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Simulation of processes predicted by theory of frozen plasticity
Nekola, Ondřej ; Flegr, Jaroslav (advisor) ; Ponížil, Petr (referee)
The question of the tempo of evolution is amongst the oldest conundrums in evolutionary biology and has not been satisfactorily answered yet. One of the attempts to do so is the frozen plasticity theory, which postulates that a sexually reproducing species is only capable of evolution within short periods of time after its genetic polymorphism decreases e.g. as a consequence of peripatric speciation. In the longer periods of evolutionary stasis, its evolution is limited by frequency- dependent selection and pleiotropy. In this work, I have produced an open source software simulating the respon- ses of populations of sexually reproducing individuals to varying environmental conditions. Using this software, I simulated evolution of populations with different probabilities of arising of alelles affecting more phenotypic traits and frequency- dependent selected alleles that have opposing phenotypic effects when present at the locus in one copy, respectively two copies. I observed trends predicted by the theory of frozen plasticity: slower adap- tation to instant environmental changes, lower achieved fitness and more frequent extinctions of populations with higher portions of investigated types of alleles, but only with low effect sizes and without statistical significance. For future research, it would be desirable...
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Conformity and eccentricity; driving forces of cultural evolution
Kutsos, Peter ; Tureček, Petr (advisor) ; Šaffa, Gabriel (referee)
When deciding between alternative strategies, animals often have to operate with limited or conflicting information. In these situations, what source of information they prioritize can make a huge difference. Individuals relying on social information (social learners) economize on costs like the risk of eating the wrong food or the energy needed to survey the environment but run the risk of the information they use being out of date or of low quality. On the other hand, those who prioritize individual learning can be more confident in the accuracy of their information, but without any social learning are forced to "reinvent the wheel" every generation. Natural selection has shaped several adaptive heuristic rules which help inform social learning. One category of these rules is frequency-dependent, which means that the probability of behavioural pattern acquisition depends on how common (or rare) they are in a population. This work is a literature review regarding two such rules: conformity and anticonformity and the roles they play in cultural evolution. Keywords: Frequency-dependent transmission, cultural evolution, social learning, conformity bias, anticonformity
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Evolutionary aspects of (epi)genetic determination of laterality with a special focus on upper limb
Holoubková, Tereza ; Daňková, Pavlína (advisor) ; Struška, Michal (referee)
Handedness is one of the most distinct asymmetries of the human body. There is approximately 90 % of right-handers in the population, which is the strongest bias in handedness among all primates. Handedness is connected with lateralization of brain for language and is determined both genetically and by the environment. Genetic determination of the handedness has not been yet figured out, although there are many candidate genes and regions. In addition to candidate genes, the genetic determination is shaped by the epigenetic mechanisms and the role of testosterone. Handedness occurred alongside the beginning of the human population development, approximately in the Middle Pleistocene, with the same percentage of left-handers as today. Handedness polymorphism is maintained in the population based on the frequency-dependent model because of the advantages and disadvantages associated with left-handedness.
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Simulation of processes predicted by theory of frozen plasticity
Nekola, Ondřej ; Flegr, Jaroslav (advisor) ; Ponížil, Petr (referee)
The question of the tempo of evolution is amongst the oldest conundrums in evolutionary biology and has not been satisfactorily answered yet. One of the attempts to do so is the frozen plasticity theory, which postulates that a sexually reproducing species is only capable of evolution within short periods of time after its genetic polymorphism decreases e.g. as a consequence of peripatric speciation. In the longer periods of evolutionary stasis, its evolution is limited by frequency- dependent selection and pleiotropy. In this work, I have produced an open source software simulating the respon- ses of populations of sexually reproducing individuals to varying environmental conditions. Using this software, I simulated evolution of populations with different probabilities of arising of alelles affecting more phenotypic traits and frequency- dependent selected alleles that have opposing phenotypic effects when present at the locus in one copy, respectively two copies. I observed trends predicted by the theory of frozen plasticity: slower adap- tation to instant environmental changes, lower achieved fitness and more frequent extinctions of populations with higher portions of investigated types of alleles, but only with low effect sizes and without statistical significance. For future research, it would be desirable...
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The role of minority type preference in human sexual selection
Pokorný, Šimon ; Kleisner, Karel (advisor) ; Třebický, Vít (referee)
Minority phenotype preference, or the negative frequency-dependent selection is a type of selection, where a feature is more preferred, the lower it's frequency is in the population. Even a weak effect in other-preference based sexual selection can result in a sustainable polymorphism. This study reviews the phenomenon in the context of human visual facial features. Common trends in attractiveness shape the morphology of the human face towards uniformity. Individual recognition however, as a condition for most social relations, uses the wast variability of different features. This variability could be formed and maintained by minority phenotype preference. In our study we tested the effect of minority phenotype preference in the selection for rare hair and eye colors. In 120 unique sets, each containing six photographs, we experimentally manipulated the frequency of each color type. These sets were then shown to 226 human raters. We tested whether the relative frequency of each color type affected the rating of individual stimuli. In hair color, significant effect of minority phenotype preference was detected when females rated the photographs of men. When males rated the photographs of females, the effect was significant in eye color only. Key words: face perception, sexual selection,...
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