Microorganisms are small. The microbial world is extremely diverse.
 

What groups make up the microbal world?
 

What is the major differenc between viruses and other microbes?
 

The microbial world of little animicules was first described in the 17^th century by Antonie von Leeuwoenhoek.

Modern microbiology began in the mid 19^th century. Its disciplinary roots are in agriculture, chemistry, and medicine.

French chemist, Louis Pasteur, first recognized fermentation as a microbial process. His attempts to cure "wine diseases" led to the germ theory of disease.

 
Who developed the protocol that helped determine microbial etiology?
 

Dutch professor, Martinus Beijerinck, realized that microbes were responsible for maintaining soil fertility and stressed the underlying biochemical unity of life.

Microorgansisms are everywhere; the environment selects. One half of the earth's biomass consists of microorganisms. Plants=35%, Animals=15%.

Microbial habitats: soil: rhizosphere, 1 mile down; water: fresh, brackish, marine, hypersaline; in and on plants and animals, other microorganisms.

The human body contains about 10¹³ human cells. There are 10¹⁴ bacterial cells in or on the human body. These are normal flora, not pathogens. Very few microorganisms are pathogens.
 

What are symbiotic relationships?
 

Without microorganisms, all other organisms would die. The most important role of microbes is as biogeochemical agents, particularly the breakdown of organic molecules and the interconversion of inorganic ones. Microbes make sewage disposal plants possible.

Microorganisms are important in food production. Fermented foods. Single cell protein.

 
What is the most abundant organic material on earth?
 

Applied microbiology: bioremediation, industrial processes, genetic engineering.

Microorganisms occupy all three domains (superkingdoms) into which living organisms are now classified. See text Figure 10.2.

Eukaryotic microorganisms are classified into kingdoms of the Domain Eucarya. The green algae are members of the Plant Kingdom. The yellow algae, brown algae, dinoflagellates, diatoms, protozoa, and slime molds are found in the Kingdom Protista, while the fungi have a kingdom of their own.

There are two domains for the prokaryotic microorganisms. The Domain Eubacteria includes of the cyanobacteria, the green and purple photosynthetic bacteria, the mycoplasmas, and the Gram positive and Gram negative bacteria. The Domain Archaea includes the methanogens, extreme halophiles, and extreme thermoacidophiles.

Viruses, being acellular parasites of cells, are not classified into any domain or kingdom.the cellular organisms.

Of all the groups of microorganisms, the eubacteria are the best understood. Eubacteria are commonly referred to, simply, as bacteria. Among the eubacteria the Gram positive and Gram negatives have been most studied. These bacteria are identified by their reaction to the Gram Stain and cell wall structure.
 

What are the distinguishing characteristics of most G - bacteria? and G + bacteria?
 

Important Gram Postivie Bacteria:
 

ENTERICS

PSEUDOMONADS 

GREEN SULFUR, PURPLE SULFUR PHOTOSYNTHETIC BACTERIA
 

Important Gram Negative Bacteria:

LACTIC ACID BACTERIA
 
SPORE-FORMERS
 
MICROCOCCI