Extremophiles 101 | National Geographic

• [Narrator] Intense heat, freezing cold, high acidity, and radioactivity. These harsh environments don't seem hospitable for life, but some organisms not only survive but thrive under such extreme conditions. The name extremophile means extreme lover.

These organisms live in exceptionally harsh environments, such as hot hyperthermal vents or buried in rocks far beneath the Earth's surface. Extremophiles occur in all three domains of life: bacteria, archaea, and eukaryotes. They range from the extreme heat-loving thermophiles, which feed off of inorganic chemicals and have special enzymes to survive high temperatures, to extreme cold-loving psychrophiles, which have evolved antifreeze proteins that help ensure their survival in some of the coldest waters on the planet.

But the most extreme living things on Earth are tardigrades. Also known as water bears, these water-dwelling micro animals are polyextremophiles. This means they are capable of surviving multiple harsh conditions. They are nearly indestructible and have even survived the extreme conditions of outer space.

Tardigrades have a unique adaptation that allows them to curl up into a dry, seemingly lifeless ball and slow down their metabolic rate. In this state, they can survive cold, dry environments like space for decades. Studying the adaptations of extremophiles may hold the key to solving many of Earth's problems.

This includes the development of genetically based medications, producing new types of biofuels, and protecting people against radiation exposure. Extremophiles have opened our minds to the many possibilities of life and the environments that can support it. Understanding the limits of life in these extreme conditions on Earth may provide scientists with clues of how life could possibly exist elsewhere in the universe.