The History of Microbiology

Chapter 1-2 Lecture

First Microorganisms on Earth

• Fossils of primitive microbes found in ancient rock formations date back to 3.5 billion years ago; animals and humans appeared about 900 million years ago.

• The first microbes on Earth are archaea and cyanobacteria. Stromatolites; fossils left

behind by ancient microbes.

Earliest Known Infectious Diseases

• Infectious diseases have been around for a very long time, probably as long as humans and animals have existed.

• Evidence of bacterial diseases such as tuberculosis and syphilis, is observed in the bones and organs of mummies.

Early Microbiology

Significant events in the early history of microbiology include the development of: • Microscopes• Bacterial staining procedures• Techniques that enabled microorganisms to be cultured

(grown) in the lab• Steps to prove that specific microbes were responsible for

causing specific diseases.

New truths become evident when new tools become available

Pioneers in the Science of Microbiology

• Anton van Leeuwenhoek (1632-1723)• “Father of Microbiology”• Made many simple single-lens microscopes that would

magnify an object 200 to 300 times its size.• Used his microscopes to examine almost anything;

scrapings from his teeth, water from ponds, blood, and sperm.

• First to observe the existence of tiny microscopic creatures and called them ”animalcules”.

One of Leeuwenhoek’s letters convincing scientists of the existence of microbes

• “Tho my teeth are kept usually very clean, nevertheless when I view them in a Magnifying Glass, I find growing between them a little white matter…then to my great surprise that [matter] contained very many small living Animals…The number of these Animals in the scurf of a mans Teeth, are so many that I believe they exceed the number of Men in a kingdom.”

- Engelkirk, p. 7

• Louis Pasteur (1822-1895)

• Disproved the theory of spontaneous generation.

• Developed pasteurization, a process used to kill pathogens in a liquid using heat.

• Discovered life forms that could exist without oxygen (anaerobes).

• Developed a vaccine to prevent rabies in dogs and successfully used the vaccine to treat human rabies.

Pioneers in the Science of Microbiology

Koch’s Postulates

Pioneers in the Science of Microbiology

• Robert Koch (1843-1910)• Established a procedure, called

Koch’s Postulates, to prove that a specific microbe is the cause of a specific infectious disease. For example, M. tuberculosis causes tuberculosis.

• Discovered that some microbes produce spores capable of protecting the microbe.

• Developed methods to grow bacteria using a petri dish.

The History of Microbiology

Main Ideas• Create 3 main

idea questions about the details to the right of your notes.

Summary• Write 2-3

sentences summarizing the topics in your notes.

• USE YOUR OWN WORDS!

Vocabulary• Highlight

important vocabulary words in your notes.