13  •  Evolution and Diversity Among the Microbes 533

Bacteria, archaea, protists, and viruses: the unseen world

There are microbes in all three domains. 534

13.1

Not all microbes are closely related evolutionarily. 534

13.2

Microbes are the simplest but most successful organisms on earth. 535

Bacteria may be the most diverse of all organisms. 538

13.3

What are bacteria? 538

13.4

Bacterial growth and reproduction is fast and efficient. 539

13.5

Metabolic diversity among the bacteria is extreme. 541

In humans, bacteria can have harmful or beneficial health effects. 543

13.6

Many bacteria are beneficial to humans. 543

13.7

This is how we do it: Are bacteria thriving in our offices, on our desks? 544

13.8

Bacteria cause many human diseases. 545

13.9

Sexually transmitted diseases reveal battles between microbes and humans. 546

13.10

Bacteria’s resistance to drugs can evolve quickly. 548

Archaea exploit some of the most extreme habitats. 550

13.11

Archaea are profoundly different from bacteria. 550

13.12

Archaea thrive in habitats too extreme for most other organisms. 551

Most protists are single-celled eukaryotes. 553

13.13

The first eukaryotes were protists. 553

13.14

There are animal-like protists, fungus-like protists, and plant-like protists. 554

13.15

Some protists can make you very sick. 556

Viruses are at the border between living and non-living. 557

13.16

Viruses are not exactly living organisms. 557

13.17

Viruses are responsible for many health problems. 559

13.18

Viruses infect a wide range of organisms. 560

13.19

HIV illustrates the difficulty of controlling infectious viruses. 561

StreetBIO: KNOWLEDGE YOU CAN USE

The five-second rule: how clean is that food you just dropped? 564