Microbes were the first forms of life on Earth and they can be found virtually everywhere. Bacteria, viruses, fungi, and parasites are able to evolve quickly to adapt and survive in a variety of habitats. They’re in the air we breathe, the water we drink, the dirt we stand on, and on everything we touch. A single teaspoon of soil can contain up to one billion bacteria cells, over 100,000 fungal cells, and thousands of protozoans. Ever wonder what causes morning breath? P. gingivalis is one of 500 bacterial species that occupy the human mouth!

Most microbes, like Paramecia, are ideal citizens of the Earth, living freely in the environment and not harming others. Many are probiotic, meaning they’re beneficial to humans. Lactobacillus bulgaricus and L. acidophilus are used to turn milk into yogurt! Some microbes, however, cause diseases that have devastated human life like Black Death, which has caused several deadly pandemics throughout history.

Although many can cause disease to humans, microorganisms are crucial to the environment and natural life cycle of all living organisms. They’re here to stay!