
Simulations of open-ended evolution
Prax, Sebastian ; Toman, Jan (advisor) ; Tureček, Petr (referee)
Evolutionary algorithms are used to solve a number of optimization problems in the computer science. At the same time, they are fundamental pillar for creating evolutionary simulations and testing scientific hypotheses in a various areas of theoretical biology. In the first half of my work, I characterize the concept of "open-ended evolution", focus on its connection with the technical side of simulations and introduce readers to the problematics of system simulation. Further on, I deal with the phenomenon of increasing complexity and the idea of "evolutionary progress". All these topics are confronted with various perspectives of researchers in the field of evolutionary biology. In the second half, I summarize the benefits of existing projects for evolutionary biology and applied informatics, as well as the ways in which the simulations of open-ended evolution can be approached. Basically, these projects can be divided into two categories. They are either projects in which individuals develop towards a predefined goal, which is conditioned by a fitness function, or projects of researchers who seek to achieve an open-ended evolution by employing biologically realistic design of the genetic code and environment in conjunction with the absence of a particular attractor in the evolution of virtual...
Rak mexický {Cambarellus patzcuarensis} - přehledová studie
TOMAN, Jan
Indigenous crayfish are increasingly threatened by their non-indigenous counterparts, which species are often more tolerant and adaptable. In case of North American species, they are also chronic carries of crayfish plague, a disease mostly lethal to crayfish of non-North American origin. In this bachelor thesis entitled "Mexican dwarf crayfish (Cambarellus patzcuarensis) - an overview", there is a summary containing available information about the Mexican dwarf crayfish, while main, so far unknown biological features of this species, are defined. Nowadays, this crayfish is one of the most bred and sold crayfish within the pet trade. However, its introductions can lead to unwanted alterations in newly occupied ecosystems. This overview of the available information on the Mexican dwarf crayfish and the definition of so far insufficiently known aspects of its biology can serve as a valuable basis for follow-up studies.
Multilevel selection theory
Mihulka, Tomáš ; Švorcová, Jana (advisor) ; Toman, Jan (referee)
Multilevel selection is an attempt to unify different approaches to the Level of selection problem. This paper examines the principles, starting points, variants and problems of this concept. Particular emphasis is placed on the relationship of this theory to Gene's-eye view and the presentation of evidence of the usefulness of Multilevel selection in analyzing evolutionary changes.
Conceptions about the Origin of Life in Science vs. High School Textbooks
Vávrová, Anna ; Dvořáková, Radka (advisor) ; Toman, Jan (referee)
The theory of the origin of life in lessons of biology in secondary schools - this topic is limited on concepts such as abiogenesis, panspermia, creationism, biological and chemical evolution in textbooks. What was written in textbooks years ago is, in many cases, no longer upto date. The aim of this bachelor thesis is to summarize the most recent scientific pieces of knowledge relevant to the topic of the origin of life and ensuingly compare them with the material that is presented to students at secondary schools. This bachelor thesis consists of three parts, where the first is a literary research focused on technical scientific articles dealing with the topic of the origin of life (cell). The following part contains a research of the contents of educational material and textbooks, and I compare the two previous parts in the last one. My effort is to point out information that can already be mistaken or archaic, and are being lectured to students as facts in secondary schools. After comparing the current knowledge with the contents of the textbooks I have used today, I would recommend the actual interpretation to be updated by the information that has been enriched in the past years.
Armenian community in the Czech Republic
Toman, Jan ; Pargač, Jan (advisor) ; Šatava, Leoš (referee)
This thesis deals with the life of Armenian immigrants in the Czech Republic, especially in Prague Armenian community. The thesis begins with a theoretical part, which contains two chapters. The first chapter deals with the ethnogenesis and history of the nation. The historical part is discussed rather briefly, but seeks all the moments that were crucial for the Armenians. In the second chapter, I write about important incentives for migration and the global Armenian diaspora. The main part of the thesis is based on field research among the migrants, which ran from February to April 2013. This chapter resolves the issue migration, integration into the new environment, the identity of Armenians, community relations and relations with other nations. I also document here the overall opinion of the Armenians on the Czech Republic. The last chapter is the result of a questionnaire survey among the citizens of Czech nationality, to detect their knowledge and opinion about Armenia and Armenians.
The role of ecological factors in maintenance of sexuality
Toman, Jan ; Flegr, Jaroslav (advisor) ; Janko, Karel (referee)
The existence and widespread distribution of sexual reproduction despite its obvious disadvantages is an evolutionary enigma. According to the theory of frozen plasticity, the evolution of sexual and asexual species is fundamentally different. One of the implications of this theory are different ecological preferences of these species. Sexual species should prefer biotically and abiotically variable environments because of their ability to quickly and reversibly respond to unpredictable changes. On the other hand, asexual species should prosper in biotically and abiotically stable environments because of their ability to perfectly adapt even to extreme environmental factors in the long term. I decided to test these predictions in the metastudy comparing ancient asexual clades (in which we can be sure about their obligate asexuality and evolutionary longevity) with their sexual sister or closely related ecologically comparable clades. The hypothesis of the preference of asexual species to biotically and abiotically homogenous environments was supported by the results of this metastudy. On the other hand, the hypothesis of supposed ability of asexual species to perfectly adapt to a broader range of environmental conditions, tested on the comparison of temperature ranges of activity of previously...
Ecological aspects of sexual reproduction
Toman, Jan ; Flegr, Jaroslav (advisor) ; Markoš, Anton (referee)
Sexual reproduction is one of the most interesting biological phenomena. No theory has ever entirely explained its wide occurrence among Eukaryotic clades despite its clear disadvantages (e.g. twofold price of sex). Theories can be divided into three groups according to the approach to solve this problem - molecular, genetic and ecological (environmental). Environmental theories are slightly preferred in the last decades and the opinion that the key to the sex enigma lies among them is widely accepted. Most of the environmental theories do not counter each other and there is possibility either to integrate them in several ways or presume that several of these theories might act simultaneously. According to theories, abiotically stable environments without biotic interactions (homogenous) should be suitable for and select for asexual species, whereas environments abiotically variable and rich in biotic interactions (heterogenous) should be suitable for and select for sexual species. The anagenetic phenomenon of punctuated equilibria and some of its explanations, e.g. P. R. Sheldon's Plus ça change hypothesis or J. Flegr's Frozen plasticity theory, also supports this division. There is a vast amount of empirical data supporting this division in ecological studies. Clearly homogenous environments...
Storage and dispatch hall including the reconstruction - building-technology project
Toman, Jan ; Štěrba, Martin (referee) ; Henková, Svatava (advisor)
Subject of this thesis is construction technology project storage and dispatch hall in Třebíč. This thesis contains technical report, construction site equipment project, time and financial plan, bill of quantities, technology study of the major technology stages, mechanical assembly design, technological specification, quality inspections.
Technological phase substructure - Business center in Ostrava
Toman, Jan ; Štěrba, Martin (referee) ; Henková, Svatava (advisor)
Subject of this thesis is the lower gross production technology mall in Ostrava. This work contains exactly technical reports, technological specification, site equipment, mechanical assembly design, scheduling, budgeting, monitoring and test plans, safety and environmental protection.

National Repository of Grey Literature : 11 records found   1 - 10next  jump to record:
See also: similar author names
7 TOMAN, Jan
3 Toman, Jakub
1 Toman, Jaroslav
11 Toman, Jiří
4 Toman, Josef
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