11 research outputs found
V Jornadas de InvestigaciĂłn de la Facultad de Ciencia y TecnologĂa. 2016
171 p.I. Abstracts. Ahozko komunikazioak / Comunicaciones orales:
1. Biozientziak: Alderdi Molekularrak / Biociencias: Aspectos moleculares.
2. Biozientziak: Ingurune Alderdiak / Biociencias: Aspectos Ambientales.
3. Fisika eta Ingenieritza Elektronika / FĂsica e IngenierĂa ElectrĂłnica.
4. GeologĂa / GeologĂa.
5. Matematika / MatemĂĄticas.
6. Kimika / QuĂmica.
7. Ingenieritza Kimikoa eta Kimika / IngenierĂa QuĂmica y QuĂmica.
II. Abstracts. Idatzizko Komunikazioak (Posterrak) / Comunicaciones escritas (PĂłsters):
1. Biozientziak / Biociencias.
2. Fisika eta Ingenieritza Elektronika / FĂsica e IngenierĂa ElectrĂłnica.
3. Geologia / Geologia.
4. Matematika / MatemĂĄticas.
5. Kimika / QuĂmica.
6. Ingenieritza Kimikoa / IngenierĂa QuĂmica
V Jornadas de InvestigaciĂłn de la Facultad de Ciencia y TecnologĂa. 2016
171 p.I. Abstracts. Ahozko komunikazioak / Comunicaciones orales:
1. Biozientziak: Alderdi Molekularrak / Biociencias: Aspectos moleculares.
2. Biozientziak: Ingurune Alderdiak / Biociencias: Aspectos Ambientales.
3. Fisika eta Ingenieritza Elektronika / FĂsica e IngenierĂa ElectrĂłnica.
4. GeologĂa / GeologĂa.
5. Matematika / MatemĂĄticas.
6. Kimika / QuĂmica.
7. Ingenieritza Kimikoa eta Kimika / IngenierĂa QuĂmica y QuĂmica.
II. Abstracts. Idatzizko Komunikazioak (Posterrak) / Comunicaciones escritas (PĂłsters):
1. Biozientziak / Biociencias.
2. Fisika eta Ingenieritza Elektronika / FĂsica e IngenierĂa ElectrĂłnica.
3. Geologia / Geologia.
4. Matematika / MatemĂĄticas.
5. Kimika / QuĂmica.
6. Ingenieritza Kimikoa / IngenierĂa QuĂmica
Comparative ecology and phylogeography in east African cichild fishes
Since almost two decades speciation outbursts, so-called adaptive radiations, have been put forward as a major reason for a large portion of the bio-diversity we see today. Adaptive radiations are indisputably very complex processes with many factors to consider. They are, however, not separable from the concept of ecological speciation by the means of natural selection. Hence the concept of convergent evolution, which states that different organisms independently evolve similar morphological or behavioral traits as a result of similar ecological selection regimes, was put forward as an essential indicator of the âadaptivenessâ of respective species differences and/or similarities. In the exceptionally species rich and eco-morphologically highly diverse assemblages of the East African Rift lakes, the paradox was put forward that competitive ecological exclusion of converging species seems to require a temporal and special separation (allopatry) of the different lineages in order for them to coexist. Recent phylogenetic framework and molecular dating seem to indicate though that in fact many lineages formed very rapidly thus not allowing the avoidance of competitive exclusion.
These are questions addressed in the first part of my thesis (âComparative ecologyâ) consisting of two Chapters. 1: âConvergent evolution within an adaptive radiation of cichlid fishesâ where we investigated ecologically based convergence within the Lake Tanganyika cichlid radiation and 2. âThe ecological and genetic basis of convergent thick-lipped phenotypes in cichlid fishesâ where we investigated the convergent occurrence of a conspicuous trait which is thought to be highly adaptive, the thick lipped phenotype of cichlid fishes.
Considering the strong connectivity of convergent evolution with the ecological properties of a habitat mediated by natural selection it is apparently crucial to study ecological parameters of habitats connected by convergent phenotypes which we did in Chapter 3: "Depth-dependent abundance of Midas Cichlid fish (Amphilophus spp.) in two Nicaraguan crater lakes". Here we characterised effective population sizes by means of transect methods in order to compare two lakes exhibiting convergent phenotypes.
In a second part (âPhylogeographyâ) I combine different studies dealing with a combination of distributional patterns, patterns of phylogenetic relationships and ecological factors of east African riverine cichlids since they have become increasingly important in the understanding of large-scale relations of African cichlid fishes. In Chapter 4: âBack to Tanganyika: a case of a recent immigration into a species flock of East African cichlid fishesâ we investigate a recently discovered dispersal event of a modern cichlid lineage (Haplochromis spp.) across major watershed barriers in Eastern Africa. In Chapter 5: âDivergence between lake and stream habitats in an East African cichlid fishâ we investigate the degree of ecological divergence of a riverine cichlid species, which also occurs in pure lake habitats (Astatotilapia burtoni). In Chapter 6: âAdmixture between divergent mitochondrial lineages and greater phenotypic variation in a basal haplochromine cichlid fish from Lake Chila, Zambiaâ we investigate the phylogeographic history of a basal haplochormine clade (genus: Pseudocrenilabrus).
Morphological diversity within natural populations is a crucial prerequisite for natural selection to act on and to enable ecological adaptive evolution. A special case of such morphological variation, the mouth asymmetry of scale eating cichlid fish of Lake Tanganyika, was the main topic of the third part of my thesis (âAsymmetrical Polymorphismâ) and Chapter 7: âA field based assessment of attack strategies and feeding success in the scale eating cichlid fish Perissodus microlepis (Perciformes)â