Earth Science: Micro-Organisms
A new fascinating world of microorganisms, invisible to the naked eye, was first made accessible to humans during the 17th century. Antoni van Leeuwenhoek was the first to observe bacteria with a microscope that he built himself.
Bacteria, viruses, as well as single-celled organisms of all kinds are part of life on Earth. They were the first living organisms and even today make up the largest part of living matter. Microorganisms can be found almost everywhere and can exist under extremely harsh environmental conditions such as in hot vents.