Bacteria: A Short (3 Billion Year) History

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When it comes to current events, it’s useful to know the history behind them.  The same can be said of the developments through time that led to the advent of bacteria, and the developments that caused humans to discover and learn about them.

Bacteria have played their part in the evolution of the planet for eons. Fossils of micro-organisms have been discovered in stone dating more than 400 million years old. Some argue that primitive bacteria existed three to four billion years ago, almost as far back as the very beginning of Earth’s history.

(Note: The Altons have written their own book on bacteria, disease, and antibiotics)

Bacteria spent ages as the predominant life form on Earth, going through several mass extinctions and then coming back to occupy the planet again and again. They have left their mark, good and bad, on every species that came after them. Indeed, you have more bacterial cells in your body than human.

The presence of oxygen in the atmosphere and, thus, the possibility of life as we know it, is a consequence of bacteria; specifically, cyanobacteria (sometimes confusingly called, “blue-green algae”). Cyanobacteria were early users of a process called photosynthesis, where water, carbon dioxide, and sunlight combine to produce oxygen. Even today, the part of a plant cell which conducts photosynthesis (called a “chloroplast”) is essentially a cyanobacterium.

good and bad bacteria

Despite this, humans had little idea that bacteria were such a pervasive presence in our world. Indeed, we were completely unaware of their existence, but not the diseases they caused. As new innovations like magnifying glasses in the thirteenth century and simple microscopes in the sixteenth century were developed, we began to learn more about a world previously unknown.

It was not, however, until the invention of a more powerful microscope that bacteria was discovered. In 1676, Dutch “microscopist” Antonie van Leeuwenhoek was the first to publish articles on bacteria and protozoans, which he called “animalcules”, as well as red blood cells and human sperm. Amazingly, his findings were considered mere curiosities, and there were no further reports on bacteria for a hundred years.

Louis Pasteur

By the mid-1800s, however, the connection between bacteria and disease was more fully appreciated as a result of the work of Louis Pasteur. He performed studies to determine why milk and wine go “sour” with time. Pasteur concluded that bacteria were the culprits. He deduced that, if bacteria could make milk or wine “sick”, then why not human beings? This assumption led to the Germ Theory of Disease, which suggested that microbes were the cause of infectious diseases.

Pasteur himself was unable to prove the theory, but a German scientist named Robert Koch performed an experiment that did. He injected mice with bacteria taken from animals that died from anthrax. The injected mice then all developed anthrax in short order.

It took the invention of the light bulb, patented in 1880 by Thomas Edison, for microscope technology to reach its maximum potential. Since then, various new techniques for visualizing microbes have been developed, such as electron microscopy. These greatly improved on the “light” microscope and afforded a more detailed look at bacteria and other micro-organisms.

Those that received the most attention were the ones that caused diseases (also known as pathogens). Many pandemic diseases, like Plague and Cholera, became treatable with the development of antibiotics in early-mid twentieth century. Others, like many viruses, still remain beyond our ability to cure.

Mankind, however, isn’t content to sit on its laurels. Breakthroughs and discoveries occur all the time Here’s an amazing (scary?) one: Scientists led by biologist Craig Venter have managed to create a new bacterium (Mycoplasma laboratorium) in the lab. Yes, the first man-made life-form that can self-replicate. Venter, who’s an acquaintance of SpaceX founder Elon Musk, believes that manufacturing new bacteria may help in terraforming of the surface of Mars.

Back on earth, some Japanese scientists have discovered a species of bacteria that eats the plastic found in disposable water bottles. This might be very helpful in cleaning up the planet, considering that we produce 50 million tons of this stuff every year.

History has not yet completed for either bacteria or mankind. As time progresses, we may still benefit (or suffer) from both Earth’s earliest and latest inhabitants.

Joe Alton MD

Dr. Alton

Hey, looking for medical supplies or a quality medical kit for injuries and illness in good times or bad? Support our mission by checking out Nurse Amy’s entire line at You’ll be glad you did. And learn more about bacterial infections and the antibiotics that eliminate them with a copy of our book “Alton’s Antibiotics and Infectious Diseases: The Layman’s Guide…”

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