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Extreme Life 

Types of Extremophiles

We study life in its extreme on Earth in hopes of understanding how it might exist on other planets where conditions aren't as hospitable to life.

What is an extremophile? Well it's not a snowboarder that loves to take 40 foot cliff drops or water ski barefoot at 90 miles per hour. Extremophiles are life forms that thrive outside the ranges life is commonly found in.

Microbes hold almost all records for survivability in these hostile environments. They also excel at exploiting different sources of energy. For these reasons, and others, many people believe that the sort of life most likely to be encountered on other worlds will be microbial.

According to Wikipedia there are many types of extremophiles including:

  • Acidophile: An organism with an optimum pH level at or below pH 3.
  • Alkaliphile: An organism with optimal growth at pH levels of 9 or above.
  • Endolith: An organism that lives inside rocks.
  • Halophile: An organism requiring at least 2M of NaCl for growth.
  • Hyperthermophile: An organism that can thrive at temperatures between 80-110 °C.
  • Hypolith: An organism that lives inside rocks in cold deserts.
  • Metalotolerant: capable of tolerating high levels of heavy metals, such as copper, cadmium, arsenic, and zinc.
  • Oligotroph: An organism capable of growth in nutritionally limited environments.
  • Piezophile: An organism that lives optimally at high hydrostatic pressure.
  • Polyextremophile: An organism that can survive different extreme conditions.
  • Psychrophile: An organism that can thrive at temperatures of 15 °C or lower.
  • Radioresistant: resistant to high levels of ionizing radiation.
  • Thermophile: An organism that can thrive at temperatures between 60-80 °C.
  • Xerophile: An organism that can grow in environments with a low water activity.

It's All Greek to Me


By understanding the origins of scientific words, we can understand what complex names mean, or even make up our own.

  • Halo - salt
  • Lith - rock
  • Cryo - cold
  • Endo - "inside"
  • Exo - "outside"
  • Hyper - "extreme"
  • Oligo - "few, little"
  • Piezo - "pressure"
  • Phile - from greek "philos" meaning "love of". A halophile would be a bacteria that loves living in salty environments.
  • Photo - "light"
  • Poly - "many"
  • Psychro - "cold"
  • Thermo - heat
  • Troph - "nourish" Chemotrophs receive nourishment from chemicals. Phototrophs receive it from light.
  • Xero - "dry"