An organism that can live in extreme environments is called an extremophile. These organisms have adapted to conditions that are often inhospitable to most life forms, such as high temperatures, extreme salinity, or pH levels. Examples include thermophiles, which thrive in hot springs, and halophiles, which flourish in salty lakes. Extremophiles provide insights into the limits of life on Earth and help scientists speculate about the possibility of life in similar extreme conditions elsewhere in the universe.