Extremophiles: Definition & Examples

Extremophiles: Definition & Examples
Coming up next: Disease Control & Prevention

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:03 What Are Extremophiles?
  • 1:07 Types of Extremophiles
  • 2:34 Living in Acid
  • 3:07 Living in Antarctic Waters
  • 3:47 Living in Heat
  • 4:21 Lesson Summary
Add to Add to Add to

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up


Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Giulietta Spudich

Giulietta has taught college students, graduate students and researchers in scientific topics from genomics to biochemistry. She has a PhD in Molecular and Cell Biology.

Extremophiles live in conditions outside the moderate environments that most life requires. From high-temperature, deep sea vents to freezing, polar oceans, we'll explore life in some of the most extreme environments on Earth.

What Are Extremophiles?

From tiny, single-celled organisms to complex creatures such as ourselves, most of the wondrous life on Earth thrives in moderate conditions. These are environments where it is 'not too hot, not too cold, but just right,' to take a line from the fairytale Goldilocks. Moderate conditions can also refer to salt content, or pH (a measure of how acidic or how basic an environment is). Most organisms require an environment that has a more neutral pH: 'not too acidic, not too basic, but just right.'

However, a whole class of organisms not only survives in extreme conditions, they thrive! Extremophiles (which loosely translates to 'lovers of extremes') are adapted to what is considered on Earth to be an extreme environment. From Antarctic ice to hydrothermal vents, extremophiles can be adapted to live in extreme cold, intense heat, harsh acidity, high saltiness, and a host of other conditions in which we humans have been surprised to detect life at all.

Types of Extremophiles

Extremophiles are adapted to their particular extreme environment; it's not just that they can live there. To thrive, extremophiles must live in their special environment. For example, if a human put on a thick parka and spent some time in Antarctica, it wouldn't make a human an extremophile. An extremophile is genetically adapted to its extreme environment. That means it's unlikely to survive in moderate conditions.

Let's look at some of the classifications of extremophiles. The key to the classification is in the name, which refers to the environment they are adapted to. Most extremophiles are microorganisms, but a few more complex extremophiles exist.

Thermophiles are heat-loving and are found in environments like deep sea vents, volcanic soil, and around geysers.

Psychrophiles, also known as cryophiles, are just the opposite. These organisms are adapted to cold and live in places like polar seas.

Halophiles thrive in high salt conditions. They live in brine and may be found in salt flats or lakes.

Acidophiles are adapted to extremely acidic conditions, such as volcanic landscapes.

If an organism is adapted to multiple extreme conditions, it's labeled a polyextremophile. For example, a thermoacidophile is adapted to hot (or thermo) and acidic (or acido) conditions.

Now let's meet some of these 'extreme' organisms!

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create An Account