08/21/25
Microbes are ubiquitous
● They are everywhere
A small subset of microbes cause diseases
● Humans
● Animals
● Plants
Critical roles in environment
● Food chains
● Perform nutrient cycling (N,C,P,S)
● Photosynthesis
● agriculture
Ectremophiles
Microbes that live in extreme environments
● Hyperthermophile:
○ hot temps
● Psychrophiles:
○ cold temps
● Barophiles:
○ pressure
● Halophiles:
○ Salt
● Acidophile:
○ Highly acidic; low pH
● Alkaliphile:
○ Highly Basic; high pH
● Xerophile:
○ Low water
Microbiology:
● The study of microscopic organisms:
○ Bacteria
, ○ Viruses
○ Arcahea
○ Fungi
○ Parasites
Microbes and Humans
Microbes cover your:
● Skin
● Mouth GI tract
● Respiratory tract
● Urogenital tract
… you have more microbial cells than human cells!
… most of these organisms are commensals or mutualists (discourage pathogens, contribute to
your health)
Chikungunya Virus:
● Zoonotic disease
○ Transmitted via mosquitoes
● Symptoms:
○ Fever, joint pain, etc.
Horsehair Worm (Nematophora)
● Eukaryotic parasites of arthropods (larvae)
● Infection impacts insect host
What does microbiology encompass?:
● Microbial ecology
● Pathogenesis
● Immunology
● biotechnology/biodremediation
● Food microbiology
● Public health and epidemiology
Cyanobacteria:
● Ancient (3bil years ago)
● Globally important (lake eerie big green blob)
Freshwater blooms:
● Toxic
● All continents except antarctica
Lake Erie cyanoHABs:
, ● Worst in history
*Half of all the breaths you take are from algae in the ocean*
Microcystis spp.:
● Widely distributed HAB organism
● Potential to produce toxic microcystin
08/26/25
What is an extremophile?
● An organism that requires an extreme environment
MATCH EXTREMOPHILE TO DEFINITION FOR EXAM!!!!!!!!!!!!!!!!!!!!!!
Name a type of microbe that is NOT bacteria or virus:
● Fungi
● Archae
● parasites
Founding Microbiologists:
● First microscopic observations
○ Robert Hooke (fungi & molds)
○ Antoni Van Leeuwenhoek (pioneer of microscopy)
Spontaneous Generation:
● Decay of organic matter generates microbes
○ Abiogenesis vs. Biogenesis
○ Louis Pasteur
Abiogenesis:
● Life can originate from non-living material
Biogenesis:
● Living things only arise from living things
Louis Pasteur:
● Disproved spontaneous generation
● Experiments resulted in pasteurization
Inductive Reasoning:
● Make observations and develop an explanation (or hypothesis)
Deductive Reasoning:
, ● Take an explanation for a phenomenon (hypothesis) and make observations to
determine whether that explanation is supported
Hypothesis:
● An explanation of some phenomenon that acts as a starting point for investigation
Theory:
● A collection of statements and concepts (largely agreed upon) that explains some
natural event
Vaccination:
● Smallpox
○ Severe symptoms: fever, malaise, rash, toxemia, shock
● Edward Jenner!!!!!
○ An English physician
○ Observed that “dairymaids” would contract cowpox, have mild symptoms, and
appeared immune to smallpox
○ Hypothesis: cowpox is closely related to smallpox
○ Experiment: Inoculate James Phipps
Germ theory:
● microorganisms are the causative agent of disease
● Dr. Oliver Wendell Holmes
○ Women who gave birth in hospitals developed fewer infections
● Dr. Ignaz Semmelweis
○ Women in maternity wards are more likely to develop infection if treated by
physicians who had just performed autopsies.
● Joseph Lister
○ Disinfect hands prior to surgery
● Robert Koch and his postulates (KOCH’S POSTULATES (4 rules (mouse example)))
○ Koch’s Postulates are used to ID causative agents of microbial diseases: Bacillus
anthracis
■ 1. Suspected pathogen present in all disease animals and absent from
healthy animals
■ 2. Suspected pathogen must be isolated in pure culture
■ 3. The pure culture should be able to be used to infect and cause disease
in a healthy host
■ 4. The suspected pathogen must be re-isolated from the new host
Microbes are ubiquitous
● They are everywhere
A small subset of microbes cause diseases
● Humans
● Animals
● Plants
Critical roles in environment
● Food chains
● Perform nutrient cycling (N,C,P,S)
● Photosynthesis
● agriculture
Ectremophiles
Microbes that live in extreme environments
● Hyperthermophile:
○ hot temps
● Psychrophiles:
○ cold temps
● Barophiles:
○ pressure
● Halophiles:
○ Salt
● Acidophile:
○ Highly acidic; low pH
● Alkaliphile:
○ Highly Basic; high pH
● Xerophile:
○ Low water
Microbiology:
● The study of microscopic organisms:
○ Bacteria
, ○ Viruses
○ Arcahea
○ Fungi
○ Parasites
Microbes and Humans
Microbes cover your:
● Skin
● Mouth GI tract
● Respiratory tract
● Urogenital tract
… you have more microbial cells than human cells!
… most of these organisms are commensals or mutualists (discourage pathogens, contribute to
your health)
Chikungunya Virus:
● Zoonotic disease
○ Transmitted via mosquitoes
● Symptoms:
○ Fever, joint pain, etc.
Horsehair Worm (Nematophora)
● Eukaryotic parasites of arthropods (larvae)
● Infection impacts insect host
What does microbiology encompass?:
● Microbial ecology
● Pathogenesis
● Immunology
● biotechnology/biodremediation
● Food microbiology
● Public health and epidemiology
Cyanobacteria:
● Ancient (3bil years ago)
● Globally important (lake eerie big green blob)
Freshwater blooms:
● Toxic
● All continents except antarctica
Lake Erie cyanoHABs:
, ● Worst in history
*Half of all the breaths you take are from algae in the ocean*
Microcystis spp.:
● Widely distributed HAB organism
● Potential to produce toxic microcystin
08/26/25
What is an extremophile?
● An organism that requires an extreme environment
MATCH EXTREMOPHILE TO DEFINITION FOR EXAM!!!!!!!!!!!!!!!!!!!!!!
Name a type of microbe that is NOT bacteria or virus:
● Fungi
● Archae
● parasites
Founding Microbiologists:
● First microscopic observations
○ Robert Hooke (fungi & molds)
○ Antoni Van Leeuwenhoek (pioneer of microscopy)
Spontaneous Generation:
● Decay of organic matter generates microbes
○ Abiogenesis vs. Biogenesis
○ Louis Pasteur
Abiogenesis:
● Life can originate from non-living material
Biogenesis:
● Living things only arise from living things
Louis Pasteur:
● Disproved spontaneous generation
● Experiments resulted in pasteurization
Inductive Reasoning:
● Make observations and develop an explanation (or hypothesis)
Deductive Reasoning:
, ● Take an explanation for a phenomenon (hypothesis) and make observations to
determine whether that explanation is supported
Hypothesis:
● An explanation of some phenomenon that acts as a starting point for investigation
Theory:
● A collection of statements and concepts (largely agreed upon) that explains some
natural event
Vaccination:
● Smallpox
○ Severe symptoms: fever, malaise, rash, toxemia, shock
● Edward Jenner!!!!!
○ An English physician
○ Observed that “dairymaids” would contract cowpox, have mild symptoms, and
appeared immune to smallpox
○ Hypothesis: cowpox is closely related to smallpox
○ Experiment: Inoculate James Phipps
Germ theory:
● microorganisms are the causative agent of disease
● Dr. Oliver Wendell Holmes
○ Women who gave birth in hospitals developed fewer infections
● Dr. Ignaz Semmelweis
○ Women in maternity wards are more likely to develop infection if treated by
physicians who had just performed autopsies.
● Joseph Lister
○ Disinfect hands prior to surgery
● Robert Koch and his postulates (KOCH’S POSTULATES (4 rules (mouse example)))
○ Koch’s Postulates are used to ID causative agents of microbial diseases: Bacillus
anthracis
■ 1. Suspected pathogen present in all disease animals and absent from
healthy animals
■ 2. Suspected pathogen must be isolated in pure culture
■ 3. The pure culture should be able to be used to infect and cause disease
in a healthy host
■ 4. The suspected pathogen must be re-isolated from the new host
