Coevolution

Abstract: Genetic Algorithms is a computational model inspired by Darwin's theory of evolution. It has a broad range of applications from function optimization to solving robotic control problems. Coevolution is an extension of Genetic Algorithms in which more than one population is evolved at the same time. Coevolution can be done in two ways: cooperatively, in which populations jointly try to solve an evolutionary problem, or competitively. Coevolution has been shown to be useful in solving many problems, yet its application in complex domains still needs to be demonstrated.Robotic soccer is a complex domain that has a dynamic and noisy environment. Many Reinforcement Learning techniques have been applied to the robotic soccer domain, since it is a great test bed for many machine learning methods. However, the success of Reinforcement Learning methods has been limited due to the huge state space of the domain. Evolutionary Algorithms have also been used to tackle this domain; nevertheless, their application has been limited to a small subset of the domain, and no attempt has been shown to be successful in acting on solving the whole problem.This thesis will try to answer the question of whether coevolution can be applied successfully to complex domains. Three techniques are introduced to tackle the robotic soccer problem. First, an incremental learning algorithm is used to achieve a desirable performance of some soccer tasks. Second, a hierarchical coevolution paradigm is introduced to allow coevolution to scale up in solving the problem. Third, an orchestration mechanism is utilized to manage the learning processes.

Abstract: The main purpose of this review is to promote discussion on the impact of modern phylogenetic comparative methods has had on several fields of biology. The combining of comparative methods and phyiogenies is used (1) to infer the ancestral States of morphological, ecological and behavioral patterns and to suggest evolutionary patterns of change, (2) to develop hypotheses about the processes of evolutionary change, (3) to test evolutionary association between two or more characters that might suggest coevolutionary processes or evolutionary constraints, and (4) to correct the nonindependence of species data (e.g. statistical problems of interespecific analyses that are not evolutionary in nature). Because of this, the evaluation of adaptation hypotheses has changad dramatically in the last two decades. Now, advances in molecular techniques and phylogenetic reconstruction methods allow researchers to evaluate hypotheses of adaptation using a more robust approach, but Darwinian argumentation or experimental approaches are still used to explain correlation over evolutionary time. My interest here is to ernphasize the use of phyiogenies when testing hypotheses of adaptation and evolution, hypotheses of origin and transition of characters, evolutionary association of two or more characters, coevolution, phylogenetic diversification, and the role that phyiogenies and the comparative methods might play on the idantification and conservation of species at risk. For this reason, I revise eight study cases, including the evolution of (1) dioecy among plants with fleshy fruits dispersed by animais, (2) gregariousness among butterfly larva prometed by aposematic coloration, (3) wing reduction among macrolepidopteran living on stable forests, (4) nectar robbing among bill-serrated hummingbirds, (5) plant chemistry on herbivore host shifts, (6) floral defenses against "aprovechados” that rob nectar, (7) nectarivory among hummingbirds and their adaptive radiation, and (8) host generalization among parasitic cowbirds. The first two systems are used mainly to explain some of the methodological problems and the remaining six conform a conceptual revision of the use of phylogenies for testing hypotheses of adaptation and in biology/evolutionary ecology. Lastiy, I revise how phyiogenies can be used to establish conservation priorities and to identify bilogical processes that might determine different leveis of susceptibility to extinction because of phylogenetic origin