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Reproductive modes in large Branchiopoda (Crustacea) and their effect on genetic structure of populations
Šimková, Zuzana ; Sacherová, Veronika (advisor) ; Straková, Barbora (referee)
This bachelor's thesis focuses on the influence of the reproductive systems of four groups of so-called large branchiopods (Crustacea: Branchiopoda) on genetic variability in their populations. The groups include the orders of fairy shrimp (Anostraca), tadpole shrimp (Notostraca), clam shrimp (Spinicaudata), and conchostracans (Laevicaudata). This thesis primarily examines the populations in Europe. Reproductive strategies are one of the key factors that influence the genetic variability of populations. Other factors include historical events such as the breakup of the supercontinents Gondwana and Pangea and the last ice age, along with its associated processes (such as the colonization of new habitats after the end of the last ice age, etc.) The most genetically variable populations in Europe are gonochoristic (Branchipus schaefferi, Phallocryptus spinosa, Triops mauritanicus, Leptestheria dahalacensis, and Lynceus brachyurus), followed by populations with other reproductive systems. Based on current knowledge, some gonochoristic species and species utilizing a different reproductive system are divided into multiple genetic lineages. Depending on the historical processes, these lineages were most likely separated before the last ice age. Therefore, the current geographical distribution of lineages...
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How many times and why did (not) hermaphroditism evolve in Deuterostomia?
Tribulová, Lucia ; Vukićová, Jasna (advisor) ; Choleva, Lukáš (referee)
The Deuterostomia are large and highly diversified group that also includes vertebrates. Most species are gonochorists and only a small percentage are hermaphrodites. The predominantly hermaphroditic group is the tunicates, and among the vertebrates, hermaphrodites are known mainly in teleost fishes. In other groups, only a few hermaphroditic species are known. According to general ecological-evolutionary models, hermaphroditism arises in environments where there is a low abundance of individuals ("low density model") or when the reproductive value of one sex is favoured with larger size ("size advantage model"). Deuterostomia are an excellent model group for testing these models; teleost fishes, in particular, abounding in a variety of social and reproductive systems, are well suited for testing the "size advantage" model. The aim of this work is to determine from the available literature how many times and in which groups hermaphroditism has occurred in Deuterostomia, why it has evolved in these groups, and whether the occurrence of hermaphroditism fits general ecological-evolutionary models. Key words: hermaphroditism, deuterostomia, protandry, protogyny, simultaneous hermaphroditism
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