Transcript: The first biological systems capable of independent life on Earth were prokaryotes. Bacteria are familiar example, a single long strand of DNA with several thousand genes. Most prokaryotes are harmless to humans, and in fact they are essential for our form of life and for the survival of more complex organisms. Prokaryotes may have less genetic material than eukaryotes, but they are highly complex chemical factories, many of which are still not understood. In fact, the diversity of chemistry of prokaryotes is still only imperfectly measured because its very hard to culture these in the lab, but in a single teaspoon of seawater there is more genetic material in prokaryotes then in the entire human genome.