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Bacteria Archae-bacteria

AnimaliaFungiProtista Plantae

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Formation of earth

Molten-hot surface ofearth becomes cooler

Oldest definite fossilsof prokaryotes

Appearance of oxygenin atmosphere

Oldest definite fossilsof eukaryotes

First multicellularorganisms

Appearance of animalsand land plants

Colonization of landby animalsPaleozoic

Mesozoic

Cenozoic

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The evolutionary tree of life can be documented with evidence.1. Fossils2. Genetics3. Physiology

The evolutionary tree of life can be documented with evidence.1. Fossils2. Genetics3. Physiology

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Archaebacteria&

Bacteria

Classification Old 5 Kingdom system

Monera Protists Plants Fungi Animals

Prokaryote

Eukaryote

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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

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3 Domain system Domains = “Super” Kingdoms

Bacteria Archaea

extremophiles = live in extreme environments methanogens halogens thermophiles

Eukarya eukaryotes

protists fungi plants animals

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KingdomProtista

KingdomFungi

KingdomPlantae

KingdomAnimalia

KingdomArchaebacteria

KingdomBacteria

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Prokaryotes

Domain Bacteria

Domain Archaebacteria

DomainBacteria

DomainArchaea

DomainEukarya

Common ancestor

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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

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Bacterial diversityrods and spheres and spirals… Oh My!

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Prokaryote Structure 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

prokaryotecell

eukaryote cell

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Variations in Cell Interior

aerobic bacteriumcyanobacterium

(photosythetic) bacterium

internal membranesfor photosynthesislike a chloroplast(thylakoids)

internal membranesfor photosynthesislike a chloroplast(thylakoids)

internal membranes

for respiration

like a mitochondrion

(cristae)

internal membranes

for respiration

like a mitochondrion

(cristae)

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Prokaryote Cell Wall Structure

peptide sidechains

cell wallpeptidoglycan

plasma membrane

protein

Gram-positive bacteria

Gram-negative bacteria

peptidoglycan

plasmamembrane

outermembrane

outer membrane of lipopolysaccharides

cell wall

peptidoglycan = polysaccharides + amino acid chainslipopolysaccharides = lipids + polysaccharides

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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

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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

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Genetic variation in bacteriaTransformation 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

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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

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Genetic variation in bacteriaConjugation Two bacteria are temporarily

joined by a pilus One way only

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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

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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

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Any Questions??