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Undergraduate honors paper--Mount Holyoke College, 2008. Dept of Biological Sciences. / Includes bibliographical references (leaves 45-47).

Thesis (PhD)--Stellenbosch University, 1972. / ENGLISH ABSTRACT: See item for full text

Mini-dissertation submitted in partial compliance with the requirements for the Master's Degree in Technology: Homoeopathy, Durban University of Technology, 2007. / The purpose of this investigation was to determine the effect of Chamaeleo dilepis dilepis on healthy volunteers (provers), and to record the signs and symptoms produced, so that it may be prescribed to those suffering from similar symptoms as determined by the Law of Similars. A further aim of the investigation was to compare the materia medica of Chamaleo dilepis dilepis as determined by proving symptoms to those remedies yielding the highest numerical value and total number of rubrics on repertorisation of the proving symptoms of Chamaeleo dilepis dilepis. / M

Mini-dissertation submitted in partial compliance with the requirements for the Master's Degree in Technology: Homoeopathy, Durban University of Technology, 2007. / This study was conducted by administering Chamaeleo dilepis dilepis 30CH to healthy individuals with the aim of eliciting and documenting the resulting mental, emotional and physical symptomology. Chamaeleo dilepis dilepis was chosen as a substance based on it being indigenous to South Africa and as no other members of the Chamaeleonidae species have been proven / M

This dissertation has the object of re-examining the taxonomic status of the dwarf chameleons related to Bradypodion melanocephalum and Bradypodion caffrum from eastern South Africa. The historical context of previous taxonomic treatments is reviewed. The basis of the taxonomic interpretation was established after a review of available alternatives. Cladistic analysis is used to elucidate the relationships of the taxa. The number of separate taxa that can be distinguished has been increased by the revival of one previously described taxon, the discovery of heretofore unknown populations and by the detection of the composite nature of some of the previously described taxa. Diagnoses and descriptions of the taxa under review are provided along with a key to their identification. The geographic distribution of these Bradypodion taxa is reviewed in the context of present ecological parameters and in terms of the historical evolution of the study area. Comparison is made with the distributions of other taxa of plants. invertebrates and vertebrates occurring in the same general area. This appears to indicate a shared evolutionary history with a number of localised areas of endemicity. The conservation status of these Red Data Book and CITES-listed dwarf chameleons is discussed with discussion of threats and priorities for further action. The use of these dwarf chameleon species as indicators for the identification of endemic areas should have important implications for conservation strategies in eastern South Africa. This dissertation is not to be considered as a publication for the purposes of zoological nomenclature. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

abstract: Sexual and social signals have long been thought to play an important role in speciation and diversity; hence, investigations of intraspecific communication may lead to important insights regarding key processes of evolution. Though we have learned much about the control, function, and evolution of animal communication by studying several very common signal types, investigating rare classes of signals may provide new information about how and why animals communicate. My dissertation research focused on rapid physiological color change, a rare signal-type used by relatively few taxa. To answer longstanding questions about this rare class of signals, I employed novel methods to measure rapid color change signals of male veiled chameleons Chamaeleo calyptratus in real-time as seen by the intended conspecific receivers, as well as the associated behaviors of signalers and receivers. In the context of agonistic male-male interactions, I found that the brightness achieved by individual males and the speed of color change were the best predictors of aggression and fighting ability. Conversely, I found that rapid skin darkening serves as a signal of submission for male chameleons, reducing aggression from winners when displayed by losers. Additionally, my research revealed that the timing of maximum skin brightness and speed of brightening were the best predictors of maximum bite force and circulating testosterone levels, respectively. Together, these results indicated that different aspects of color change can communicate information about contest strategy, physiology, and performance ability. Lastly, when I experimentally manipulated the external appearance of chameleons, I found that "dishonestly" signaling individuals (i.e. those whose behavior did not match their manipulated color) received higher aggression from unpainted opponents. The increased aggression received by dishonest signalers suggests that social costs play an important role in maintaining the honesty of rapid color change signals in veiled chameleons. Though the color change abilities of chameleons have interested humans since the time of Aristotle, little was previously known about the signal content of such changes. Documenting the behavioral contexts and information content of these signals has provided an important first step in understanding the current function, underlying control mechanisms, and evolutionary origins of this rare signal type. / Dissertation/Thesis / Doctoral Dissertation Biology 2015

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: An important prerequisite for evolutionary change is variability in natural populations; however, when phenotypic and molecular rates of change differ, species delimitation is problematic. Such discordance has been identified in a recent radiation of dwarf chameleons (Bradypodion) from KwaZulu-Natal Province, South Africa. This radiation is comprised of several phenotypic forms, two of which have been classified taxonomically – Bradypodion melanocephalum and Bradypodion thamnobates. Early phylogenetic analysis did not support the forms primarily because geographic sampling and the set of molecular markers used were appropriate for detecting deep divergences and, therefore, less effective for understanding species boundaries within a recent radiation. In this radiation, the forms are allopatric, occupy different habitats, and vary in size and colouration, suggesting local adaptation and ecological speciation. To test this hypothesis, morphometric and habitat data were collected for each form to examine ecologically relevant morphological differences that reflect differential habitat use. Morphological differences were then associated with functional adaptations by testing locomotor performance and bite force. Next, fine-scale genetic sampling was used to examine lineage diversification using a combination of mitochondrial DNA and microsatellites. Spatial information was incorporated into these analyses to quantify the genetic effects of landscape barriers on genetic structure. Finally, ecological niche modelling was used to examine the abiotic factors involved in shaping the climatic niches of these chameleons, and to gain insight into their biogeographic history. Results show morphological distinctions between phenotypic forms, with corresponding differences in performance, indicating functional adaptations to habitats, which can be broadly classified as either open- or closed-canopy vegetation. Specifically, chameleons in open-canopy habitats have proportionally smaller forces and forefoot grip strengths. Varying degrees of sexual dimorphism were detected, with the closed-canopy forms being more dimorphic than the open-canopy forms. This suggests that sexual selection is the predominant force within the closed-canopy habitat, which are more protected from aerial predators, thereby enabling them to invest in dimorphic traits for communication; while, in open-canopy habitats, natural selection is the predominant force, ultimately enforcing their overall diminutive body size and constraining performance. Genetic structure was observed, with the mitochondrial DNA revealing three genetic clusters and the microsatellites revealing seven. This likely reflects the different mutation rates and modes of inheritance between these two markers. Three of the microsatellite clusters were supported by morphological and ecological data and should, therefore, be recognised as separate species. The remaining microsatellite clusters showed discordance with the ecomorphological data; however, given their genetic distinctiveness, they should be recognized as separate conservation units. The climatic niches of the three proposed species showed high to moderate levels of climatic stability, while the four proposed conservation units showed low climatic stability. These results indicate that this species complex is affected by both climatic niche conservatism and lability, which could explain the observed patterns of morphological and genetic diversity. In summary, these results support the hypothesis of ecological speciation within this radiation. / AFRIKAANSE OPSOMMING: 'n Belangrike voorvereiste vir evolusionêre verandering is variasie in natuurlike bevolkings, maar wanneer fenotipiese en molekulêre tempo van verandering verskil, is spesies definieering problematies. Sulke onenigheid is geïdentifiseer in ‘n onlangse radiasie van dwerg verkleurmannetjies (Bradypodion) van die KwaZulu-Natal Provinsie, Suid-Afrika. Hierdie radiasie bestaan uit verskeie fenotipiese vorms, waarvan twee taksonomies geklassifiseer is – Bradypodion melanocephalum en Bradypodion thamnobates. Vroeë filogenetiese analise het nie die vorms ondersteun nie, hoofsaaklik omdat geografiese steekproefneming en die stel van molekulêre merkers gebruik geskik was vir die opsporing van diep afwykings, en dus minder effektief is vir die begrip van spesies grense binne 'n onlangse radiasie. In hierdie radiasie is die vorms allopatries, beset verskillende habitatte, en wissel in grootte en kleur, wat dui op plaaslike aanpassing en ekologiese spesiasie. Om hierdie hipotese te toets, is morfometriese en habitat gegewens ingesamel vir elke vorm om sodoende ekologies relevante morfologiese verskille te ondersoek wat verskil in habitat gebruik reflekteer. Morfologiese verskille is geassosieer met funksionele aanpassings deur lokomotoriese prestasie en byt krag te toets. Volgende is fyn-skaal genetiese steekproefneming gebruik om afkoms diversifikasie met behulp van 'n kombinasie van mitochondriale DNS en mikrosatelliete ondersoek. Ruimtelike inligting is geinkorporeer in die ontleding om sodoende genetiese gevolge van landskap hindernisse op genetiese struktuur te kwantifiseer. Ten slotte, is ekologiese nis modelle gebruik om die abiotiese faktore wat betrokke is by die vorming van klimaat- nisse van hierdie verkleurmannetjie te ondersoek en om insig te verkry oor hul biografiese geskiedenis. Resultate toon morfologiese onderskeid tussen fenotipiese vorms, met saameenlopende verskille in prestasie, wat dui op funksionele aanpassings tot habitat, wat breedweg as oop- of geslote-kap plantegroei geklassifiseer kan word. Spesifiek verkleurmannetjies in oopkap habitatte het proporsioneel kleiner koppe en voete as hul geslote-kap eweknieë, en ooreenkomstig swakker byt krag en voorvoet greep. Wisselende vlakke van seksuele dimorfisme is vasgestel, met geslote-kap vorms wat meer dimorfies is as oop-kap vorms. Dit dui daarop dat seksuele seleksie die oorheersende krag in geslote-kap habitatte is, wat meer beskerm is teen vlieënde roofdiere, wat hulle in staat stel om te belê in dimorfiese eienskappe vir kommunikasie, terwyl in oop-kap habitatte, is natuurlike seleksie die oorheersende krag, wat uiteindelik kleiner liggaam grootte en beperkte prestasie afdwing. Genetiese struktuur is waargeneem, met die onthulling van drie genetiese groeperings gebasseer op mitochondriale DNS en sewe gebasseer op mikrosatelliete. Dit weerspieël waarskynlik die verskil in mutasie tempo en manier van erfenis tussen hierdie twee merkers. Drie van die mikrosatelliet groeperings is ondersteun deur morfologiese en ekologiese gegewens en moet dus erken word as aparte spesies. Die oorblywende mikrosatelliet groeperings dui op onenigheid met eko-morfologiese data, maar, gegewe hul genetiese eiesoortigheid, moet hulle erken word as afsonderlike bewarings eenhede. Die klimaat-nisse van die drie voorgestelde spesies het hoë tot matige vlakke van die klimaat stabiliteit, terwyl die vier voorgestelde bewarings eenhede lae klimaat stabiliteit het. Hierdie resultate dui daarop dat hierdie spesie kompleks beïnvloed word deur beide klimaat nis konserwatisme en stabiliteit, wat die waargenome patrone van morfologiese en genetiese diversiteit kan verduidelik. In opsomming, hierdie resultate ondersteun die hipotese van ekologiese spesiasie binne hierdie radiasie.

Dissertation (PhD)--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: South Africa, Lesotho and Swaziland are home to an endemic group of dwarf chameleons (Bradypodion). They are small, viviparous, insectivorous, arboreal lizards, found in a variety of vegetation types and climatic conditions. Previous work on Bradypodion pumilum suggests prolonged breeding and high fecundity which is very unusual for a viviparous lizard inhabiting a Mediterranean environment. It has been suggested that the alleged prolonged reproduction observed in B. pumilum may be a reproductive adaptation to life in a fire-prone habitat. In addition, Chamaesaura anguina a viviparous, arboreal grass lizard also occurs in the fire-frequent fynbos and exhibits an aseasonal female reproductive cycle with high clutch sizes; highly unusual for the Cordylidae. With the observation of two species both inhabiting a fire-driven environment and exhibiting aseasonal reproductive cycles with high fecundity, it was thought that this unpredictable environment may shape the reproductive strategies of animals inhabiting it. However, detailed reproductive data for B. pumilum were unavailable. The first aim was provide baseline reproductive data for B. pumilum and to discuss the reproductive strategy in relation to a fire-prone environment. To establish the significance of fire in the reproductive strategy of B. pumilum, reproductive data of other Bradypodion species, not inhabiting the fire-prone area was required. The second aim was to provide baseline reproductive data for Bradypodion with discussion on possible scenarios facilitating the evolution of dwarf chameleon reproduction. Bradypodion pumilum specimens were collected in monthly samples from Stellenbosch and Somerset West in the Western Cape, South Africa. Specimens of other Bradypodion species were obtained from South African museums. Data were collected for both sexes of Bradypodion, and sperm storage ability was investigated in B. pumilum. Bradypodion females all showed an aseasonal reproductive cycle with relatively high clutch sizes for their body size and the possibility of individual females producing multiple clutches per year. Male Bradypodion have sperm available the entire year round however, there appears to be an increase in sperm production in autumn and again in spring in B. pumilum. Elements of this bimodal pattern are seen in other Bradypodion species. Dwarf chameleons regardless of habitat and associated climatic conditions are thus able to reproduce through out the year. It has also been demonstrated in B. pumilum that both sexes are able to store sperm and it is expected that other Bradypodion species would posses this character. This type of reproductive strategy is highly unusual for viviparous, temperate-zone lizards. It is likely that the cooling of the climate due to the development of the Benguela current facilitated the transition to viviparity in Bradypodion. Bradypodion may be aseasonal reproducers for a number of reasons. They are of tropical ancestry, they relatively recently inhabited tropical forests, or fluctuations in climate may have caused this. Bradypodion most likely have a high reproductive output due to their intense vulnerability to predation as in other chameleon species. The proposed hypothesis that the unusual reproductive characteristics of B. pumilum (and possibly the ancestral Bradypodion) were due to inhabiting a fire-prone environment now appears an unlikely explanation. However, even if this extraordinary reproduction was not in direct response to fire, the strategy appears beneficial in this type of unpredictable environment. / AFRIKAANSE OPSOMMING: Suid-Afrika, Lesotho en Swaziland huisves ‘n endemiese groep van dwergverkleurmannetjies (Bradypodion). Hulle is klein, lewendbarende, insekvretende, arboreale akkedisse en word gevind in ‘n verskeidenheid van plantegroeitipes en klimaatsomstandighede. Vorige studies op Bradypodion pumilum dui op ‘n verlengde broeiseisoen en hoë fekunditeit, wat ongewoon is vir ‘n lewendbarende akkedis wat in ‘n Mediterreense omgewing voorkom. Daar is voorheen voorgestel dat die skynbare verlengde voortplanting in B. pumilum ‘n aanpassing tot oorlewing in hoogs brandvatbare habitat kan wees. Chamaesaura anguina is ook ‘n lewenbarende, arboreale akkedis wat in fynbos voorkom wat hoogs vatbaar is vir brande en groot werpsels produseer en ‘n aseisoenale voortplantingsiklus in wyfies toon; hierdie patroon is ongewoon vir lede van die Cordylidae. Met die waarneming dat twee species wat in ‘n brandvatbare omgewing voorkom albei aseisoenale voortplantingsiklusse en hoë fekunditeit toon, het die gedagte ontstaan dat hierdie onvoorspelbare omgewing die voortplantingstrategieë van diere wat daarin voorkom, bepaal. Gedetailleerde voortplantingsdata ontbreek egter vir B. pumilum. Die eerste doelstelling van die studie was dus om basisinligting te voorsien oor voortplanting by B. pumilum en om die voortplantingstrategie aan die hand van die brandvatbare omgewing te bespreek. Om die moontlike rol van brand in die vorming van die voortplantingstrategie van B. pumilum te ondersoek, is voortplantingsdata vir ander Bradypodion species wat nie in brandvatbare habitat voorkom nie, nodig. Die tweede doelstelling was dus om basisinligting oor voortplanting by Bradypodion in die breë in te samel, gevolg deur bespreking van moontlike scenarios in die evolusie van voortplanting by dwergverkleurmannetjies. Bradypodion pumilum eksemplare is maandeliks versamel te Stellenbosch en Somerset-wes in die Weskaap, Suid-Afrika. Eksemplare van ander Bradypodion species is vanaf Suid-Afrikaanse museums verky. Data is vir beide geslagte van Bradypodion versamel, en die vermoë tot spermstoring in B. pumilum bepaal. Bradypodion wyfies het almal ‘n aseisonale voortplantingsiklus getoon met relatief hoë werpselgroottes vir hul liggaamsgrootte en daar bestaan die moontlikheid dat individuele wyfies verskeie werpsels per jaar kan lewer. Bradypodion mannetjies produseer sperms dwarsdeur die hele jaar, maar daar blyk tog ‘n toename in spermstoring te wees in die herfs en weer in die lente in B. pumilum. Spore van hierdie bimodale patroon word in ander Bradypodion species gesien. Dwergverkleurmannetjies is dus instaat om dwardeur die jaar voort te plant, ongeag die habitat en geassosieerde klimaatsomstandighede. Daar is getoon dat beide geslagte van B. pumilum sperms kan stoor en daar word verwag dat ander Bradypodion species ook hierdie vermoë het. Hierdie tipe van voortplantingstrategie is ongewoon vir lewendbarende akkedisse van die gematigde sone. Dit is moontlik dat die ontwikkeling van ‘n koue klimaat weens die onstaan van die Benguela-stroom aanleiding gegee het tot die oorskakeling na lewendbarendheid in Bradypodion. Bradypodion mag aseisonale voortplanting toon vir ‘n aantal moontlike redes. Hulle is van tropiese oorsprong, het redelik onlangs tropiese woude betrek, of fluktuasies in klimaat kon ook die oorsaak wees. Bradypodion het waarskynlik hoë voortplantingsuitset omdat hulle besonder kwesbaar is vir predasie, soos dit die geval is by ander verkleurmannetjies. Die aanvanklike hipotese dat die ongewone voortplantingseienskappe van B. pumilum (en moontlik die voorvaderlike Bradypodion) ‘n gevolg is van lewe in ‘n hoogs brandvatbare omgewing, blyk nou ‘n onwaarskynlik te wees. Selfs as hierdie buitengewone voortplantingstrategie nie ‘n direkte gevolg van brandvatbaarheid is nie, blyk die strategie voordelig te wees vir oorlewing in hierdie onvoorspelbare omgewing.

Chameleons are scalar fields coming from modied gravity theories and can be possible explanations for Dark Energy. They cause a fifth force and have a screening mechanism which allows this force to avoid solar system constraints. In this thesis, astrophysical consequences of the potential presence of the chameleon field will be studied. More precisely, the difference between the hydrostatical and the weak lensing mass of galaxy clusters due to the effect of the chameleon fifth force is discussed.