41:32
Humans and bacteria
This program presents the human body as a complex ecosystem of bacteria, then examines each portion of the body, which bacteria live there, and why. The three major bacterial groups - sphere-shaped cocci, rods, and helical spirochetes and spirilla -...
36:32
Viruses
Viruses are the simplest forms of life - so primitive in biological terms that for some years the scientific community debated whether they should even be regarded as living organisms. This program examines how viruses, though incapable of reproduci...