Selection pressure refers to the environmental factors that influence which individuals within a population are more likely to survive and reproduce. These factors can include predators, competition for resources, climate change, and other challenges that organisms must adapt to in order to successfully reproduce. Selection pressure plays a key role in driving evolution and shaping the genetic diversity of a population over time. By favoring certain traits or characteristics, selection pressure can lead to the emergence of new species or the extinction of others. Researchers study selection pressure to better understand how organisms adapt to their environments and evolve over time.