Bacteria are believed to have been the first organisms to appear on earth about 4 billion years ago. The oldest known fossils are of bacteria-like life forms. They are microscopic single-cell organisms that are neither plants nor animals, and they exist in their millions. Some bacteria are harmful, yet most are beneficial and essential, as they support many forms of plant and animal life.

Witches Butter (Nostoc commune)
Witches Butter
(Nostoc commune)