Seven Wonders of the Microbe World

The good, the bad and the ugly sides of germs.

Since their first appearance 3.5 billion years ago, microbes have been responsible for some of the most devastating cases of disease and death across the globe. From the Black Death to food poisoning, human contact with these tiny organisms can have dire consequences.

But there is an upside to bacteria. Constituting 90% of the cells in our bodies – mostly in our gut and on our skin – they are essential for sustaining human life on Earth.

This video from the Open University reveals why germs aren't all bad. From their involvement in the history of beer-making to their place in the nitrogen cycle, we discover the ways bacteria are proving themselves useful.

Today, scientists are using microbes to create alternatives to fossil fuels, and to cure disease. It's hoped they could also provide clues as to whether there is life beyond our planet. Since many bacteria survive in extreme and inhospitable environments on Earth, it could mean microbial life exists in similarly hostile conditions, like the freezing permafrost on Mars.