Browsing by Subject "Lizards"
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Item A comparison of reproduction in two lizards, Cnemidophorus tigris marmoratus and Uta stansburiana stejnegeri(Texas Tech University, 1965-08) Hoddenbach, Gerard AndreNot availableItem A systematic and zoogeographic revision of the side-blotched lizards, genus Uta (family, Iguanidae)(Texas Tech University, 1967-08) Ballinger, Royce EugeneNot availableItem Anatomy of oviducts and sperm storage structures in lizards(Texas Tech University, 1965-08) Cuellar, OrlandoThis study was undertaken with the following objectives: (l) to conduct an exploratory survey for the presence of seminal receptacles in a variety of lizard species; (2) to test the fertilizing capacity of stored sperm in the seminal receptacles; (3) to make a detailed examination of the vaginal portion of the oviduct. Recent studies have directed much attention to discussions of the seminal receptacles and have neglected accurate description of the vagina where the receptacles have been found (Saint Girons, 1962; Fox, 1963). Earlier studies of the anatomy and histology of oviducts have been relatively superficial, particularly in descriptions of the vaginal segment (Brooks, 1905; Giersberg, 1922).Item Brazilian central Cerrado lizards in introduced Eucalyptus plantations : human mediated habitat disturbance effects from community diversity to population divergence(2012-05) Gainsbury, Alison Melissa; Pianka, Eric R.; Hillis, David M.; Bell, Christopher J.; Simpson, Beryl B.; Bolnick, Daniel I.Approximately two thirds of the world’s land is directly supporting human population contributing to an accumulation of disturbed habitats. This dissertation investigates the impact of human mediated habitat disturbance, in introduced Eucalyptus plantations, on community diversity and population divergence using Brazilian Cerrado lizards as a model. Data was collected along a gradient from undisturbed cerrado to disturbed Eucalyptus plantations. Community diversity differences and indicator species were identified. Furthermore, the role of phenotypic divergences were determined based on populations able to persist in disturbed habitats. Dispersal, food availability (body condition), competition and predation (caudal autotomy) were tested as potential mechanisms driving phenotypic divergences. Additionally, I investigated phylogenetic community structure differences between habitats to test for a phylogenetic signal to disturbance. The evidence showed community diversity indices were significantly lower in Eucalyptus plantations with a decrease along the cerrado– Eucalyptus gradient. Furthermore, 29 % of the Cerrado species suffered local extinctions in the disturbed habitat and of these 80 % are endemic species. One indicator species was identified for the disturbed habitat and seven species were identified for the undisturbed habitat. Species able to persist in both habitats demonstrated morphological trait divergences. These species showed short dispersal distances with only two individuals dispersing between habitats indicating a mechanism driving the observed phenotypic divergences. Another mechanism is body condition, which was higher in the disturbed habitats, reflecting increased food availability possibly due to the decreased abundances. Caudal autotomy showed no difference between the habitats indicating that competition and predation are not driving phenotypic divergences. Phylogenetic community structure demonstrated a phylogenetic signal to disturbance. The undisturbed habitat consists of communities with more closely related species compared to the disturbed habitat: indicating evolutionary forces such as habitat filtering as the stronger process structuring these communities. Whereas, disturbed communities are structured by ecological forces such as competition. This research provides information for the preservation and maintenance of the Cerrado biodiversity and has an even broader impact since habitat change caused by human activities touches a plethora of ecosystems.Item Ecological ontogeny in the lizard, Uta stansburiana stejnegeri(Texas Tech University, 1963-08) Woodard, Donald WoodsonNot availableItem Experimental hybridization between three populations of the lizard, Uta stansburiana(Texas Tech University, 1966-05) McKinney, Charles OranNot availableItem Reproduction in the little earless lizard, Holbrookia maculata maculata(Texas Tech University, 1965-08) Walker, Arden LeeNot availableItem Sexual, geographical, and individual variation in three Texas populations of the lizard Uta stansburiana stejnegeri(Texas Tech University, 1961-08) Knopf, Garry NolanNot availableItem Spermatogenesis of Anolis carolinensis(Texas Tech University, 1959-06) Pruitt, Celia RalstinA cytological study of the spermatogenesis of the American chameleon lizard, Anelis carolinensis, of the family Iguanidas, was made. Testicular tissue, taken from animals collected around Schriever, Louisiana (elevation 15 feet), was fixed in a modification of the Bouin-Allen fluid (corrected for altitude). Slides were prepared in the usual manner and stained in iron hemotoxylin. The diploid number of chromosomes was found to be thirty-four and the haploid number, seventeen. The prophase stages, as well as the metamorphosis of the spermatozoa, followed a general reptilian trend in development. Morphological evidence of sex-chromosomes was encountered. These chromosomes were most obvious in the side view of the primary spermatocyte cells. The sex-chromosome is bipartite and has spindle fiber attachments at one pole of the cell only.Item Spermatogenesis of the lizard, Sceloporus olivaceus(Texas Tech University, 1955-05) Wacasey, Jervis WinnNot availableItem Studies on the mating behavior of the side blotched lizard, Uta stansburiana(Texas Tech University, 1965-05) Ferguson, Gary WrightNOT AVAILABLEItem The ecology of the keeled earless lizard Holbrookia propinqua(Texas Tech University, 1973) Judd, Frank W.Not availableItem Variation in diet and habitat resource use in desert adapted lizards in Western Australia(2011-08) Goodyear, Stephen Edward; Pianka, Eric R.; Fowler, Norma L.Impacts of ecological competition are reduced when organisms play different roles in their environment. More individuals can survive on varied but finite sets of resources when organisms eat different kinds of prey, live in different places, or are active at different times. Species within an assemblage of small fossorial snakes have ecologies that vary mostly by diet. Different species eat very different things. Species live in different habitats on sand ridges, but the differences are less dramatic than in diet. Disparity in resource use typically varies the most according to species, so that individuals of the same species are more similar to each other than they are to individuals of other species. However, variation exists in resource use within species over time and space. Wide variation exists in dietary resource use in four well-sampled species of comb-eared skinks. However, where species occur at the same study site there are clear distinctions in resource use between species despite the wide variation in diets observed between individuals of the same species. Additionally, strict ecological distances in diet between species are maintained during five censuses that were conducted over a 16-year period. These results illustrate the basic ecological principals of fundamental and realized niches. Here, individuals ate many different food items and species have the potential to overlap in diet but that overlap is reduced because of realized ecological boundaries between species within a single place and time, which result in decreased competition for resources.