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Bacteria and virus evolution,
a model for the study of natural selection.
This lecture covers the following topics.
Experimental evolution of microbes is a relatively new field in biology,
I'll describe how its foundations trace back to
familiar and pioneering work of 19th century scientists,
especially Gregor Mendel's work on genetics and
Charles Darwin's work on evolution by means of natural selection.
By the mid-20th century,
microbiologists had seized upon these ideas in order to use
bacteria and their viruses to test basic biological principles.
I'll then describe several modern examples of how laboratory experiments with
bacteria can be successfully used to
examine questions relating to parasitism and disease.
First, I will discuss the evolution of antibiotic resistance in bacterial pathogens,
a problem of increasing concern to the medical community,
because bacteria can adapt to
overcome drugs that were previously used in combating disease.
Second, I will discuss the evolution of pathogen virulence,
where empirical studies show that the environment can
select for either increased or decreased virulence
(the harm that a parasite inflicts on its host organism).
Last, I will discuss the evolution of pathogen emergence,
which often involves a parasite mutating to infect a new host and
subsequent selection for the parasite to become
better adapted to exploiting its new host.
I begin with a summary of the many exciting discoveries that
predated modern selection experiments involving bacteria and viruses.