Guess how many Guess how many bacteria are in a single bacteria are in a single handful of soil? handful of soil?

A single A single gramgram of soil (the of soil (the size of a pencil eraser) size of a pencil eraser) has 2.5 billion bacteria, has 2.5 billion bacteria, so a handful would so a handful would contain contain trillionstrillions!!

There are more types of There are more types of bacteria on Earth than all bacteria on Earth than all other living things other living things combinedcombined

Most bacteria are too Most bacteria are too small to see without a small to see without a microscopemicroscope

The largest known The largest known bacteria are 1,000 bacteria are 1,000 times larger than the times larger than the average bacteriumaverage bacterium

One of these giant One of these giant bacteria lives inside a bacteria lives inside a surgeonfish—it is 0.6 surgeonfish—it is 0.6 mm long and can be mm long and can be seen with the naked seen with the naked eyeeye

Characteristics of Characteristics of BacteriaBacteria

Bacteria make up the Bacteria make up the kingdomskingdoms Eubacteria and Eubacteria and ArchaebacteriaArchaebacteriaThese two kingdoms contain These two kingdoms contain the oldest forms of life on the oldest forms of life on EarthEarthAll bacteria are All bacteria are singlesingle-celled -celled organismsorganismsBacteria are usually one of Bacteria are usually one of threethree main shapes: bacilli, main shapes: bacilli, cocci, or spirillacocci, or spirilla

The Shape of BacteriaThe Shape of Bacteria

Most bacteria have a rigid Most bacteria have a rigid cell wallcell wall that gives them their that gives them their shapeshape

Each Each shapeshape of bacteria of bacteria helps it in a different wayhelps it in a different way

Some bacteria have Some bacteria have hairlikehairlike parts, called flagella, which parts, called flagella, which spin and help push a spin and help push a bacterium through water or bacterium through water or other liquidsother liquids

Bacilli (rod shaped)

Cocci (spherical)

Spirilla (long and spiral shaped)

BacilliBacilli

– Rod shapedRod shaped

– Large surface area (take in nutrients Large surface area (take in nutrients quickly, but dry out easilyquickly, but dry out easily

CocciCocci

– SphericalSpherical

– Do not Do not dry outdry out as quickly as bacilli as quickly as bacilli

SpirillaSpirilla

– Use flagella at both ends to move like a Use flagella at both ends to move like a corkscrewcorkscrew

No Nucleus!No Nucleus!

All bacteria are single-All bacteria are single-celled and do not have celled and do not have a a nucleusnucleus

This makes bacteria a This makes bacteria a prokaryoteprokaryote

Prokaryotes function as Prokaryotes function as independentindependent organismsorganisms

Prokaryotes reproduce Prokaryotes reproduce differently than differently than eukaryotes doeukaryotes do

Bacterial ReproductionBacterial Reproduction

Bacteria reproduce by process Bacteria reproduce by process of of binary fissionbinary fission

Binary fission: a form of Binary fission: a form of asexualasexual reproduction in a single-celled reproduction in a single-celled organism by which one cell organism by which one cell divides into two cells of the divides into two cells of the same sizesame size

No nucleus, so DNA is just a No nucleus, so DNA is just a circular circular looploop with no membrane with no membrane

DNA is copied, loops separate

New cell wall forms and cells separate

EndosporesEndospores

Most species of bacteria do well in Most species of bacteria do well in warmwarm, , moist placesmoist places

In cold or dry surroundings, the bacteria In cold or dry surroundings, the bacteria will either will either diedie or become inactive and form or become inactive and form endosporesendospores

EndosporesEndospores: contains : contains geneticgenetic material and material and proteins and is covered by a thick, proteins and is covered by a thick, protective protective coatcoat

Many endospores Many endospores survive in cold, hot, survive in cold, hot, and very dry and very dry placesplaces

When conditions When conditions improve, the improve, the endospores endospores break break openopen, and the , and the bacteria become bacteria become activeactive again again

Scientists found Scientists found endospores inside an endospores inside an insect that was insect that was preserved in preserved in amberamber for 30 million yearsfor 30 million years

When the endospores When the endospores were moistened in a were moistened in a lab, bacteria began to lab, bacteria began to grow!grow!

Kingdom EubacteriaKingdom Eubacteria

Eubacteria are classified by the way they Eubacteria are classified by the way they get their get their foodfoodMost are Most are consumersconsumers, which get food by , which get food by eating other eating other organismsorganismsMany bacteria are Many bacteria are decomposersdecomposers, which , which feed on feed on deaddead organisms organismsEubacteria that make their food are Eubacteria that make their food are producers producers (use energy from sunlight to (use energy from sunlight to make own food, often make own food, often greengreen))

CyanobacteriaCyanobacteria– Are producersAre producers– Usually live in Usually live in

waterwater– Contain green Contain green

pigment pigment chlorophyllchlorophyll

– Some have a Some have a blue tint that blue tint that helps in helps in photosynthesisphotosynthesis

Other Other cyanobacteria cyanobacteria have a red have a red pigmentpigment

Flamingos get Flamingos get their their pinkpink color color from eating red from eating red cyanobacteriacyanobacteria

Kingdom ArchaebacteriaKingdom ArchaebacteriaThree main types of Archaebacteria: heat Three main types of Archaebacteria: heat lovers, lovers, saltsalt lovers, and lovers, and methanemethane makers makers

Heat loversHeat lovers– Live in ocean Live in ocean ventsvents and hot springs and hot springs– Live in very hot water, can survive temps of more Live in very hot water, can survive temps of more

than 250 degrees Celsiusthan 250 degrees Celsius

Salt loversSalt lovers– Live in environments of high salt, like the Dead Sea Live in environments of high salt, like the Dead Sea

and Great Salt Lakeand Great Salt Lake

Methane makersMethane makers– Give off methane Give off methane gasgas and live in and live in swampsswamps and animal and animal

intestinesintestines

Heat lovers in ocean vent

Methane makers in swamp

Salt lovers in Dead Sea

Harsh environmentsHarsh environments– Archaebacteria often Archaebacteria often

live where nothing else live where nothing else cancan

– Most prefer Most prefer environment with little environment with little to no to no oxygenoxygen

– Very different from Very different from eubacteriaeubacteria

– Not all archaebacteria Not all archaebacteria have have cell wallscell walls

– When they do, the cell When they do, the cell walls are chemically walls are chemically different from different from eubacteriaeubacteria