Conditions on Early Earth: Hot and Anoxic

Earth was originally

anoxic

Microorganisms

aka microbes; life forms too small to be seen by the human eye; diverse in form/function; inhabit every environment that supports life; mainly single-celled, some complex structures, some multicellular, live in microbial communities

Types of Microbes

cellular & acellular

Cellular Microbes

prokaryotic & eukaryotic

Prokaryotic microbes

bacteria and archaea

Eukaryotic microbes

protozoa and fungi

Acellular microbes

viruses

Importance of microbes

produce oxygen, serve as food for some aquatic organisms, help digest food, degrade dead plants and organic waste (sewage treatment), convert N₂ into usable forms, make humans healthy, improving food safety & preservation

Commercial Applications of Microbiology

wastewater treatment, fermentation, biotechnology, bioremediation, biofuels

What can microbes produce?

dairy products (cheeses, yogurt, buttermilk) & other food products (sauerkraut, kimchi, pickles, chocolate, coffee, leavened breads, beer)

Microbes as disease agents

has decreased since 1900