|
|
Seasonality of reproduction in tropical birds
Kačírek, Vojtěch ; Sedláček, Ondřej (advisor) ; Tomášek, Oldřich (referee)
The aim of of this paper is to summarize the knowledge of reproduction seasonality of tropical birds. Work includes characteristics of individual tropical environment and changes in abiotic conditions, focusing on the question, in what sense are tropics aseasonal and what is not. The work includes an overview of methodologies for collecting data during field research focused on monitoring reproduction in birds. The main part of this work is to compare the differences between biogeographic regions, regions and their stimuli, which most commonly lead to the creation of seasonal reproduction, followed by a comparison of individual functional groups of birds (food guilds). Powered by TCPDF (www.tcpdf.org)
|
|
|
Postcopulatory sexual selection
Kivader, Tomáš ; Reifová, Radka (advisor) ; Tomášek, Oldřich (referee)
Sexual selection is a key evolutionary process which affects transfer of gene's alleles to future generations. We distinguish precopulatory and postcopulatory sexual selection. Postcopulatory sexual selection is a type of sexual selection which takes place after copulation, more specifically after insemination. During precopulatory sexual selection same-sex individuals compete over the opportunity to reproduce. Simultaneously, males and females have different priorities. Males prefer quantity while females quality of offspring. So they compete in creating new strategies for increasing their own fitness. Consequently, sexual selection often leads to coevolution between males and females of the same species. Finally, this affects the segregation of individual populations and speciation. For establishing postcopulatory sexual selection it is important that multiple males are mating with the same female within the scope of one population. This is ensured by promiscuity or extra-pair copulations in various mating systems. There are two basic processes by which postcopulatory sexual selection is realized. Those are sperm competition and cryptic female choice. These mechanisms have not been explored in detail yet. Firstly, because monitoring postcopulatory processes in vivo is problematic, and secondly,...
|
|
|
Reproductive senescence in female barn swallows (Hirundo rustica): age-related changes in components of reproductive success
Pazdera, Lukáš ; Tomášek, Oldřich (advisor) ; Riegert, Jan (referee)
The effect of age on an individual's fitness is one of the key topics of evolution ecology. Currently intensively studied manifestation of age is an aging of organism, thus a deterioration of metabolic functions and condition with age. An increasing count of studies shows that aging in the wild is rather a rule than exception, even with short-lived species of which the aging has not been previously presumed at all. Despite an increasing interest of evolution ecologists in this matter, some important aspects remain overlooked. Senescence of the traits are usually studied separately, therefore, an information whether an individual traits show similar or different aging dynamics is missing. The information is needed to assess if the signs are aging synchronously, as predicted by the William's antagonistic pleiotropy theory, or rather asynchronously. The suitable traits for study are these, which are involved in a reproduction activity. The reproduction is a sequential process consisting of many components, e.g. an expression of sexual ornaments (attractivity), nesting timing, amount of eggs laid and their size, etc. There is currently a little knowledge of which of these reproduction components are affected by the aging the most, and which are resistant to the the effect of age. Well studied is...
|
|
|
Lipid composition of biological membranes and life-histories in songbirds
Šimonová, Kateřina ; Tomášek, Oldřich (advisor) ; Sam, Kateřina (referee)
Differences in the composition of cell membranes are considered to be the physiological mechanism responsible for different metabolic rates, life span and consequently, different life-histories. The membrane pacemaker theory suggests that higher membrane unsaturation may be an important factor responsible for higher metabolic rate and shorter life span of organisms. The alternative hypothesis, on the other hand, assumes that membranes can function as structural antioxidants, and thus that higher membrane unsaturation may be associated with longer life span. The aim of this work was to test how changes in the fatty acid composition of membranes depends on body size, latitude and altitude, within which different life-histories and metabolic rate were observed. Temperate and tropical lowland songbird species were chosen for the models testing the effect of latitude, and only tropical species of songbirds were chosen for the models testing the effect of altitude. Part of the work was molecular sex determination. Using gas chromatography and mass spectrometry, the amount of individual fatty acids contained in red blood cell phospholipids was obtained from blood samples. The results showed that the composition of the membranes in most cases correlates with body size, which also correlates with almost all...
|
|
|
Reproductive investment, body condition and survival in the barn swallow (Hirundo rustica)
Novotná, Kateřina ; Tomášek, Oldřich (advisor) ; Svobodová, Jana (referee)
Life history theory provides possible explanations for timing of important events which shape nature of both specific animal life cycles and acquisition of resources. Since the amount of available resources is limited, trade-off arises in an organism in how energy and time are invested into components that determine individual fitness. A key trade-off in life history theory is the one between resource allocation into reproduction and mechanism promoting homeostasis and survival. Increased investment in actual reproduction can have negative impact on condition and hence on future reproduction or survival. I explored relationships between reproduction, aspects of condition (haematology and ectoparasite prevalence) and survival in barn swallow (Hirundo rustica) population in South Bohemia. Mean brood size in actual season was positively correlated with survival in next breeding season in females but not in males. In addition, survival was positively correlated with number of nests in both sexes. These findings suggest that, apart from trade-off between reproduction and survival, variability of individual quality, condition or resource availability also influence their eventual relationship. High quality individuals that are more efficient in acquisition and utilisation of nutrients or other resources...
|
|
|
Signalling of personality and stress response by secondary sexual traits in a socially monogamous passerine
Tesař, David ; Tomášek, Oldřich (advisor) ; Sedláček, Ondřej (referee)
Secondary sexual traits play an irreplaceable role in the reproduction of a range of animals and are used as quality and fitness sensors during pairing of individuals. Expression of these traits, ornamentes, can correlated with an individual's personal and behavioral strategies. In the case of melanin ornaments, not only the relationships with personal individuals are considered, but there is the possible connections with stress resistance and the level of stress responses too. This hypothesis is based on the pleiotropic effect of the melanocortin system, which can be used during melanogenesis but also in the production of hormones that contribute to range of stress responses. The aim of this work was to clarify the relationship between an individual's ornaments, his stress response and individuality in the barn swallows (Hirundo rustica rustica). In this work the relationship between selected ornaments and the stress reaction of the organism, stressed glucose levels measured 15 minutes after a stress stimulus, was tested. Both sexes showed a correlation between area of white tail spots and stress response. Only for males a relationship with the length of outermost tail feathers was found and a correlation with the color saturation of feathers on the throat was shown for females. The second part of...
|
|
|
Critical swimming speed in intensively cultured European perch (\kur{Perca fluviatilis} L.): Influence of fish size, production system and repeated testing
TOMÁŠEK, Ondřej
Critical swimming speed and swimming performance in relation with different factors were tested this thesis in groups of European perch (Perca fluviatilis) with focus to utilize these results in intensive aquaculture. Thesis is consisted of four different experiments performed in swimming tunnel. In the first experiment were tested, if there are any differences in day distances of measuring between three groups of fish. Each group were measured three times. First group was measured in time (t) 0, 24 and 48 h, second group was measured in time (t) 0, 48 and 96 h. Finally, third group was measured in time (t) 0, 96 and 192 h. Second experiment was set to compare critical swimming speed in three weight categories of a fish. Weight categories of 100g, 200g and 250g were tested. In the third experiment were tested pond reared fish and aquaculture (RAS) reared fish. Results were compared together, if there are any differences. Last experiment was set to find out if there is any relationship between level of critical swimming speed and somatic indexes or fillet and caraccas yield. No one of experiments performed confirm expectations of results. In the first experiment was found that there no effect of repeated swimming tests on critical swimming speed as well as no effect of different recovery period (from previous test). In comparison of different weight categories were measured highest levels of critical swimming speed in 100g group without decreasing trend in for bigger size categories (200 and 250 g). Pond and intensively reared fish had same level in critical swimming speed. Moreover, fourth experiment did not confirm influence level of critical swimming speed to somatic indexes or fillet yield. Results of presented thesis can contribute on better technical design of rearing units for this gastronomically and economically interesting species in intensive aquaculture, mainly in RAS systems.
|
|
|
Condition dependence of sexually selected ornaments in birds
Tomášek, Oldřich ; Albrecht, Tomáš (advisor) ; Verhulst, Simon (referee) ; Šálek, Miroslav (referee)
Sexual ornaments important for mating success in many species are often assumed to evolve as condition-dependent signals of individual quality. Ornament expression can be associated with age and survival, thereby signalling individual viability. Here, we have tested viability signalling function of tail streamers and their importance for within-pair and extra-pair fertilisation success in the European barn swallow (Hirundo rustica rustica). In contrast to previous studies on this subspecies, our data suggest that tail length is not associated with fertilisation success in our population. Instead, the most important predictors of within-pair and extra-pair fertilisation success were female and male age, respectively. Our data supported viability signalling function of male tail streamers, as documented by age-related within- individual increase in their length. There was no evidence for senescence in this trait. Contrary to some previous studies, the viability signalling function of tail streamers was further supported by observed selective disappearance of males with shorter tails. Several physiological mechanisms have been proposed as maintaining signalling honesty. Among them, oxidative stress from highly reactive species (RS), including free radicals, attracted a considerable attention. Given...
|
|
|
Lipid composition of biological membranes as a pace-maker of metabolic rate and life-histories
Šimonová, Kateřina ; Tomášek, Oldřich (advisor) ; Vojtek, Libor (referee)
Slože í iologi ký h e rá á zásad í vliv a pol e as e é ast é k seli , jako je apříklad DHA, jsou vel i itlivé k poškoze í vol ý i radikál , oproti o o e as e ý MUFA a as e ý SFA ast ý k seli á . předpokladu, že spolu s e as e ostí e rá se zv šuje o idač í u poškoze í a ásled ě r hlost stár utí, vz ikla a e akerová teorie stár utí Tato h potéza je slože á ze dvou částí. Prv í z týká souvislosti ezi slože í e rá a délkou života, kd živoči hové s ví e e as e ý i e rá a i s v šší pero idač í i de e a počte dvoj ý h vaze ěli ít, dík v šší itlivosti k o idač í u kratší délku života Tato část ašla této rešerši podporu. Druhá část týkají í se slože í e rá a r hlosti eta olis u, la větši ou studií v vrá e a. Me rá ů v šší r hlostí eta olis u spíše é ě e as e é oproti e rá á živoči hů po alejší eta olis e , se e ašla sig ifika t í korela e ož h potézou.
|
|
|
Physiological adaptations associated with body size and longevity in endothermic vertebrates
Pazdera, Lukáš ; Tomášek, Oldřich (advisor) ; Blažek, Radim (referee)
Abstact Lifespan is related to a number of physiological processes that are interconnected. Longevous species are assumed to have evolved certain physiological adaptations that slow down ageing rate and enable long lifespan. The aim of my thesis was to review physiological traits that has been hypothesised to be associated with lifespan, and to evaluate the empirical support for such hypotheses. Studies testing the association of these traits with body size has also been included in my thesis, as body size is known to be tightly related to lifespan. Traits that are reviewed in my thesis due to their hypothesised coevolution with lifespan are as follows: metabolic rate (i.e., a total amount of energy expended by the organism per unit of body mass and unit of time), oxidative stress resistance, telomere length and rate of telomere shortening and intensity of stress and immune responses. Key words: Lifespan, longevity, survival, reproduction, oxidative stress, free radicals, reactive oxygen and nitrogen species, metabnolic rate, immunity, antioxidants
|
guest ::
RSS feed.