Key Biological Issues in Ecology: I. Physiological How is physiology coupled to environment and genetics? What are the genetic constraints on physiology, anatomy and morphology, and how have these evolved? How does an organism function as a unified whole? How do physiological and behavioral mechanisms act to affect survival and reproduction at the population level? What traits cause certain groups to be very dominant on the planet? How important is variability (in environment, genetics, habitats) in maintaining populations? How do we deal with environment-genotype interactions? II. Population What factors regulate populations? What are the consequences of population structure (size, age, spatial, social) on maintaining populations? How might we best couple theory and experiments, given the difficulty and expense of field experiments? How does plasticity of responses to environment affect the structure and evolution of populations? What is the role of dispersal versus vegetative growth and reproduction in maintaining populations? How important are competitive interactions? What is the role of disease and host/parasite interactions in controlling populations and the effect on their evolution? III. Communities What determines community diversity and stability? How does trophic structure evolve? What are the roles of disturbance and environmental variability in maintaining communities? Are there general food web patterns which exist across the planet? What is the role of competition in determining community patterns? How does resource partitioning occur? How do we couple movement and transport of energy and materials between communities? IV. Ecosystems How do nutrients and energy move through a systems? How does succession operate, i.e. what are the dynamics of nutrient and energy flows through a system? How do we couple very different communities across a landscape? How do we ascertain ecosystem productivity? What controls the biogeochemistry of a system? How does an ecosystem respond to stresses? How do we couple processes acting on vastly different temporal and spatial scales to address real world problems of environmental management? How do we couple knowledge of flows within ecosystems to build knowledge of global-scale processes? When Can an Ecologist Ignore Physiology? Physiology (morass of within-organism characteristics which specify how an individuals life processes respond to environment) seems to skip levels in ecology - very much ignores at population/community level, but important in ecosystems approaches. Why? Focus on nutrient and energy flows leads to reductionist focus on processes. How does physiology enter into other hierarchical levels: (a) Defines a structuring of populations based upon physiological characteristics - VARIATION (b) Provides a means to couple organisms responses to environment - PROCESS So if focus avoided differences between individuals and was not dependent upon environmental conditions, can ignore physiology - which is exactly case in classical population biology models. If focus is on how individual variability affects population and community dynamics, can still ignore physiology by making assumptions about nature of variability between individuals - partial differential equations and stochastic differential equations approach I claim that to consider effects of environmental factors requires either a phenomenological approach (based upon observed responses of physiology), or mechanistic approach (process models which track a "standard individual" or individual-based approaches.