Prokaryotes include two domains with enormous diversity

23

How many phyla in the domain bacteria?

phylum Proteobacteria

group of gram-negative bacteria that exemplify the overall diversity within their domain

1. ex. purple sulfur bacteria carry out photosynthesis

phylum Cyanobacteria

first to produce O2

1. ex. photosynthetic plankton form symbiotic relationships with fungi

phylum Spirochaetes

includes some medically important bacteria

1. ex. Borelia burgdorferi —> causes lyme disease

   Treponema Pallidum —> causes syphillis

phylum Firmicates

contains gram-positive bacteria

1. low proportion of guanine and cytosine (G and C)

2. ex. Bacillus anthracis — anthrax

   Clostridium tetani — tetanus

phylum Actinobacteria

another phylum of gram-positive bacteria

1. source of infection-fighting antibiotics

phylum Chlamydiae

Cannot generate ATP of their own

1. obligate parasites

2. Chlamydia —> cell walls lack peptidoglycan

   1. so penicillin cannot kill it

   2. different antibiotics used

obligate parasite

must live in a host cell

extremophiles

Many archaea are considered

4

How many superphyla of archaea are there?

Euryarchaeta

is a superphyla of archaea

1. contains methanogens

2. also includes halophilic archaea that use light energy to produce ATP in very salty habitats

methanogens

live in stagnant waters and in the anaerobic intestines of many animals

1. release large quantities of methane gas

TACK

a superphylum of archaea

1. includes species that thrive in acidic hot springs or at hydrothermal vents on the ocean floor

1. also called Thermoproteota

DPANN

a superphylum of archaea

1. some symbionts

2. live on cell surfaces of other microbes

Asgard

A superphylum of archaea

1. contains archaea most related to the eukaryotic branch of life’s family tree

bacteria and archaea

What two are essential to all life?