This document provides an introduction to microbial diversity. It defines microbes as small living organisms that require a microscope to be seen, including six major groups: bacteria, archaea, algae, protists, fungi, and viruses. The document discusses the morphological, metabolic, ecological, behavioral, and evolutionary diversity of microbes and provides some examples, such as different cell structures, means of obtaining energy like photosynthesis, and habitats like the human gut and acid mine drainage. It notes that microbes play critical roles in biogeochemical cycles, multicellular life, agriculture, and human health.

1. Bacterial Diversity
Dr. Rachel Mackelprang
Biology 418
Spring 2020
Book: Principles of Microbial Diversity by James Brown

2. Introduction to
Microbial Diversity

3. What is a microbe?
Small
Thiomargarita namibiensis Caulerpa taxifola
Loose definition: Requires a microscope to be seen
Some exceptions: Large bacteria and algae
Some small organisms are not microbes

4. What is a microbe?
Small
Thiomargarita namibiensis Caulerpa taxifola
Loose definition: Requires a microscope to be seen
Some exceptions: Large bacteria and algae
Some small organisms are not microbes
Microbes are living creatures: They metabolize food, grow,
reproduce. Except for viruses, which are noncellular.

5. Six major groups of microbes
Prokaryote: organism
lacking nucleus
Bacteria Archaea
Eukaryotes: Organism
whose cells contain a
nucleus
Algae Protists Fungi
Viruses: Noncellular particle
containing genetic material
that takes over cell to
generate more viral particles

6. Microbes are critical:
Just a few examples
Global biogeochemical
cycles
Biology of multicellular
organisms
AgricultureHuman health

7. History of Life on Earth
Earth
and
Mars
Form
Start of
conditions
compatible
with life
First
microorganisms
First
multicellular
organisms
Algae

8. History of Life on Earth
Earth
and
Mars
Form
Start of
conditions
compatible
with life
First
microorganisms
First
multicellular
organisms
Algae
Mars surface
becomes less
habitable

9. What is microbial diversity?
In the macroscopic world, this is an easier question
Ecological MetabolicMorphological
Structural
Behavioral
Book: Ch1 pg 5-10

10. Morphological
Diversity

11. Cell envelope
Endospores
Flagella and pili
Stalks
Structural Diversity

12. CO2 Lithotrophy
Metabolic Diversity
Microbes are MUCH more metabolically diverse than
macroscopic eukaryotes: just a few examples
Photosynthesis
Chemo-
heterotrophy

13. Acid mine
drainage Human gut
Ecological Diversity
We live in a microbial world
Deep sea
vent
Soil

14. Motility
Behavioral Diversity
Sporulating
Streptomyces
coelicolor
Chlorobium symbiotic
consortium
(also see pg 118)

15. Evolutionary
Diversity
Underlies the five
previous aspects
Most phylogenetic types
of organisms are
microbial