Microbiology - reading notes week one

Members of the microbial world 

• Microorganisms are defined as those organisms too samall to be seen clearly by the unaided eye 
• Some microbes such as bread molds and filamentous photosynthetic microbes are visible without microscope. 
• Maceoscopic microbes oftern consist of small aggregation of cells. 
• Macroscopic microorgnaims are multicecellular. 
• Cellular microbes are usually smaller than 1 millimeter in diameter, oftern unicellular and if multicellular lack differentiated tissues. 
• Microorganisms, microbiologists study a variety of acellular biological entities. 
• These include virueses and subvial agents. 
• Microorganisms and microbe are sometimes applied to these acellular agents as well. 
• Members of domain Bacteria are usually single-celled organisms.
• Bacteria contan the molecule peptidoglycan. 
• More microbial cells are found in and on the human body than there are human cells. 

Microbes have envolved and diversified for billions of years

• A review reminds us that in terms of the number of taxa, microbes are dominant organism on Earth. 
• Study of microbial evolution is based on the scentific method. 

Theories of the origin of life depend primarily on indirect evidence 

Dating meterorites through the use of radioisotopes places our planet at an estimates 4.5 to 4.6 billion years old.

Theories of the origin of life depend primarily on indirect evidence 

• Dating meteorities through the use of radiostopes places our planet at an estimate 4.5…