For information on a specific unit, click on the first letter of its name: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z. Answers to the three most frequently asked questions:
Microorganisms were the first living creatures on earth. It is estimated there are a total of 5 nonillion microorganisms on earth (5x1020). You will find nearly 10 million a millilitre of ocean water and 40 million in a gram of soil. They are also ubiquitous on the human body.
A: While not every microorganism is dangerous, some microorganisms can cause disease and infections in humans and other living things. Microorganisms, also called microbes, also contribute to decomposition and spoilage of food, and they can leave toxic waste products behind even if they are eradicated from the contaminated material.