In the era of the Evolutionary Synthesis, genetic recombination or mutation were assumed to create the raw material for evolution by natural selection. More recently, however, the genetic versus environmental basis of new selectable traits, and how genotype × environment interactions affect evolutionary trajectories, has risen to the forefront of evolutionary biology. Phenotypic plasticity [PP] is an individual’s inherent ability to change behaviour, physiology, morphology, or life-history in response to environmental cues. It is new to consider PP as a factor affecting biological invasion success and the process has virtually been ignored in marine environments. I intend to study PP, as the strategy can provide a mechanistic explanation to understand and predict successful invasions. Such knowledge is crucial since global invasions have significant impact on the ecology since invasive species creates genetic pollution and can change ecosystem functions. It has also a huge economic impact since estimated damage and control cost in the U.S. alone reach $138 billion annually. I will utilize common garden experiments as well as a molecular approach with cDNA microarry in order to assess the evolution of PP and study expressed genes, which administrate plasticity genes.