Classification – Chapter 18

Early Systems of Classification

• Taxonomy – naming and grouping organisms according to their characteristics and evolutionary history.

• Aristotle first classified organisms 2,000 years ago. “Classify This”

• He classified living things as either plants or animals.

• Grouped animals into: land dwellers, water dwellers, air dweller.

Early systems of Classification cont…

• Grouped plants by: differences in their stems.• Biologists realized that Aristotle’s categories were

not adequate.• They found that using common names for

organisms caused a problem because they were named differently from place to place. Ex. Robin, called something different elsewhere

• Common names may not describe species accurately. Ex. Jellyfish; it isn’t a fish at all, starfish, koala bear

Linnaeus’s System

• Carolus Linnaeus (1707-1778)

• Came up with a system of grouping organisms.

• He used the organism’s morphology (form and structure) to categorize it.

Levels of Classification

• Made up a hierarchy of seven different levels of organization to classify organisms.

Keep KingdomPlates PhylumClean ClassOr OrderFamily FamilyGets GenusSick Species

Kingdoms

• Linneus seperated organisms into two kingdoms: plant and animal.

• Phylum – subset in the animal kingdom.• Division – subset in the plant kingdom.• Within a phylum or division there are subsets

called classes.• Subset within a class is an order.• Then family then genus and lastly species.

Examples:

BobcatKingdom AnimaliaPhylum/division ChordataClass MammaliaOrder CarnivoraFamily FelidaeGenus LynxSpecies Lynx rufus

Scientific Name

Genus name + species name

Binomial Nomenclature

• Bi-two• Two naming systemGenus + species identifierHumans are known by our genus, homo and

species name, sapiens meaning “wise”-scientific name is underlined or in italics.Linnaeus’s system is still used today.

• Sometimes Botanists split species into subsets known as varieties.

• Peaches and nectarines are fruits of two slightly different varieties of the peach tree, Prunus persica.

• Zoologists refer to variations of a species that occur in different geographic areas as subspecies.

• Subspecies name follows the species identifier.• Ex. Terrapene carolina triungui subspecies of

the common eastern box turtle. Gets its name by having three, rather than four toes on its hind feet.

Phylogeny

• Evolutionary history of organism.• Scientists consider the organism’s phylogeny

when classifying it.• Linnaeus focused on features that are largely

influenced by genes that are clues to common ancestry.

• Review Game

• Building a Cladogram

Homework

• Pg. 339• Questions: 1-6

• Wiki-space go to Chapter 18 page.

• Imperium ("Empire") - the phenomenal world • Regnum ("Kingdom") - the three great divisions of

nature at the time - animal, vegetable, and mineral • Classis ("Class") - subdivisions of the above, in the

animal kingdom six were recognized (mammals, birds, amphibians, fish, insects, and worms)

• Ordo ("Order") - further subdivision of the above - the class Mammalia has eight

• Genus - further subdivisions of the order - in the mammalian order Primates there are four. e.g. Homo

• Species - subdivisions of genus, e.g. Homo sapiens. • Varietas ("Variety") - species variant, e.g. Homo

sapiens europaeus.

Section 3 Two Modern Systems of Classification

6-Kingdom Classification1. Archaebacteria autotroph/heterotroph2. Eubacteria autotroph/heterotroph3. Protista autotroph/heterotroph4. Fungi heterotroph5. Plantae autotroph/heterotroph6. Animalia heterotroph

Archaebacteria

• Unicellular• Live in extreme habitats• One of the first organisms to inhabit the Earth.Habitats: hot springs, salty lakes, swampsAnaerobic environments - without oxygenThermophiles – heat loversMethanogens – produce methane gasHalophiles – salt lovers

• Halophiles

• Thermophiles

Eubacteria

• Common bacteria• Most use oxygen; few cannot live in the

presence of oxygen.• Decomposers• Used in food making• Cause disease• Bioremediation – bacteria that eat oil spills

Shapes of Bacteria

• Cocci – round• Bacilli – rod• Spirilla – spiral

• Planes - staph• Chains – strepto

ex. Streptococcus

Classifying Bacteria

• Gram Staining• Procedure that stains bacteria.• Some bacteria stain pink other stain purple.• Gram stain positive – purple• Gram stain negative – pink• This tells scientists what kind of wall the

bacteria has. More peptidoglycan more rigid wall --- gram positive

• Gram positive

• Gram negative

Classifying Bacteria

• Agar – media that is used to grow bacteria.• Strict aerobe – grow only in the presence of

oxygen.• Strict anaerobe – grow only in the presence of

no oxygen.• Facultative anaerobe – prefer oxygen

environments but can grow throughout a medium.

http://upload.wikimedia.org/wikipedia/commons/9/90/Anaerobic.png

Classifying Bacteria

• Some can metabolism certain substances.• Lactose – bacteria can metabolize lactose.– Ex. Lactobacillus

Motile – some bacteria can move throughout a media.

Classifying Bacteria

• Differential media: Some shows different reactions.

• Selective media: Some can grow certain bacteria.

Viewing Microbes

• Resolution(seeing detail) can be increased using immersion oil.

• Allows the light ray to go directly through the objective lens.

Reproduction

• Binary Fission

Conjugation

• Bacteria gives its DNA to another bacteria.

Phylum Cyanobacteria

• Photosynthetic – use the sun’s energy to make food.

• Early atmosphere was filled with oxygen produced by cyanobacteria which allowed aerobic organisms to develop.

• Lack a membrane-bound nucleus like all bacteria.

• Enclosed with a jellylike case which help them cling together.

Cyanobacteria

Heterocysts

• Some Cyanobacteria grow in chains.• Some of the cells specialize – these cells are

called heterocysts.• Heterocysts contain enzymes for fixing

atmospheric nitrogen.• Make nitrogen available to plants in a form

that plants can use.• Nitrogen fixing bacteria

Eutrophication

• Some cyanobacteria like Anabaena thrive on phosphates and nitrates that accumjulate in a body of water.

• Sudden increase in the number of cyanobacteria due to a high availability of nutrients is called eutrophication or population bloom.

• Then cyanobacteria die and heterotrophic bacteria eat them.

• Their population increase which uses up a lot of oxygen in the water causing other organisms in the water like fish to die.

Phylum Spirochetes

• Gram-negative, spiral-shaped heterotrophic bacteria.

• Some are aerobic and some are anaerobic.• Move by means of a corkscrew-like rotation.• Some live freely, symbiotically, or parasitically.Ex. Treponema pallidum – causes the STD syphilis.

Phylum Gram-Positive Bacteria

• Not all members are gram-positive• Some gram-negative bacteria are grouped in

this phylum because they share molecular similarities with gram-positive bacteria.

Ex. Streptococci – causes strep throat Lactobacilli – found on teeth, known to cause tooth decay.

Actinomycetes

• Gram-positive bacteria• Form branching filaments• Grow in soil and produce many antibiotics.Antibiotics – chemicals that inhibit the growth

of or kill other microscopic organisms.

Phylum Proteobacteria

• Largest and most diverse phylum of bacteria.• Subdivisions: enteric bacteria,

chemoautotrophic bacteria, and nitrogen-fixing bacteria

Enteric Bacteria

• Gram-negative• Heterotrophic• Live in animal intestinal tracts.• Live in both aerobic and anaerobic environments.• Ex. E. coli• E. coli lives in the human intestine where it

produces vitamin K and assists enzymes in the breakdown of foods.

• Salmonella – food poisoning

Chemoautotrophs

• Gram-negative• Extract energy from minerals by oxidizing the

chemicals in these minerals.• Ex. Iron-oxidizing bacteria live in freshwater

ponds that contain a high concentration of iron salts. Bacteria oxidize the iron in the salts to obtain energy.

• Rhizobium nitrogen-fixing bacteria that live symbiotically with plants.

Rhizobium

• Pg. 473• Questions 1-6

Chapter 24 sec. 3

• Bacteria and Humans• Pathology – study of disease.• Bacteria cause disease by producing poisons

called toxins. – Exotoxins are toxins that are made of protein.– Exotoxins are produced by gram-positive bacteria

and are secreted into the surrounding environment.

– Ex. Tetanus is a disease caused by an exotoxin.

– Endotoxins – toxins made of lipids and carbohydrates. Made from the outer membrane of gram-negative bacteria, such as E.coli.

– Unlike exotoxins that are continually released by gram-positive bacteria; endotoxins are released when the gram-negative bacteria dies.

– Cause fever, body aches, and weakness, damage the vessels of the circulatory system.

Antibiotics• Drugs that combat bacteria

by interfering with various cellular functions.

• Ex. Penicillin interferes with cell wall synthesis.– Tetracycline interferes with

bacterial protein synthesis.– Many antibiotics come from

chemicals that bacteria and fungi produce.

– Antibiotics protect bacteria and fungi from other microscopic invaders.

Antibiotics

• Some antibiotics such as sulfa drugs are synthesized in laboratories.

• Many antibiotics are able to affect a wide variety of organisms; they are given the name broad spectrum antibiotics.

• Table 24-5 Common Antibiotics1. What drugs inhibits protein synthesis in bacteria?2. What drug inhibits DNA synthesis in bacteria and

what is this drug used to treat?

Antibiotic Resistance

• When a population of bacteria is exposed to an antibiotic the bacteria that are most susceptible to the antibiotic die first.

• A few mutant bacteria that are resistant to the antibiotic may continue to grow.

• Antibiotics have been overused so many diseases that were once easy to treat are becoming more difficult to treat.

Useful Bacteria

• Break down the remains of organic matter• Recycles carbon and nitrogen• Producing and processing food– Ferment lactose in milk to produce sour cream,

cheese, buttermilk, and yogurt– Sauerkraut– pickles

• Industrial chemical production• Bioremediation – cleaning up oil spills

HomeworkPg. 480 questions 1-6

Brochure Project• You will make an informational brochure about a

bacterial disease. You will use Microsoft Publisher. Let me know when you are ready to print!

• Include:– Gram positive or gram negative– Shape of bacteria– How one is contracted by this disease– How the disease is treated– Symptoms of the disease– Additional information (websites where one can get

more information)– 2 pictures (nothing too disgusting)

Disease to Choose From• Bacterial Meningitis tc• Lyme Disease bp• Botulism gd• Cholera kk• Rocky Mountain

Spotted Fever dm• Whooping Cough

(Pertussis) js• Tetanus sb

• Strep throat lh• Gonorrhea js• Tuberculosis ml• Salmonella vb• E.coli aw• Syphilis rc

Viruses

• Not living• Contain DNA or RNA and a protein coat.• Different shapes

Kingdom Protista

• Most are single-celled• Some are multi-cellular like kelp.• Protists are grouped:– Plant-like– Fungi-like– Animal-like