ARCHAEBACTERIA
EUBACTERIA
ARCHAEBACTERIA

Major Characteristics
Generally only live in very harsh environments, such
as those w/o O2—also known as extremophiles
because they can survive pressures over 200 atm
 Microscopic: diameters between 0.0002-0.0004
inches

Cell Type: prokaryotes (DNA not enclosed in nuclei)
 Cell Structure: similar to bacteria but different
chemical composition in cell wall & cell
membrane, few internal organelles
 Body Plan: unicellular

ARCHAEBACTERIA
Metabolism: autotroph or heterotroph
 Reproduction: asexual (binary fission)
 4 major Phyla:

Crenarchaeotes: live in hottest, most acidic
environments
 Kararchaeotes: newly discovered in Yellowstone,
may be least-evolved lineages of modern life
 Nanoarchaeotes: one species exists, relatively
unknown, smallest genome of any organism
 Euryarchaeotes: very diverse group

ARCHAEBACTERIA
Some live in environments
that are so harsh
pressures reach 1 ton/cm2
EUBACTERIA

Major Characteristics
Differ from archaebacteria by chemical composition
 Are vital in recycling nutrients
 Grow in all environments, from guts of animals to
soil and radioactive waste

Cell Type: prokaryotes
 Cell Structure: variety of cell shapes: sperical,
rodlike, spiral; few if any internal organelles,
some have external flagella
 Body Plan: unicellular

EUBACTERIA



Metabolism: autotroph or heterotroph
Reproduction: asexual (binary fission)
4 major Phyla:
Proteobacteria: includes E. coli and nitrogen-fixing
bacteria in soil
 Spirochaetes: distinctive spiral shape; some cause syphilis
and Lyme disease
 Actinobacteria: many soil bacteria belong here; some
produce antiobiotics (streptomycin), some produce harmful
illnesses: anthrax, tetanus, botulism; one produces a
powerful insecticide used for genetic engineering in plants
 Cyanobacteria: photosynthetic; among oldest organisms on
Earth; are key sources of C and N in the environment
