key concept the current tree of life has three domains

KEY CONCEPT The current tree of life has three domains.

Classification is always a work in progress.

• The tree of life shows our most current understanding. • New discoveries can lead to changes in classification.

– Until 1866: only two kingdoms,Animalia and Plantae

Animalia

Plantae

Classification is always a work in progress.

• The tree of life shows our most current understanding. • New discoveries can lead to changes in classification.

– Until 1866: only two kingdoms,Animalia and Plantae

– 1866: all single-celled organisms moved to kingdom Protista

Animalia

Protista

Plantae

Classification is always a work in progress.

• The tree of life shows our most current understanding. • New discoveries can lead to changes in classification.

– Until 1866: only two kingdoms,Animalia and Plantae

– 1938: prokaryotes moved to kingdom Monera

– 1866: all single-celled organisms moved to kingdom Protista

Animalia

Protista

Plantae

Monera

• The tree of life shows our most current understanding. • New discoveries can lead to changes in classification.

– Until 1866: only two kingdoms,Animalia and Plantae

Classification is always a work in progress.

– 1938: prokaryotes moved to kingdom Monera

– 1866: all single-celled organisms moved to kingdom Protista

Monera

– 1959: fungi moved to own kingdom

Fungi

Protista

Plantae

Animalia

• The tree of life shows our most current understanding.

• New discoveries can lead to changes in classification.– Until 1866: only two kingdoms,

Animalia and Plantae

Classification is always a work in progress.

– 1938: prokaryotes moved to kingdom Monera

– 1866: all single-celled organisms moved to kingdom Protista

– 1959: fungi moved to own kingdom

– 1977: kingdom Monerasplit into kingdoms Bacteria and Archaea

Animalia

Protista

Fungi

Plantae

Archea

Bacteria

The three domains in the tree of life are Bacteria, Archaea, and Eukarya.

• Domains are above the kingdom level. – proposed by Carl Woese based on rRNA studies of

prokaryotes– domain model more clearly shows prokaryotic diversity

• Domain Bacteria includes prokaryotes in the kingdom Bacteria.

– one of largest groups on Earth– classified by shape, need for

oxygen, and diseases caused

– known for living in extreme environments

• Domain Archaea includes prokaryotes in the kingdom Archaea.

– cell walls chemically different from bacteria

– differences discovered by studying RNA

• Domain Eukarya includes all eukaryotes.

– kingdom Protista

• Domain Eukarya includes all eukaryotes.

– kingdom Protista

– kingdom Plantae

• Domain Eukarya includes all eukaryotes.

– kingdom Protista

– kingdom Plantae

– kingdom Fungi

• Domain Eukarya includes all eukaryotes.

– kingdom Protista

– kingdom Plantae

– kingdom Fungi

– kingdom Animalia

• Bacteria and archaea can be difficult to classify.

– transfer genes among themselves outside of reproduction– blurs the line

between “species” – more research

needed tounderstand prokaryotes

bridge to transfer DNA

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THE FIVE KINGDOM

S

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BACTERIA

Bacteria - small one celled monerans

Bacteria like a warm, dark, and moist environment

They are found almost everywhere:

-water -air

-soil -food

-skin -inside the body

-on most objects

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Spiral:spirilla

rod-shaped: bacilli, bacillus

Round:cocci

3 Shapes of Bacteria

Bacteria are classified by shape into 3 groups:

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3 Shapes of Bacteria

Bacillus anthracis – (bacillus)

Neisseria meningitidis (coccus)

Leptospira interrogans – (spirilla)

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7 Major Structures of a Bacteria Cell

•Capsule

•Cell wall

•Ribosomes

•Nucleoid

•Flagella

•Pilli

•Cytoplasm

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Capsule

7 Major Structures of a Bacteria Cell

keeps the cell from drying out and helps it stick to food or other cells

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Cell wall

7 Major Structures of a Bacteria Cell

Thick outer covering that maintains the overall shape of the bacterial cell

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Ribosomes

7 Major Structures of a Bacteria Cell

cell part where proteins are made

Ribosomes give the cytoplasm of bacteria a granular appearance in electron micrographs

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Nucleoid

7 Major Structures of a Bacteria Cell

a ring made up of DNA

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Flagella

7 Major Structures of a Bacteria Cell

a whip-like tail that some bacteria have for locomotion

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Pilli

7 Major Structures of a Bacteria Cell

hollow hair-like structures made of protein

allows bacteria to attach to other cells.

Pilli-singular Pillus-plural

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Cytoplasm

7 Major Structures of a Bacteria Cell

clear jelly-like material that makes up most of the cell

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•Binary Fission- the process of one organism dividing into two organisms

•Fission is a type of asexual reproduction

Reproduction of Bacteria

How?...The one main (circular) chromosome makes a copy of itselfThen it divides into two

•Asexual reproduction- reproduction of a living thing from only one parent

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BINARY FISSION

Bacteria dividing Completed

Reproduction of Bacteria

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•The time of reproduction depends on how desirable the conditions are

•Bacteria can rapidly reproduce themselves in warm, dark, and moist conditions

•Some can reproduce every 20 minutes

(one bacteria could be an ancestor to one million bacteria in six hours)

Reproduction of Bacteria

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Bacterial Cell & Nucleiod DNA Ring

DNA replication

Cell wall synthesis

Cell separation

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Bacteria Survival

Endospore- •a thick celled structure that forms inside the cell

•they are the major cause of food poisoning

•they can withstand boiling, freezing, and extremely dry conditions

•it encloses all the nuclear materials and some cytoplasm

•allows the bacteria to survive for many years

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Bacillus subtilisEndospore-the black section in the middle

highly resistant structures

can withstand radiation, UV light, and boiling at 120oC for 15 minutes.

Bacteria Survival

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Bacteria Survival – Food sources

parasites – bacteria that feed on living things

saprophytes – use dead materials for food (exclusively)

decomposers – get food from breaking down dead matter into simple chemicals

important- because they send minerals and other materials back into the soil so other organisms can use them

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Harmful Bacteria

• some bacteria cause diseases

•Animals can pass diseases to humans

Communicable Disease – Disease passed from one organism to another

This can happen in several ways:•Air•Touching clothing, food, silverware, or toothbrush•Drinking water that contains bacteria

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Human tooth with accumulation of bacterial plaque (smooth areas) and calcified tartar (rough areas)

Harmful Bacteria

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Helpful Bacteria

•Decomposers help recycle nutrients into the soil for other organisms to grow

•Bacteria grow in the stomach of a cow to break down grass and hay

•Most are used to make antibiotics

•Some bacteria help make insulin

•Used to make industrial chemicals

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E.coli on small intestines

Helpful Bacteria

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•Used to treat sewage          

Organic waste is consumed by the bacteria, used as nutrients by the bacteria, and is no longer present to produce odors, sludge, pollution, or unsightly mess.

•foods like yogurt, cottage & Swiss cheese, sour cream, buttermilk are made from bacteria that grows in milk

Helpful Bacteria

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Controlling Bacteria

3 ways to control bacteria:

1) Canning- the process of sealing food in airtight cans or jars after killing bacteria

•endospores are killed during this process

2) Pasteurization- process of heating milk to kill harmful bacteria

3) Dehydration- removing water from food

•Bacteria can’t grow when H2O is removed

•example: uncooked noodles & cold cereal

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Controlling BacteriaAntiseptic vs. Disinfectants

Antiseptic- chemicals that kill bacteria on living things

•means – “against infection”

Examples: iodine, hydrogen peroxide, alcohol, soap, mouthwash

Disinfectants- stronger chemicals that destroy bacteria on objects or nonliving things

Archaebacteria and Eubacteria

• Bacteria are of immense importance because of their rapid growth, reproduction, and mutation rates, as well as, their ability to exist under adverse conditions.

• The oldest fossils known, nearly 3.5 billion years old, are fossils of bacteria-like organisms.

• Bacteria can be autotrophs or hetertrophs.

• Those that are classified as autotrophs are either photosynthetic, obtaining energy from sunlight or chemosynthetic, breaking down inorganic substances for energy .

• Bacteria classified as heterotrophs derive energy from breaking down complex organic compounds in the environment. This includes saprobes, bacteria that feed on decaying material and organic wastes, as well as those that live as parasites, absorbing nutrients from living organisms.

• Depending on the species, bacteria can be aerobic which means they require oxygen to live

or

• anaerobic which means oxygen is deadly to them.

Green patches are green sulfur bacteria. The rust patches are colonies of purple non sulfur bacteria. The red patches are purple sulfur bacteria.

Archaebacteria

Methanogens These Archebacteria are anaerobes. They make methane (natural gas) as a waste product. They are found in swamp sediments, sewage, and in buried landfills. In the future, they could be used to produce methane as a byproduct of sewage treatment or landfill operation.

HalophilesThese are salt-loving Archaebacteria that grow in places like the Great Salt Lake of Utah or salt ponds on the edge of San Francisco Bay. Large numbers of certain halophiles can turn these waters a dark pink. Pink halophiles contain a pigment very similar to the rhodopsin in the human retina. They use this visual pigment for a type of photosynthesis that does not produce oxygen. Halophiles are aerobes, however, and perform aerobic respiration.

Extreme halophiles can live in extremely salty environments. Most are photosynthetic autotrophs. The photosynthesizers in this category are purple because instead of using chlorophyll to photosynthesize, they use a similar pigment called bacteriorhodopsin that uses all light except for purple light, making the cells appear purple.

ThermophilesThese are Archaebacteria from hot springs and other high temperature environments. Some can grow above the boiling temperature of water. They are anaerobes, performing anaerobic respiration.

Thermophiles are interesting because they contain genes for heat-stable enzymes that may be of great value in industry and medicine. An example is taq polymerase, the gene for which was isolated from a collection of Thermus aquaticus in a Yellowstone Park hot spring. Taq polymerase is used to make large numbers of copies of DNA sequences in a DNA sample. It is invaluable to medicine, biotechnology, and biological research. Annual sales of taq polymerase are roughly half a billion dollars.

Eubacteria

CyanobacteriaThis is a group of bacteria that includes some that are single cells and some that are chains of cells. You may have seen them as "green slime" in your aquarium or in a pond.

Cyanobacteria can do "modern photosynthesis", which is the kind that makes oxygen from water. All plants do this kind of photosynthesis and inherited the ability from the cyanobacteria.

Cyanobacteria were the first organisms on Earth to do modern photosynthesis and they made the first oxygen in the Earth's atmosphere.

• Bacteria are often maligned as the causes of human and animal disease. However, certain bacteria, the actinomycetes, produce antibiotics such as streptomycin and nocardicin.

• Other Bacteria live symbiotically in the guts of animals or elsewhere in their bodies.

• For example, bacteria in your gut produce vitamin K which is essential to blood clot formation.

• Still other Bacteria live on the roots of certain plants, converting nitrogen into a usable form.

• Bacteria put the tang in yogurt and the sour in sourdough bread.

• Saprobes help to break down dead organic matter.

• Bacteria make up the base of the food web in many environments.

Streptococcus thermophilus in yogurt

• Bacteria are prokaryotic and unicellular.

• Bacteria have cell walls.

• Bacteria have circular DNA called plasmids

• Bacteria can be anaerobes or aerobes.

• Bacteria are heterotrophs or autotrophs.

• Bacteria are awesome!

• Bacteria can reproduce sexually by conjugation or asexually by binary fission.

Endospore

• Bacteria can survive unfavorable conditions by producing an endospore.

Shapes of Bacteria