Paul Andersen starts with a brief description of the history of life. He then discusses the seven characteristics of life and why viruses are not alive. He then describes the three domains in the current classification system and explains why eukaryotes are more closely related to members of the Archaea domain.

Paul Andersen describes the defining characteristics of the domain Eubacteria. He begins with a quick description of the phylogeny of bacteria and horizontal gene transfer. He then surveys the structures of a bacteria; nucleoid region, capsule, pilli, cell wall with peptidoglycan, flagella. He describes the differing morphologies and metabolism in different bacteria. He describes how bacteria can be Gram positive or Gram negative. He finishes with a brief discussion of quorum sensing.

In this video Paul Andersen describes the defining characteristics of members in the domain archaebacteria. He starts with a brief description of the phylogeny of this group. He then describes the major characteristics on an archaea, such as differences in the phospholipids. He explains how they reproduce through binary fission and finishes with a discussion of archaebacteria diversity.

Paul Andersen discusses the defining characteristics of the members of Domain Eukarya. He starts with a brief description of the phylogeny of life on earth. He then discusses the major characteristics of eukaryotic cells. He explains how eukaryotic cells evolved from prokaryotic cells using endosymbiosis and infolding. He finally discusses the metabolism and reproduction found in eukaryotes.

Crash Course Biology #35 - Hank veers away from human anatomy to teach us about the (mostly) single-celled organisms that make up two of the three taxonomic domains of life, and one of the four kingdoms: Archaea, Bacteria, and Protists. They are by far the most abundant organisms on Earth, and are our oldest, oddest relatives.