The evolution of energy metabolism in ectotherms. Metabolic rate is the rate at which organisms take up, transform, and expend energy and materials. The primary outcome of this initiative is a comprehensive understanding of the effect of climate on the metabolic rate of ectothermic vertebrates, including goannas, fish and toads. Our research will encompass aquatic and terrestrial environments; temperate and tropical habitats; and include both iconic native species and alien invasive ones. We se ....The evolution of energy metabolism in ectotherms. Metabolic rate is the rate at which organisms take up, transform, and expend energy and materials. The primary outcome of this initiative is a comprehensive understanding of the effect of climate on the metabolic rate of ectothermic vertebrates, including goannas, fish and toads. Our research will encompass aquatic and terrestrial environments; temperate and tropical habitats; and include both iconic native species and alien invasive ones. We seek to understand not only how and why species in these environments vary in their metabolic rate, but also the consequences of this variation. Such knowledge will be important in understanding how climate change does and will affect animals and in predicting its consequences.Read moreRead less
Does testosterone produce duds or studs? A performance-based examination of the Immunocompetence Handicap Hypothesis. The evolutionary persistence of testosterone (T) as a vertebrate reproductive hormone is viewed as a double-edged sword. On the one hand T secretion is required for development and expression of appropriate reproductive functions. On the other hand T is known to suppress immune functions and is thus considered a liability to male health. We are examining an alternate hypothesis: ....Does testosterone produce duds or studs? A performance-based examination of the Immunocompetence Handicap Hypothesis. The evolutionary persistence of testosterone (T) as a vertebrate reproductive hormone is viewed as a double-edged sword. On the one hand T secretion is required for development and expression of appropriate reproductive functions. On the other hand T is known to suppress immune functions and is thus considered a liability to male health. We are examining an alternate hypothesis: that T-induced immunosuppression benefits breeding males by protecting their physical performance levels during immune challenge. We will examine this hypothesis by quantifying the interactive effects of T and immune challenge on the aerobic capacity of male birds.Read moreRead less
The evolution of dim light vision in vertebrates. High sensitivity (rod-based) vision has been extremely important for the survival and adaptive radiation of many vertebrates, including humans over evolutionary time. This multidisciplinary project will reveal the evolutionary and physiological constraints on early photoreception and the difficulties in operating over an enormous range of lighting conditions. Not only will the findings be crucial for our understanding of basic mechanisms of dim l ....The evolution of dim light vision in vertebrates. High sensitivity (rod-based) vision has been extremely important for the survival and adaptive radiation of many vertebrates, including humans over evolutionary time. This multidisciplinary project will reveal the evolutionary and physiological constraints on early photoreception and the difficulties in operating over an enormous range of lighting conditions. Not only will the findings be crucial for our understanding of basic mechanisms of dim light vision, but also provide potential insights into the physiological bases of various rod dystrophies affecting humans and the improved design of more sensitive cameras and safe light environments for rearing animals in captivity e.g. for aquaculture.Read moreRead less
Competition between regulatory processes in Amphibians: Testing the effects of physical and physiological factors on thermoregulation and hydroregulation. Regulation of body temperature is important for many animals, and it influences processes such as growth and reproduction. However, it is not clear to what extent wet-skinned animals can control body temperature because of evaporation. Understanding this about frogs is crucial to understanding their habitat requirements and the effects of clim ....Competition between regulatory processes in Amphibians: Testing the effects of physical and physiological factors on thermoregulation and hydroregulation. Regulation of body temperature is important for many animals, and it influences processes such as growth and reproduction. However, it is not clear to what extent wet-skinned animals can control body temperature because of evaporation. Understanding this about frogs is crucial to understanding their habitat requirements and the effects of climate change, habitat modification, and the invasion of cane toads on their populations. Amphibians are in decline worldwide, and research into the basic ways that these animals interact with the physical environment is needed before effective management plans can be produced. The unique physiological characteristics of Australian frogs make this is the best place in the world to do this research.Read moreRead less
Testing the adaptive benefit of physiological acclimation. For over a century, physiologists have observed that organisms can modify their physiological function in response to changes in the environment, a process known as acclimation. However, until recently, the adaptive benefit of these acclimation responses has been assumed rather than tested. In this study, I will utilize the effects of temperature on the ability of male mosquito fish (Gambusia holbrooki) to obtain matings and subsequently ....Testing the adaptive benefit of physiological acclimation. For over a century, physiologists have observed that organisms can modify their physiological function in response to changes in the environment, a process known as acclimation. However, until recently, the adaptive benefit of these acclimation responses has been assumed rather than tested. In this study, I will utilize the effects of temperature on the ability of male mosquito fish (Gambusia holbrooki) to obtain matings and subsequently sire offspring to test the benefit of both thermal acclimation and developmental plasticity. This will allow the most comprehensive test of two important hypotheses in comparative physiology: the Beneficial Acclimation Hypothesis and the Beneficial Developmental Plasticity Hypothesis.Read moreRead less
Evolution of viviparity in reptiles: the fundamental role of junctional complexes. This project utilises unique Australian reptile fauna to understand global questions in fundamental biology. We will discover basic biological information on native species, which will be important in future conservation of Australian ecosystems and animals and ultimately in helping to maintain Australia's biodiversity. The project also provides training opportunities for graduate and undergraduate students in ....Evolution of viviparity in reptiles: the fundamental role of junctional complexes. This project utilises unique Australian reptile fauna to understand global questions in fundamental biology. We will discover basic biological information on native species, which will be important in future conservation of Australian ecosystems and animals and ultimately in helping to maintain Australia's biodiversity. The project also provides training opportunities for graduate and undergraduate students in several different research methods that are widely applicable in the more general Australian workforce. Because the research work is genuinely cross-disciplinary research, its findings are applicable to both biological and medically oriented technologies.Read moreRead less
Uterodomes and the evolution of viviparity. We will test the hypothesis that uterodomes, which are cell structures unique to the early pregnant uterus in mammals, and the cellular changes accompanying their development, are essential to the evolution of viviparity in amniotes. The proposal stems from our recent discovery that uterodomes develop in the uteri of viviparous lizards as well as in mammals, suggesting key commonalities at the cellular level in the evolution of live birth across amnio ....Uterodomes and the evolution of viviparity. We will test the hypothesis that uterodomes, which are cell structures unique to the early pregnant uterus in mammals, and the cellular changes accompanying their development, are essential to the evolution of viviparity in amniotes. The proposal stems from our recent discovery that uterodomes develop in the uteri of viviparous lizards as well as in mammals, suggesting key commonalities at the cellular level in the evolution of live birth across amniote vertebrates. We will take advantage of the unique combination of placental types among Australian lizards, including a species with both oviparous and viviparous populations.Read moreRead less
Environmental control of genetic/phenotypic interactions in lung development: An evolutionary perspective. Vertebrate lungs all contain morphologically and functionally similar lung lining cells. However, the cellular arrangement (i.e. lung morphology) and the function of the surfactant these cells produce, differs dramatically between species. Hence, a subset of highly conserved lung-specific genes coincides with spectacular phenotypic diversity. How has this diversity evolved? Do environmental ....Environmental control of genetic/phenotypic interactions in lung development: An evolutionary perspective. Vertebrate lungs all contain morphologically and functionally similar lung lining cells. However, the cellular arrangement (i.e. lung morphology) and the function of the surfactant these cells produce, differs dramatically between species. Hence, a subset of highly conserved lung-specific genes coincides with spectacular phenotypic diversity. How has this diversity evolved? Do environmental conditions, birth strategy or phylogenetic relationships determine lung phenotype? We will experimentally manipulate developing lungs and cells to demonstrate how environmental conditions (temperature, oxygen, lung-fluid regulation and neuro-hormonal input) promote evolutionary processes by altering gene expression, protein/lipid synthesis, cellular differentiation and hence lung morphology/function in animals with different birth strategies.Read moreRead less
Flexibility in the timing of parturition: the key to viviparity in lizards? Embryos of viviparous lizards usually gain adequate nutrients from yolk. Why then has placentotrophy evolved in some species, and what new opportunities has it opened up? The answer may lie in the advantages gained from flexibility in the timing of birth, made possible by supplementary transfer of storage lipids to embryos during gestation. We argue that this provides a pivotal opportunity for evolutionary divergence: so ....Flexibility in the timing of parturition: the key to viviparity in lizards? Embryos of viviparous lizards usually gain adequate nutrients from yolk. Why then has placentotrophy evolved in some species, and what new opportunities has it opened up? The answer may lie in the advantages gained from flexibility in the timing of birth, made possible by supplementary transfer of storage lipids to embryos during gestation. We argue that this provides a pivotal opportunity for evolutionary divergence: some alpine species exploit flexible parturition; other species replace optional placentotrophy with obligate transfer. Our unique experimental approach, using two well-researched clades of viviparous skinks, will result in new testable hypotheses about the evolution of viviparity.Read moreRead less
Do frogs hydroregulate? Regulation versus tolerance of thermal and hydric states. Amphibians are in decline in Australia and worldwide. Frogs are a middle link in terrestrial and aquatic food chains (as predators and prey) so are important for the sustainability of Australia's biodiversity and as indicators of environmental problems. Basic research about the ways Australian frogs interact with the physical environment to balance body water and temperature is crucial to predicting the effects of ....Do frogs hydroregulate? Regulation versus tolerance of thermal and hydric states. Amphibians are in decline in Australia and worldwide. Frogs are a middle link in terrestrial and aquatic food chains (as predators and prey) so are important for the sustainability of Australia's biodiversity and as indicators of environmental problems. Basic research about the ways Australian frogs interact with the physical environment to balance body water and temperature is crucial to predicting the effects of climate change or habitat modification on frogs. This basic information is needed to produce effective conservation plans for native frogs and management plans for invasive cane toads. We will train students in techniques and concepts in ecology, conservation biology, and animal physiology.Read moreRead less