9217293 Padilla Some organisms are able to respond to changing environments during their lifetime, while others are not; their morphology, physiology, or behavior may be fixed, not allowing quick responses to their environmental changes. The objectives of the proposed research are to understand the conditions favoring the ability of an organism to change the way it is built (its morphology) during its lifetime as opposed to having a fixed morphology. This will be accomplished by direct experimentation and observation as well as the use of mathematical and computer models. The PI will use the feeding structures of the marine snail, Lacuna, as a model system for this study. The animal is abundant, easy to breed and use for laboratory and field experiments, and is known to have a feeding morphology that can change when these snails move to different environments and eat different foods. The environmental cues that are used by these snails to induce new feeding structures and measure the consequences of these changes for an animal's feeding rate, growth rate, and lifetime reproduction will be determined.. With the use of mathematical and computer models the PI can make predictions about conditions that would favor individuals that can change their morphology as opposed to having a fixed morphology. These would include how often the environment changes (or individuals move from one environment to another), how long it takes for a new feeding structure to form, and what the cost (for example in reduced feeding rate) of having a feeding structure mismatched to the environment. These predictions will be directly tested on th ese marine snails. The PI will also determine if there is a genetic basis for differences in these features among snails, and examine closely related species to determine the evolutionary patterns associated with being able to change morphology with changing environments. *** ~ ! ! ! F 4 CG Times Symbol & Arial Tms Rmn " Helv 8 8 h / Rochelle D Ray Rochelle D Ray
