1. The evolutionary tree of life can be documented with evidence.
Bacteria
Archae-
bacteria
Animalia
Fungi
Protista
Plantae
4500
4000
3500
3000
2500
2000
500
1500
1000
Formation of earth
Molten-hot surface of
earth becomes cooler
Oldest definite fossils
of prokaryotes
Appearance of oxygen
in atmosphere
of eukaryotes
First multicellular
organisms
Appearance of animals
and land plants
Colonization of land
by animals
Paleozoic
Mesozoic
Cenozoic
Millions of years ago
ARCHEAN
PRECAMBRIAN
PROTEROZOIC
The evolutionary tree of life can be documented with evidence.
Fossils
Genetics
Physiology

2. Archaebacteria & Bacteria
Eukaryote
Prokaryote
Classification
Old 5 Kingdom system
Monera
Protists
Plants
Fungi
Animals
Archaebacteria & Bacteria

3. Classifying Life Molecular data challenges 5 Kingdoms
Monera was too diverse
2 distinct lineages of prokaryotes
Protists are still too diverse
not yet sorted out

4. 3 Domain system Domains = “Super” Kingdoms Bacteria Archaea Eukarya
extremophiles = live in extreme environments
methanogens
halogens
thermophiles
Eukarya
eukaryotes
protists
fungi
plants
animals

5. Kingdom Archaebacteria
Kingdom Protista
Kingdom Fungi
Kingdom Plantae
Kingdom Animalia
Kingdom Archaebacteria
Kingdom Bacteria

6. Domain Bacteria Domain Archaebacteria
Prokaryotes
Domain Bacteria
Domain Archaebacteria
Domain
Bacteria
Archaea
Eukarya
Common ancestor

7. Bacteria live EVERYWHERE!
Bacteria live in all ecosystems
on plants & animals
in plants & animals
in the soil
in depths of the oceans
in extreme cold
in extreme hot
in extreme salt
on the living
on the dead

8. Bacterial diversity rods and spheres and spirals… Oh My! Rods Spheres

9. Prokaryote Structure Unicellular Size Internal structure
eukaryote cell
Prokaryote Structure
prokaryote cell
Unicellular
bacilli, cocci, spirilli
Size
1/10 size of eukaryote cell
1 micron (1um)
Internal structure
no internal compartments
no membrane-bound organelles
only ribosomes
circular, naked DNA
not wrapped around proteins

10. Variations in Cell Interior
cyanobacterium (photosythetic) bacterium
aerobic bacterium
internal membranes for photosynthesis like a chloroplast (thylakoids)
internal membranes for respiration like a mitochondrion (cristae)

11. Prokaryote Cell Wall Structure
peptide side
chains
cell wall
peptidoglycan
plasma membrane
protein
Gram-positive bacteria
peptidoglycan = polysaccharides + amino acid chains
lipopolysaccharides = lipids + polysaccharides
Gram-negative bacteria
peptidoglycan
plasma
membrane
outer
outer membrane of lipopolysaccharides
cell wall

12. Prokaryotic metabolism
How do bacteria acquire their energy & nutrients?
photoautotrophs
photosynthetic bacteria
chemoautotrophs
oxidize inorganic compounds
nitrogen, sulfur, hydrogen…
heterotrophs
live on plant & animal matter
decomposers & pathogens

13. Genetic variation in bacteria
Mutations
bacteria can reproduce every 20 minutes
binary fission
error rate in copying DNA
1 in every 200 bacteria has a mutation
Genetic recombination
bacteria swap genes
plasmids
small supplemental circles of DNA

14. Genetic variation in bacteria
Transformation
Taking in DNA from the environment
Cell surface receptors recognize closely related DNA and take it in!
Griffith experiment, showing genetic material could be transferred

15. Genetic variation in bacteria
Transduction
Bacteriophages
Specialized viruses that infect bacteria only
Take DNA from one bacteria to another
Like a mosquito carrying a parasite

16. Genetic variation in bacteria
Conjugation
Two bacteria are temporarily joined by a pilus
One way only

17. Bacteria as pathogens Disease-causing microbes plant diseases
wilts, fruit rot, blights
animal diseases
tooth decay, ulcers
anthrax, botulism
plague, leprosy, “flesh-eating” disease
STDs: gonorrhea, chlamydia
typhoid, cholera
TB, pneumonia
lyme disease

18. Bacteria as beneficial (& necessary)
Life on Earth is dependent on bacteria
decomposers
recycling of nutrients from dead to living
nitrogen fixation
only organisms that can fix N from atmosphere
needed for synthesis of proteins & nucleic acids
plant root nodules
help in digestion (E. coli)
digest cellulose for herbivores
cellulase enzyme
produce vitamins K & B12 for humans
produce foods & medicines
from yogurt to insulin

19. Any Questions??