Lecture 1
? 1.1 Microbiology
? 1.2 Microorganisms as Cells
? 1.3 Microorganism and Their Natural
Environments
? 1.4 The Impact of Microorganisms on
Humans
What is Microbiology?
? The science of microorganisms (very small,
unicellular organisms)
? The discipline is just over a century old
? Has given rise to molecular biology and
biotechnology
What are Microbes?
Figure 1.2a Bacterial cells viewed with light microscope
Figure 1.2b Bacterial cell viewed with electron microscope
Root Nodule
Bacteroids within Root Nodule
Why study Microbiology?
? Microorganisms were the first life on earth
? Microorganisms created the biosphere that allowed
multicellular organisms to evolve
? Multicellular organisms evolved from
microorganisms
? >50% of the biomass on earth is comprised of
microorganisms
? Microorganisms will be on earth forever
4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0
BYA
Formation of
O2 atmosphereCyanobacterial microfossils(oxygenic photosynthesis)
Earth formed
First microorganisms?
algae,
marine invertebrates insects
mammals
No free O2
Reducing environment
Why study Microbiology?
? Our understanding of life has arisen largely
from studies of microorganisms
(biochemistry and genetics)
? Studies of microorganisms continue to
contribute to fundamental knowledge of life
processes
? We still know very little about the
microorganisms that are present on Earth
Figure 1.4
Why study Microbiology?
? Health
? Agriculture
? Food
? Environment
Infectious diseases are no longer the leading cause of death in North America,due to the
development and use of antimicrobial agents,and improved sanitary practices