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Taxonomy. The modern science of taxonomy began in the mid 18 th cent. founded by Carolus Linnaeus Taxonomy: Identifying, naming and classifying of organisms. Systematics: Science dealing with the relationship of organisms to one another.
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Taxonomy • The modern science of taxonomy began in the mid 18th cent. • founded by Carolus Linnaeus Taxonomy: Identifying, naming and classifying of organisms. Systematics: Science dealing with the relationship of organisms to one another. Phylogeny: The evolutionary history of an organism and its relationship to other species.
Cladistics • Phylogenetic tree is constructed using traits that have been inherited from a common ancestor. • Organisms related by descent are called a clade. • Derived characters: Jaws Lungs Amniotic membrane Hair No tail Bipedal
Phylogenetic Tree from Cladistics Sequence of branching implies order that new traits evolved Most likely hypothesis based on existing evidence
Traditional Taxonomy • Domain (Super kingdom) • Kingdom • Phylum • Class • Order • Family • Genus • Species
Binomial System • Linnaeus proposed a two name Latin system for classification. • Genus: A group of very similar organisms related by common descent from a recent ancestor and sharing similar physical traits. • Species: A specific kind of organism in a genus. A group within a genus that share the same set of structural traits and can successfully interbreed with one another. • Genus and species are italicized with genus capitalized.
Canis familiaris Domain: Eukaryota Kingdom: Animalia Phylum:Chordata Class: Mammalia Order: Carnivora Family: Canidae Genus: Canis Species: familiaris Common name: Dog
Classifying organisms: Linnaeus: 2 kingdom- Plantae and Animalia Whittaker: 5 kingdom- Monera, Protista, Fungi, Plantae and Animalia Woese: 6 kingdom- Bacteria, Archaea, Protista, Fungi, Plantae and Animalia Woese (1996): 3 domain- Bacteria, Archaea and Eukarya
Prokaryotes and Protists Chapter 16
Organismal Domains Prokaryotes Eukaryotes • 1-5 um in size • 10X’s more biomass • Wider range of environments • Greater diversity • Single, circular chromosome • Best known as bacteria • Disease causing agents are pathogens • Can live without the other • 10-100 um in size • Membrane bound nucleus and organelles • DNA arranged on multiple chromosomes • Can’t live without prokaryotes
Prokaryotic Shape • Cocci • Spherical and occur in chains or clusters • E.g. streptococcus and staphylococci • Bacilli • Rod shaped and occur singularly, in pairs, or chains • E.g. soil organisms • Various shapes • Vibrios resemble commas • Spirilla are short, rigid helical shapes • Spirochetes are longer, more flexible
Prokaryote External Structure • Cell wall • Bacteria can be gram (+) or gram (-) • (+) simple walls with thicker peptidoglycan (sugar polymer) • (-) more complex walls with less peptidoglycan • Lipids and carbs too that make them more threatening, toxic, and resistant to antibiotics • Capsule • Sticky polysaccharides or proteins to adhere to substrates • Pili • Hairlike appendages for adhesion
Prokaryotic Structure • Motility • Flagella • Naked protein structure w/o microtubules that moves in a propeller-like motion • Reproduction and adaptation • Divide by binary fission • Speed varies from hours to minutes • Limited by nutrients, competition, predation, and waste build up • Internal Organization • Small genetic rings that aid in resistance called plasmids • Smaller ribosomes • Wide range of methods to obtain nutrients
Prokaryotic Nourishment • Biofilms • Surface coating colonies of prokaryotes • Can be 1 or more species • E.g. dental plaque, UTI’s, or sewer treatment
Archaea • Live where other organisms can’t survive • Extreme halophiles • Salt environments • E.g Great Salt Lake, Dead Sea, or sewater evaporating ponds • Extreme thermophiles • Very hot water • E.g ocean vents, or acidic conditions • Methanogens • Anaerobic environments with methane as a waste product • E.g. swamps and GI tracts of animals
Bacterial Types • 9 groups • Proteobacteria • Gram negative • Gram positive • Chlamydias • Spirochetes • Cyanobacteria
Proteobacteria • Alpha (α) • Live in root nodules to fix atmospheric nitrogen • Foreign DNA carriers into crop plant genomes • Gamma (γ) • Photosynthetic • Inhabit animal intestines • E.gSalmonella, Vibriocholerae, and Escheria coli • Delta (δ) • Slime secreting myxobacteria • Can form fruiting bodies for selves when food is scarce • Attacks other bacteria
Actinomycetes • Gram Positive Bacteria • Form colonies of branched chains of cells or are solitary • Found in the soil • Streptomycin • cultured by pharmaceutical companies, • Bacillus anthracis • Form endospores, cell within a cell that dehydrates and lies dormant till more favorable conditions exist • Staphylococcus and streptococcus • Mycoplasmas • Lack cell walls • Tiniest of all known cells
Other Bacterial Phyla • Chlamydias • Live inside eukaryotes • Common cause of blindness (developing countries) and most common STD (United States) • Spirochetes • Spiral through environments by rotating internal filaments • E.gTreponemapallidum(syphilis) and Borreliaburgdorferi(Lyme disease) • Cyanobacteria • Oxygen-generating photosynthesis (only bacteria) • Food for freshwater and marine ecosystems
Bacterial Poisons • Exotoxins are proteins secreted by bacteria • Can exist in the bacteria • Clostridium tetani produces muscle spasms (lockjaw) • Staphylococcus aureuscommon on skin and in nasal passages • Produces several types causing varying problems • Acquired from genetic transfer between species • E. coli benign resident of intestines • Acquires genes that produce harmful effects • Endotoxins are components of gram (-) outer membranes • Released when cell dies or digested by defensive cell • Cause same general symptoms • Neisseriameningitidis(bacterial meningitis) and Salmonella (typhoid fever)
Disease Control • Improvements in sanitation • Water treatment and sewer systems • Antibiotic development • Increase in bacterial resistance • Education • Importance of seeking treatment • Prevention • Biological weapons
Biological Weapons • Inhalation anthrax (Bacillus anthracis) • Manufacture endospores to disperse into air • Once in lungs they multiply and produce exotoxins • Antibiotics kill the bacteria but can’t eradicate from body • Pnemonic plague (Y. pestis) • Airborne as lung tissue is coughed up • Botulinumexotoxin (C. botulinum) • Deadliest poison on earth • Blocks transmission of nerve signals for muscle contraction • Limited availability of antitoxin
Bioremediation • Use of organisms to remove pollutants • Prokaryotic decomposers major force in sewage treatment • Solid sludge from filters added to anaerobe colonies • Transformed into use for fertilizer or landfill • Liquid waste over biofilms remove organic material • Released into bodies of water • Oil spill and mining site clean up
Protists • Structure • Membrane bound nucleus with chromosomes • Other organelles characteristic of eukaryotes • Flagella and cilia in a 9+2 microtubule arrangement • Unicellular (most) • Most found anywhere there’s water • Several arose from secondary endosymbiosis • Symbiosis is a close association between 2 or more species • Endosymbiont is a species that lives within another species
Diplomonads • Heterotrophic • Possibly most ancient lineage • No DNA or electron transport chain • Anaerobic • E.g Giardia intestinalis • Parasite which derives nutrition from living hosts that are injured by it • Waterbourne parasite often ingested from fecal contaminated water
Parabasalids • Heterotrophic • Some energy anaerobically • E.g Trichomonas vaginalis • Travels through reproductive tract • Males and females can be affected, but male symptoms less common • Metronidazole only treatment currently • Resistance is increasing
Euglenozoans • Crystalline rod inside the flagella • Can be heterotrophs, photoautotrophs, and pathogenic parasites • E.g Trypanosoma • Causes sleeping sickness • Spread by African tsetse fly • E.g Euglena • Common in pond water
Alveolates • Membrane-enclosed sacs below the plasma membrane • Stabilize cell surface or regulate and ion content • Dinoflagellates • Marine and fresh phytoplankton • Red tide blooms, toxins kill fish and can affect humans • Ciliates • 2 types of nuclei, 1 for daily activities and 1 for reproduction • E.g Paramecium or Stentor • Apicomplexans • Parasites of animals • E.g Plasmodium which causes malaria
Amoebozoans • Move and feed by lobe shaped pseudopodia, temporary extensions of the cell • Parasitic amoebas • Cause dysentery • Slime molds • Organisms found in moist, decaying matter • Spread under favorable conditions, form spore producing structures under less favorable ones • Plasmodium, single multinucleated mass of cytoplasm • Cellular slime molds, solitary until food is scarce
Foraminiferans and Radiolarians • Move and feed by thread like psuedopodia • Forams • Marine and fresh water organisms • Have porous shells of CaCO3 called tests • Psudopodia extend through • Radiolarians • Marine • Internal shell of silica and outer test
Stramenopiles • Multiple ‘hairy’ flagella and a single ‘smooth’ flagellum • Water molds • Decompose dead plants and animals • Can be parasitic (Ireland potato famine) • Diatoms • Glassy cell wall of silica • Fresh and marine organisms • Brown algae • Autotrophic • Commonly called seaweed