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MSCAGR (Animal Science) / Department of Animal Science / In order to realize many of the potential advantages of AI, storage of semen is necessary. Semen storage is only possible using a system that decreases and/or halts the metabolic processes of the spermatozoa, allowing no significant loss of fertility. Numerous factors affect the success of spermatozoa storage. This study was designed to compare the effects of egg yolk, soybean milk and coconut water in Tris extender using different storage methods for Nguni bull spermatozoa storage. Bull semen was collected from two adult Nguni bulls approximately four years old and kept under similar managerial conditions. Using electro-ejaculator, semen was collected from each bull into a graduated semen collection tube. Macroscopically evaluation of the sample was performed immediately after collection. Only the semen free from contamination was processed. The kinetic properties namely: total spermatozoa motility, and progressive spermatozoa motility were analysed using CASA. Semen sample was stained and spermatozoa morphology and vitality also analysed using CASA. The extended semen was then split into three groups. The first group was stored at room temperature (25 °C). The second group was cooled to 4 °C and stored in the refrigerator. The third group was also cooled to 4 °C for 2 h in the refrigerator, then held in LN2 vapour 5 cm above the surface of LN2 at ~ -80 °C for 10 min and then plunged into LN2 for storage at -196 °C. Different colours of straws and plugging powder were used for identifying each extender. After 3 days of storage at room temperature, in the refrigerator and in LN2, the extended semen was split into three portions and assayed for kinetic properties using the first portion. The second portion was assayed for spermatozoa morphology and the third portion for spermatozoa vitality. The results from the fresh semen extended with all three extenders (TEYE, SBME and COWE), and analysed immediately after dilution at room temperature (25 ºC), showed no significant difference (P > 0.05) in the mean values of the kinetic and morphologic properties and viability, on spermatozoa TM, PM, AR, AT, CT; BT and LS. After three days of storage, there was no significant difference (P > 0.05) in the kinetic morphologic properties and viability of semen stored at room and refrigeration temperature regardless of the extender in use. There were, however, significant differences (P < 0.05) in the TM, PM, AR and DL of the frozen semen samples. For the short storage period of semen used for AI, from this study, it is recommended that semen should be kept at room or refrigeration temperature regardless of the three extenders used. However, for long storage of frozen semen TEYE is recommended. The egg yolk-based extender provided greater preservation of motility and bull spermatozoa integrity during the freezing process than did SBME and COWE.

In addition to proving an excellent source of nutrients, eggs are used in the food, cosmetic, and biotechnology industries for their rheological and bioactive properties. Much of the potential for the added value is in individual components of the egg, rather than the whole egg. At low speed centrifugation, yolk separates into two distinct fractions—granules and plasma. It is becoming increasingly popular in the industry to remove the plasma fraction of the egg yolk to use for its livetins, particularly immunoglobulin Y, leaving behind a granule by-product (“yellow cake”). Previous research has shown potential added-value from the granule fraction, especially from its phosvitin and phospholipids. Granules are protein aggregates with complexes of phosvitin and high density lipoproteins linked by phosphocalcic bridges. In their native form, the proteins are mostly insoluble, however previous studies have shown the links can be broken by alterations in pH, ionic strength, and mechanical treatments. This thesis project seeks to find potential uses for the egg yolk by product after the removal of the livetin fraction by means of further fractionation with mechanical treatment (filtration). Two variables were tested to extract more proteins from the yellow cake. Salt was added to 10% solids solution of yellow cake in water before filtration at four different NaCl levels: 0%, .05%, 1%, and 2.5%. Additionally pH was tested at four different levels: 4.6, 4.8, 5.0, 5.2. The samples were also tested for antibacterial properties against Escherichia v coli with a minimum inhibitory concentration assay (MIC). Analysis with BCA showed salt concentration had a significant effect on the yield of protein. The highest concentration of salt tested, 2.5%, had the highest protein yield. Additionally, SDS PAGE showed 2.5% salt had the most unique protein bands. This could be to the disruption of the phosphocalcic links between the phosvitin and HDL by NaCl, allowing the protein to solubilize. pH did not have a significant effect on the yield or types of proteins in the range tested in this experiment. There is no conclusive evidence of antibacterial properties against E. coli from the protein extract. The MIC assay had growth show up in all wells with the protein extract, however there was a visible decrease in turbidity with higher concentration of the protein extract. This could mean that the protein extract does have some antibacterial properties, but needs testing at higher concentrations or with isolated proteins/peptides. The SDS-PAGE revealed bands showing phosvitin present, which has known antibacterial properties. Overall, improvements to the methods for further protein extraction from egg yolk by-products will help lead the industry to finding novel uses and product applications.

We review morphological features of the amniote egg and embryos in a comparative phylogenetic framework, including all major clades of extant vertebrates. We discuss 40 characters that are relevant for an analysis of the evolutionary history of the vertebrate egg. Special attention is given to the morphology of the cellular yolk sac, the eggshell, and extraembryonic membranes. Many features that are typically assigned to amniotes, such as a large yolk sac, delayed egg deposition, and terrestrial reproduction have evolved independently and convergently in numerous clades of vertebrates. We use phylogenetic character mapping and ancestral character state reconstruction as tools to recognize sequence, order, and patterns of morphological evolution and deduce a hypothesis of the evolutionary history of the amniote egg. Besides amnion and chorioallantois, amniotes ancestrally possess copulatory organs (secondarily reduced in most birds), internal fertilization, and delayed deposition of eggs that contain an embryo in the primitive streak or early somite stage. Except for the amnion, chorioallantois, and amniote type of eggshell, these features evolved convergently in almost all major clades of aquatic vertebrates possibly in response to selective factors such as egg predation, hostile environmental conditions for egg development, or to adjust hatching of young to favorable season. A functionally important feature of the amnion membrane is its myogenic contractility that moves the (early) embryo and prevents adhering of the growing embryo to extraembryonic materials. This function of the amnion membrane and the liquid-filled amnion cavity may have evolved under the requirements of delayed deposition of eggs that contain developing embryos. The chorioallantois is a temporary embryonic exchange organ that supports embryonic development. A possible evolutionary scenario is that the amniote egg presents an exaptation that paved the evolutionary pathway for reproduction on land. As shown by numerous examples from anamniotes, reproduction on land has occurred multiple times among vertebrates—the amniote egg presenting one “solution” that enabled the conquest of land for reproduction.

In 1926, the German biologist Johanna (Hanni) Hrabowski published a study of the morphology and development of the fetal placenta in lizards that has proven to be of historical importance. Her anatomical descriptions and interpretations identified developmental patterns that differ from other amniotes – features now recognized as unique attributes of squamate (lizards and snakes) development. Her 1926 monograph presented the first histological comparison of fetal membranes in closely-related oviparous and viviparous reptiles, thereby establishing a comparative framework for understanding placental specializations for viviparity. Hrabowski reported that yolk sac development did not differ between oviparous and viviparous species. The novel, shared components of yolk sac development she identified are now recognized as the foundation for the unique yolk sac placenta of reptiles, the omphaloplacenta. In addition, Hrabowski's extensive ontogenetic sampling and the detail and accuracy of her anatomical descriptions set high standards for subsequent studies of comparative evolutionary embryology.

The F-strain of Mycoplasma gallisepticum (FMG) is commonly used in vaccination programs to displace infections by more virulent natural or wild type Mycoplasma gallisepticum strains. However, a better understanding of the mechanisms responsible for altered egg production (EP) and egg quality in commercial layers infected with FMG is important, as these alterations can cause economic loss to the United States layer industry. This study was designed to examine potential mechanism(s) responsible for alterations in EP and egg quality by FMG-inoculation. The effects of FMG on production parameters and physiological characteristics of commercial laying hens were evaluated. In isolation units, 12 wk FMG inoculation delayed onset of lay approximately one wk, decreased overall EP, and decreased EP 34 wk post-inoculation. A 12 wk FMG inoculation also resulted in a higher incidence of fatty liver hemorrhagic syndrome, ovarian follicular regression, and decreased isthmal and vaginal proportions of the reproductive tract. Ovarian regression may be related to retarded production (liver), transport (blood), and/or uptake (ovary) of yolk particles. Changes in blood characteristics (i.e. lipid composition) with FMG colonization of the liver may become manifest through changes in egg constituents. As evidenced through changes in the relative weights of various reproductive organs, colonization of these organs by FMG, in addition to the liver, may also be a cause of the effects observed on EP. Increases in hematocrit, serum triglycerides, and plasma protein between 8 and 10 wk post FMG-inoculation, suggest that the initial weeks of EP are stressful. Post-peak decreases in these same variables suggest a more chronic inhibition on lipid and protein synthesis in the liver. Decreased blood lipid concentration may be directly responsible for the reductions in yolk lipid, cholesterol, and fatty acid deposition in 12 wk FMG-inoculated hens. Dual adverse effects in the caged layer facility on feed conversion and egg mass were realized in 22 wk FMG-inoculated birds. In contrast, a 12 wk FMG inoculation delayed onset of lay without a loss in total EP or egg mass. Therefore, inoculation with FMG at 12 wk is more practical and cost effective. Higher degrees of physiological stress experienced by hens in a caged layer facility may exacerbate the effects of FMG inoculation seen in the isolation units. These data demonstrate that alterations in performance and egg characteristics of commercial layers inoculated with FMG at either 12 or 22 wk of age and housed in either isolation units or caged layer facilities are related to mutual functional disturbances in the blood, liver, ovary, and oviduct without concomitant intestinal changes.

Average global ocean temperatures and the frequency and intensity of marine heat waves have been increasing over the last century. Temperature plays a critical role in defining the geographical range of the majority of marine species. Some species may respond to ocean warming trends by shifting their latitudinal and depth ranges, while others may be able to cope with changes in temperature through phenotypic plasticity and local adaptations. If a species is unable to shift its distribution or has limited thermal plasticity, it may face severe population declines or local extinction. Therefore, describing thermal tolerance limits is a useful tool for predicting how a given species will respond to ocean warming. Due to its commercial importance, sablefish (Anoplopoma fimbria) is a fish species of particular interest in British Columbia. Sablefish are semi-demersal and spawn along the continental slopes of the Pacific coast from California to Alaska. Their various life history stages occupy different depth strata and thus experience substantially different environments with respect to temperature (as well as salinity, oxygen, etc.). Adult sablefish spawn at depths that exceed 300 m and embryos sink to depths of ~1,000 m after fertilization. Embryos hatch into yolk-sac larvae until they become mobile at the post-yolk-sac larvae stage. The latter migrate to near-surface waters (<3 m) at which temperatures are approximately 12-15°C in the late spring. Heart rate is a temperature-dependent performance measure and has been used to gain insight into the thermal tolerance of many adult fishes. However, few studies have used this approach with the early life stages of fishes such as embryos and yolk-sac larvae (YSL). The purpose of this study was to assess whether sablefish embryos and YSL have the potential for cardiac acclimation by examining changes in their thermal tolerance limits when incubated at temperatures outside of what they experience in a natural setting (~5°C). Cardiac performance was assessed during an acute temperature challenge from 2.0° to 12.0°C in increments of 1.0°C (at a rate of 1°C 40 min-1) for individuals incubated at 3.0°C, 5.0°C (control), and 7.0°C. Embryos were video recorded at each 1.0°C increment and videos were viewed at a later date to determine heart rate at each temperature. This study attempted to use temperature breakpoint analysis, commonly used in studies of adults, on these early life stages to assess cardiac performance. It was hypothesized that sablefish embryos and yolk-sac larvae incubated at warmer temperatures would have a higher thermal tolerance than sablefish embryos and YSL incubated at colder temperatures, as seen in other fish species. There was some degree of thermal compensation of cardiac function with temperature in sablefish embryos and YSL as mean heart rate increased with incubation temperature throughout acute warming. YSL had consistently higher mean heart rate values at any given temperature of the acute temperature challenge when compared to embryos incubated at the same temperature. TAR is the temperature at which the heart first becomes arrhythmic is considered a sub-lethal index because the organism is expected to experience cardiac collapse soon after. TAR was reached for 100% of embryos incubated at 3.0°C at an average temperature of 8.6 ± 1.0°C. In contrast, only 18% and 33% of embryos incubated at 5.0° and 7.0°C exhibited arrhythmia (mean TAR were 9.0 ± 3.0 and 8.5± 1.5°C, respectively). The lower thermal limit for embryos incubated at 7.0°C was likely near 1.0°C, which was determined during preliminary testing. Neither the upper or lower limits were reached for YSL during the acute temperature challenge. No mortalities were observed during any acute temperature challenges. Overall percent mortality throughout the entirety of the experiment could not be determined due to limitations in the experimental setup and reduced staff working on this project due to COVID-19 safety protocols. This study is also the first to investigate whether transporting sablefish embryos from a hatchery to a research facility at different stages of development had an effect on their cardiac performance during acute warming. Embryos were transported in a cooler from the sablefish hatchery on Salt Spring Island to UVic via ferry and vehicular transport. Time of transportation did not significantly change the temperature at which heart rate reaches its maximum or TAR. There was also consistent overlap in mean heart rate ± standard error at each temperature of the acute temperature challenge between these two groups. Therefore, there appears to be no indication that transportation affected the heart rate response of sablefish embryos when incubated at the same temperature. However, future studies may want to confirm this by identifying and comparing other breakpoint temperatures that characterize physiological performance. Determining whether transportation has effects on cardiac performance may be of interest to other researchers who need to transport fish embryos from the field to the laboratory. Heart rate measurements during an acute temperature challenge of sablefish embryos and yolk-sac larvae (YSL) incubated at various temperatures provided initial insight to their overall success in a warming climate. Currently, it is projected that waters at depths of 1,000 m will warm on average by less than a degree by the end of the 21st century. The results of this study suggest that the early life stages of sablefish may not be exposed to critical temperatures in the near future, but future impacts on overall physiological decline remain unknown. The novel data presented here lay the groundwork for future researchers to continue to characterize the thermal tolerances of the early life stages of sablefish, and the likely response of this important species to ocean warming. / Graduate

The small intestine and yolk sac (YS) are important organs for nutrient absorption and innate immunity in chickens during the post-hatch or prehatch periods. These organs share a similar structure of epithelial cell-lined villi with tight junctions between adjacent cells. Probiotics have been reported to improve chicken growth performance and gut health including promotion of intestinal morphology. However, there are few studies that show the effect of probiotics on ontogeny of intestinal epithelial cells and antimicrobial peptides, or intestinal integrity in young healthy chicks. Heat stress during incubation was shown to increase mortality and decrease hatchability of chicks, while no studies have investigated the effect of heat stress on the integrity of the YS, which might be related to hatching performance. There were four studies conducted in this research: 1) a comparison of the effect of two probiotics on the ontogeny of small intestinal epithelial cells in young chicks; 2) the effect of two probiotics on mRNA abundance of tight junction proteins in the small intestine of young chicks; 3) the effect of high incubation temperature on mRNA abundance of tight junction proteins in the YS of broiler embryos; and 4) comparison of avian defense peptide mRNA abundance in the YS of broilers and layers. In study 1, Probiotics transiently decreased body weight gain (BWG) from day 2 to day 4, but did not affect body weight (BW) from day 2 to day 8, and small intestinal weight and intestinal morphology from day 2 to day 6. Probiotics did not affect marker gene expression of intestinal stem cells (Olfm4) and goblet cells (Muc2) in all small intestinal segments, but did increase expression of a marker gene of proliferating cells (Ki67), and decreased an antimicrobial peptide (liver-enriched antimicrobial peptide 2, LEAP2) in the jejunum at day 4. Probiotic 1 decreased PepT1, a marker of enterocytes in the duodenum at day 4. These results suggest that probiotics did not improve growth performance and intestinal morphology in young healthy chicks, but temporarily promoted intestinal epithelial cell proliferation and decreased LEAP2 antimicrobial peptide expression in the jejunum. In situ hybridization (ISH) showed that Ki67+ proliferating cells were mainly located in the crypt region and the blood vessels of villi. In study 2, Probiotic supplementation to newly hatched chicks for less than one week did not affect mRNA abundance of the tight junction proteins in the small intestine. Occludin (OCLN) mRNA, which was detected by ISH to be expressed in intestinal epithelial cells in both the villus and crypt regions, was greater in the duodenum of female chicks than males. In study 3, high incubation temperature starting from embryonic day 12 (E12) affected mRNA abundance of the tight junction proteins in the YS, including increased zonula occluden 1 (ZO1) at E13, increased junctional adhesion molecule A (JAMA) and heat shock protein 90 (HSP90) at E17, but decreased tight junction protein JAMA at E19 and OCLN at day of hatch (DOH). These results showed that the YS tight junction proteins were increased by short term heat exposure but decreased by long term heat exposure. In study 4, the expression of avian β defensin 10 (AvBD10), CATHs and toll-like receptors in the YS was examined. Toll-like receptors were highly expressed in the YS at early incubation stages (E7), while CATHs showed a peak expression from E9 to E13, which was similar to the expression pattern of AvBD10. CATHs and AvBD10 mRNA temporal expression patterns were similar in broilers and layers, while their expression levels were different. Layers, especially brown layers, had greater mRNA abundance for antimicrobial peptides such as AvBD10, CATH1, and CATH2 in the YS. These results demonstrate that the antimicrobial peptide temporal expression patterns in the YS are not affected by breed, but their expression levels are affected by breed. In summary, the small intestine and the YS are essential for nutrient uptake, innate immunity, and maintenance of integrity. The ontogeny of intestinal epithelial cells, such as proliferating cells can be modulated by probiotic supplementation. Similar to the small intestine, the YS can also express tight junction proteins, which can be affected by high incubation temperature. Antimicrobial peptide expression in the intestine of healthy young chicks is also transiently decreased by probiotic supplements. Avian defensin and cathelicidin expression patterns in the YS were not affected by breed. / Doctor of Philosophy / The small intestine and yolk sac are important organs for nutrient absorption in hatched chicks or embryonic chicks. These organs also serve as a barrier to prevent pathogens from entering the blood circulation. Intestinal epithelial cells along the villi renew rapidly by proliferation and differentiation. In this research, probiotics which are also known as direct fed microbials temporarily increased expression of the proliferating cell marker Ki67 in the jejunum of healthy young chicks, which suggests that probiotics promote intestinal epithelial cell proliferation. However, probiotics transiently decreased expression of an antimicrobial peptide, which may reduce immune protection in the gut. The yolk sac can also express tight junction proteins. The expression of tight junction proteins was affected by elevated incubation temperature in broiler embryos, which might be related to low hatchability of eggs exposed to heat stress. Avian defense peptides and pathogen recognition receptors were expressed in the YS, which implied that the yolk sac contained an innate immune function. The expression pattern of avian defense peptides was affected by breed (broilers and layers), while the expression level of avian defense peptides was greater in layers than broilers. In summary, the small intestine and the yolk sac are multifunctional organs. Their cell composition, structural integrity, and secretion of antimicrobial peptides can be affected by environmental factors, such as probiotic supplementation or high incubation temperature.

The incubation period is crucial for development and overall quality of a chick. The selection for fast growing broilers has allowed the birds to reach market weight at a faster rate making the incubation period a larger portion of a broiler's life. A faster growth rate can lead to the release of more metabolic heat inside of the egg toward the second half of incubation because the embryo shifts to a homeothermic state. More heat being released into the incubator can cause the incubation temperature to rise if the incubator is not electronically regulated or cannot be ventilated properly due to malfunction. A high incubation temperature can impact the hatchability, growth, and development of the chick. This thesis provides a more in-depth analysis of the effects of high incubation temperature (37.5°C versus 39.5°C) on the developing small intestine and yolk sac, which provide the chick with nutrients posthatch and during embryogenesis. Studying these organs and mechanisms occurring during this time could potentially indicate why chicks from eggs subjected to a higher incubation temperature are not developing and growing properly. Chicks from eggs incubated at a higher temperature had lower body weights, lower hatchability and lower villus height in the duodenum, jejunum, and ileum. There were also differences seen in the depth of the crypt, which is the site for stem cells. Chicks from eggs incubated at a higher temperature had a lower crypt depth in the duodenum and jejunum. There was no difference in the expression of the intestinal stem cell marker olfactomedin 4 (Olfm4) and mucin 2, which is secreted by goblet cells and forms mucus. In the yolk sac, heat shock proteins (HSP) 70 and 90 were elevated at embryonic day 15, and HSP90 still remained elevated at embryonic day 17. Chicks from eggs incubated at a higher temperature showed greater expression of peptide transporter 1 and avian beta-defensin 10 mRNA at embryonic day 13. Even though small intestinal morphology was impacted early posthatch and expression of genes in the yolk sac were elevated at embryonic day 13, there does not seem to be a long-lasting effect on the development of the small intestine or the yolk sac. It is still important to study the impact of the incubation environment to understand the development and growth of the chicks and how different incubation factors can impact the overall hatchability and health of the chick. / Master of Science / The incubation period is crucial for development and overall quality of a chick. The selection for fast growing broilers has allowed the birds to reach market weight at a faster rate making the incubation period a larger portion of a broiler’s life. A faster growth rate can lead to the release of more metabolic heat inside of the egg toward the second half of incubation because the embryo shifts to a homeothermic state. More heat being released into the incubator can cause the incubation temperature to rise if the incubator is not electronically regulated or cannot be ventilated properly due to malfunction. A high incubation temperature can impact the hatchability, growth, and development of the chick. This thesis provides a more in-depth analysis of the effects of high incubation temperature (37.5°C versus 39.5°C) on the developing small intestine and yolk sac, which provide the chick with nutrients posthatch and during embryogenesis. Studying these organs and mechanisms occurring during this time could potentially indicate why chicks from eggs subjected to a higher incubation temperature are not developing and growing properly. Chicks from eggs incubated at a higher temperature had lower body weights, lower hatchability and lower villus height in the duodenum, jejunum, and ileum. There were also differences seen in the depth of the crypt, which is the site for stem cells. Chicks from eggs incubated at a higher temperature had a lower crypt depth in the duodenum and jejunum. There was no difference in the expression of the intestinal stem cell marker olfactomedin 4 (Olfm4) and mucin 2, which is secreted by goblet cells and forms mucus. In the yolk sac, heat shock proteins (HSP) 70 and 90 were elevated at embryonic day 15, and HSP90 still remained elevated at embryonic day 17. Chicks from eggs incubated at a higher temperature showed greater expression of peptide transporter 1 and avian beta-defensin 10 mRNA at embryonic day 13. Even though small intestinal morphology was impacted early posthatch and expression of genes in the yolk sac were elevated at embryonic day 13, there does not seem to be a long-lasting effect on the development of the small intestine or the yolk sac. It is still important to study the impact of the incubation environment to understand the development and growth of the chicks and how different incubation factors can impact the overall hatchability and health of the chick.

The phenotypes of hatchling reptiles are influenced by the environmental conditions that embryos experience during incubation, by yolk invested into the egg, and by the genetic contributions of the parents. Phenotypic traits are influenced by these factors in ways that potentially affect the fitness of hatchlings. The physical conditions that embryos experience within the nest affects development, hatching success, and hatchling phenotypes. Thus, the nest site that a female selects can influence the survival of her offspring as well as her overall fitness. In Chapter 1, I addressed this issue through a nest site selection experiment designed to determine the substrate temperature and moisture conditions that female eastern fence lizards (Sceloporus undulatus) select when provided a range of conditions from which to choose. In general, I found that females selected nest sites with conditions that yield high hatching success. In Chapter two, I investigated the relative contributions of incubation moisture conditions, maternal yolk investment, and clutch (genotype) to variation in hatchling phenotypes and survival under field conditions. Eggs from 28 clutches were distributed among two moisture treatments; wet (-150 kPa) and dry (-530 kPa). In another treatment, yolk was removed from eggs to determine the affect of yolk quantity on hatchling phenotypes. After hatching, several phenotypic traits (mass, snout-vent length, tail length, body shape, thermal preference, running speed, desiccation rate, and growth rate) were measured. Hatchlings were subsequently marked and released at a field site in southwest Virginia. Hatchlings were recaptured twice weekly prior to winter and the following spring to monitor growth and survival. I found that incubation moisture and yolk removal affected only hatchling body size; individuals from the dry and yolk removed treatments were smaller in body size than those from the wet treatment. However, clutch was the most important source of phenotypic variation; all phenotypes were affected by clutch. Significant clutch effects suggested the possibility that phenotypic variation had at least some genetic basis. In the field, survival was not affected by incubation moisture and yolk removal, and overall survival was not associated with hatchling body size. Survivors and nonsurvivors differed only in growth rate in the field and running speed measured in the laboratory. Survivors ran faster and grew more slowly than nonsurvivors. To examine the association of clutch with survival, I used clutch mean values to look at the relationship between phenotype and survival. Clutches that produced relatively slow growing individuals and fast runners had higher survival rates than clutches that produced relatively rapid growing individuals and slow runners. In order to grow rapidly, an individual must eat more than slowly growing individuals. Thus, rapid growth rate may increase risk of predation through its association with foraging activity. Individuals that run fast should be capable of capturing prey and evading predators more effectively than individuals that run slowly. Overall, these results emphasize the importance of clutch to variation in phenotypes and survival in hatchling Sceloporus undulatus. / Master of Science