What Are Microbes? - Definition, Types & Uses

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  • 0:02 What Are Microbes?
  • 0:59 Types of Microbes
  • 2:29 Uses for Microbes in Our World
  • 5:22 Lesson Summary
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Lesson Transcript
Instructor: Wendy McDougal

Wendy has taught high school Biology and has a master's degree in education.

Microbes are the tiny microorganisms that inhabit the world with us, around us, and even in us. Learn more about how these microscopic beings affect our lives.

What Are Microbes?

When a friend informs you that a spider is crawling on your arm, you might react with alarm and try to frantically swat the creature away. Fortunately, this probably doesn't happen often, as we don't normally find things crawling on us. Or do we? That depends on whether or not you are counting the trillions of tiny organisms inhabiting your body on a daily basis.

Welcome to the world of microbes - a massive population of microorganisms too small to see with the naked eye, these creatures are literally everywhere. But before you panic about the fact that they are presently inhabiting your body, it is important to understand that they typically do much more good than harm.

While some examples such as bacteria and viruses are usually to blame when we get sick, the benefits of microbes to our world are vast. In this lesson, learn more about this unseen group of organisms and gain a better understanding of how they fit into our world.

Types of Microbes

As mentioned previously, microbes are found literally everywhere in our world. They live in soil, on plants, and in and on our bodies. They thrive in ponds and streams, and they inhabit our oceans. Microbes are all around us in the air, not to mention on every surface of our home. They have even adapted to living in boiling thermal vents as well as ice-covered lands.

So what exactly are these tiny creatures? There are five main groups of microbes populating our earth. These include bacteria, viruses, fungi, algae and protozoa. You are most likely familiar with some of these organisms. Many of us have a negative association with the thought of bacteria and viruses. When stricken with stomach flu, common cold, infections and other ailments, we start to point fingers at these tiny culprits.

You may know fungi as a group of organisms that include mushrooms and the mold we find lurking in old food. However, one member of this group is a microbe that many of us consume on a daily basis. Yeast, a single-celled microbe, is well known for its ability to ferment sugar in bread dough to make it rise.

In terms of algae, you are probably picturing the green seaweed floating in the lake you swam in last summer. However, some algae species are microscopic, such as marine diatoms. And protozoans are miniscule animal-like creatures that we find in watery environments, such as the blob-like amoeba.

Uses for Microbes in Our World

So, what roles do these microorganisms play in our lives, and what makes them important? Let's start with bacteria.


Although bacteria can cause illness and often get bad press, they also benefit us in many ways. For example, we may panic when we hear of an E. Coli outbreak on the news. However, this is a type of bacteria that lives happily in our intestines, helping us by breaking down our food.

Bacteria are also beneficial in that some are used in antibiotics. There are certain types of bacteria found in soil that actually target and kill other bacteria. And you've no doubt heard of the active cultures in yogurt. Once again, these are healthy bacteria that aid in our digestion. Finally, some bacteria even have the ability to make their own food through photosynthesis. Cyanobacteria is one such microbe, and it contributes oxygen to the atmosphere through this process.

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