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Evolution has traditionally been a historical and descriptive science, and predicting future evolutionary processes has long been considered impossible. However, evolutionary predictions are increasingly being developed and used in medicine, agriculture, biotechnology and conservation biology. Evolutionary predictions may be used for different purposes, such as to prepare for the future, to try and change the course of evolution or to determine how well we understand evolutionary processes. Similarly, the exact aspect of the evolved population that we want to predict may also differ. For example, we could try to predict which genotype will dominate, the fitness of the population or the extinction probability of a population. In addition, there are many uses of evolutionary predictions that may not always be recognized as such. The main goal of this review is to increase awareness of methods and data in different research fields by showing the breadth of situations in which evolutionary predictions are made. We describe how diverse evolutionary predictions share a common structure described by the predictive scope, time scale and precision. Then, by using examples ranging from SARS-CoV2 and influenza to CRISPR-based gene drives and sustainable product formation in biotechnology, we discuss the methods for predicting evolution, the factors that affect predictability and how predictions can be used to prevent evolution in undesirable directions or to promote beneficial evolution (i.e. evolutionary control). We hope that this review will stimulate collaboration between fields by establishing a common language for evolutionary predictions.

Ecological processes have the potential to influence evolution through their effects on selection. This thesis explores the effects of two ecological factors - competition and ecological opportunity. Intraspecific (within-species) competition is often expected to drive adaptation and diversification by increasing selection for the use of novel resources, thereby alleviating the detrimental effects of competition. However, this is not always the expected outcome; theory suggests that intraspecific competition can also drive convergent evolution. On the other hand, interspecific (between-species) competition is usually expected to impede adaptation and diversification because competitor species occupy potential available niches, preventing the focal species from diversifying to do so. In this thesis, I review previous experimental studies exploring the effects of competition on adaptive diversification, and then directly test these effects using experimental evolution of the bacterium Pseudomonas fluorescens. I confirm that intraspecific competition drives adaptive diversification, while the effects of interspecific competition are varied. Strong interspecific competition impedes adaptation and diversification, while the presence of weak, non-diversifying interspecific competitors drives diversification through increased resource competition. The presence of ecological opportunity is essential for adaptation and diversification, and so variation in attributes of those opportunities is expected to have important effects on the dynamics of adaptive evolution. In another evolution experiment with P. fluorescens, I tested the effects of variation in ecological opportunity on adaptive evolution and found that the type and arrangement of ecological opportunities drives adaptation but, in this system, not diversification. I also show that ecological opportunity drives differences in the degree of parallel evolution at the phenotypic and genotypic level. Finally, I explore some unexpected genetic changes identified in one of these evolved populations - two synonymous mutations that conferred fitness benefits, and show that the observed fitness improvements are the result of increased gene expression. I have shown that ecological processes can play an important role in shaping the evolutionary trajectories taken by populations. Understanding the interactions between ecological and evolutionary processes is vital for our understanding of evolutionary dynamics as a whole, and the studies laid out in this thesis represent valuable contributions to this field of study.