Nature Farm

All About Microbes

Bad Guys? Rarely!

150 years ago, it was hard for people to believe that living things too tiny to see—microbes—could cause major human diseases. Today, it might seem equally astonishing to learn that microbes are actually essential to keeping us alive. Of the millions of types of microbes on the planet, disease-causing microbes (pathogens) make up only a very tiny fraction.

 What is a microbe?

The term microbe (which is often used interchangeably with microorganism, bacteria, germ, and even bug) includes bacteria, viruses, some fungi, and other life forms too tiny to see.  Microbes are found in almost every environment on Earth.  

Trillions of Friends...

Humans depend on microbial communities in more ways than you can imagine. For example, microbes: 


  • Make air breathable
  • Keep us healthy
  • Provide sources of new drugs
  • Help us digest food
  • Clean up hazardous chemicals
  • Support and protect crops

Partners for life.

From the moment we were born, microbes began living in and on our bodies.  These early colonizers helped to "educate" our immune systems to differentiate good microbial partners from pathogenic microbes. Amazingly, only about 1 out of 10 cells in the human body is actually a human cell: most of the cells that make up our bodies are microbes!


In fact, humans couldn't have evolved without microbes.  Billions of years ago, microbes converted the Earth's entire atmosphere from nitrogen-based to oxygen-based, making it possible for larger forms of life to evolve. Human evolution has been inextricably linked with the microbes that have surrounded us from the very beginning.

Some of the microbes living in our bodies actually help us fight against pathogens by competing against them for space. This mutually beneficial relationship helps to protect us from getting diseases while giving the microbes a place to live.

Invite a microbe to dinner.  

Many of the foods we eat would be indigestible without the 10-100 trillion microbes living within our guts. Bacteroides the taiotaomicron, for example, helps our bodies process complex sugars. Microbes also play a major role in creating many of the foods we love, such as cheese, yogurt and bread. 

Nature's master chemists.  

news5Hundreds of drugs available today were derived from chemicals first found in microbes. Scientists can use the amazing variety of chemicals microbes naturally produce to create new medicines. 

Livable climate.

Without microbes, we wouldn't have oxygen to breathe. Plants aren't the only things that carry out photosynthesis: photosynthetic microbes are responsible for about half of the photosynthesis on Earth, simultaneously increasing the amount of oxygen and decreasing the amount of carbon dioxide in the air. Through this process, microbes are helping to mitigate some of the greenhouse gasses that cause global warming.  

Healthy farms.  

news7Microbes living in the soil provide plants with natural protection from pests and diseases. They are also essential for converting nitrogen and other nutrients into forms that plants can use to grow.  

 Cleaning up.

Because of their special adaptations, some microbes actually degrade-and thereby render harmless, chemicals that are extremely dangerous to humans. These microbes can help clean up gasoline leaks, oil spills, sewage, nuclear waste, and many other types of pollution. 

Productive ecosystems.


Humans aren't the only ones that depend on microbes for digesting food, fighting disease and maintaining a livable planet. No plants or animals could live without microbes. 

It takes a village.

Most of the things microbes do for our world could never be done by a single type of microbe alone, but require a complex community working together. These communities are like a "bucket brigade"-each individual does just one part to help the whole group function. 

The information on this Web page was derived from the poster Our Microbial Planet and the brochure The Vital Role of Microbes on Earth.