The term for a natural selection mechanism based on mating preferences is sexual selection. This process occurs when individuals with certain traits are more attractive to potential mates, increasing their chances of reproduction. Such traits can include physical characteristics, behaviors, or displays that signal fitness or genetic quality. Sexual selection can lead to marked differences between sexes, or sexual dimorphism, and is a significant force shaping evolutionary processes. It contributes to the diversity of species and can influence population dynamics and adaptations.