Living to the Extreme: Organisms that Survive in the Harshest Environments

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Planet Earth is home to a variety of species, but some interesting specimens take existence and survival to extreme levels. It doesn’t matter whether it’s searing temperatures, frosty environments, or even outer space; these organisms shrug it all off.

What is their secret to survival, and how can the best minds in science learn from them?

Thermophiles and hyperthermophiles

These are two groups of microbes that prefer living in either hot or scorching places. The Thermus Aquaticus is an example of a thermophile, while the Pyrococcus Furiosus is one example of a hyperthermophile.

In 1969, a team of researchers from Indiana University first discovered T. Aquaticus in the hot springs of Yellowstone National Park in the US. Their findings revealed that the microbe has a heat-tolerant DNA-polymerising enzyme, which allows it to thrive in searing temperatures.

The discovery of DNA polymerase paved the way for the development of polymerase chain reaction  (PCR) analysis. PCR tests are widely used in crime scene forensics and genome analysis today.

  1. Furiosus, on the other hand, prefers water temperatures that reach up to 1000° Celsius. It was first found in Italy’s Vulcano Islands when scientist Karl Stetter visited in 1980. There are reports of scientists at the University of Georgia altering the microbe’s DNA to enable it to transform carbon dioxide into fuel.
  2. Radiation defying bacteria

Then some microbes can withstand tremendous amounts of radiation. One example is Deinococcus radiodurans or Conan the Bacterium, as scientists and science geeks alike prefer to call it.

It was discovered in the 1950s when scientists were testing the radiation resistance of several bacteria. Conan the Bacterium emerged triumphantly and stood above the rest.

lab technician checking something in the microscope

Researchers found that it could survive radiation 3,000 times more deadly than the exposure level that would typically kill humans. Key to its toughness is a unique set of antioxidants that protect and rapidly repair its essential proteins.

Today, the scientific community is looking into practical ways to extract these antioxidants and apply them to radiation treatment and recovery.

Cold-resistant life forms

The cold never bothered them anyway. Glacial ice worms and wood frogs thrive in freezing environments.

The normal-looking glacial ice worm is a few centimeters long and thrives in temperatures that reach the freezing mark. They feed on algae and other types of smaller worms. Once the temperature rises to about 4° Celsius, they start dying off. Ice worms are found only in the coldest regions of some countries like Tibet and Alaska.

Wood frogs also roam the North American landscape, and during the winters, they completely freeze. However, the wood frog’s biochemical composition prevents ice crystals from forming and keeps its vital organs intact.

Some researchers are studying the wood frog’s unique internal chemicals to improve human organ storage during transplant procedures. Organs can only be stored for a few hours in ultra-low temperature laboratory freezers and refrigerators.


It’s safe to say these organisms are the overachievers of the bunch. The best example is the microscopic tardigrade. It can survive in all kinds of extreme environments, whether high or low temperatures, excessive radiation, or lack of oxygen.

Tardigrades enter a state of suspended animation called cryptobiosis, which temporarily shuts off normal body functions. They are capable of staying in this state for extended periods (some observations found tardigrades doing this for decades).

They can also survive conditions in outer space. This has prompted scientists to study these organisms further to find out how humans can survive life outside of Earth.

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