2The classification of organisms The problem with common namesDifferent in every languageDifferent names can be used to identify the same organism.Organisms must have names that all scientists can identify.Naming organisms involves two different activities.TaxonomyThe naming of organismsPhylogenyDemonstrating how organisms are related evolutionarily
3Garden snake or Garter snake?Jamestown or Jimson weed? Then in 1676, British soldiers were sent to stop the Rebellion of Bacon. Jamestown weed (jimson weed) was boiled to be included in a salad for the soldiers to eat. The hallucinogenic properties of jimsonweed took affect.
4TaxonomyThe science of naming organisms and grouping them into logical categoriesTaxis=arrangement Taxon a groupingScientific names of organisms are in Latin.Capparis cynophallophora, means “dog-penis bearing caper
5Taxonomy Organism names follow the binomial system of nomenclature. Introduced by LinnaeusUses two Latin namesThe genus and the specific epithetA genus is a group of closely related organisms.A specific epithet identifies the particular species to which the organism belongs.Binomial names are italicized or underlined.The first letter of the genus is capitalized; the specific epithet is not.Thamnophis sirtalis Cattus domesticus Homo sapiens Capparis cynophallophora
6Taxonomy Organisms are organized into logical groups. These groups are hierarchical.Domain, kingdom, phylum, class, order, family, genus, speciesDKPCOFGS
9PhylogenyThe science that explores the evolutionary relationships among organisms.Seeks to reconstruct evolutionary history.Phylogenists use a variety of data to establish evolutionary relationships.FossilsComparative anatomy studiesLife cycle informationBiochemical and molecular studies
10Fossils Fossils can be placed in a time sequence. Established by the order that the organisms appear in the layers of sediment.Deeper layers were laid down first.Rocks can be aged by analyzing radioactive isotopes.Older rocks have fewer radioactive isotopes.
11Comparative anatomy studies The anatomy of fossilized organisms can be compared to that of living organisms.Allows for the classification of fossilsThose organisms that have similar structures are presumed to be related.Ontogeny recapitulates phylogenyExamplesPlants with flowers are related.Animals with hair and mammary glands are related.
12Biochemical and molecular studies New DNA technologies have allowed phylogenists to use DNA sequence comparisons to determine relatedness.
14A brief survey of the domains of life Eubacteria, Archaea and EuKaryaEubacteria and Archaea are prokaryotic.eukarya is eukaryotic.
15Domain Eubacteria “True bacteria” Unicellular Small (1-10 mm) Prokaryotic (no nucleus)Contain a single, circular chromosomeReproduce asexually
16Domain eubacteria Cell walls made of peptidoglycan Can be rods, spheres or spiralsVaried metabolic requirements
17Domain Archaea Unicellular Prokaryotic Single circular chromosomesHave significant differences from both eubacteria and eukaryaNo peptidoglycan in their cell wallsLive in extreme habitats
18Domain archaea Metabolically labeled as extremophiles Methanogens Produce methaneFound in sewage, guts of ruminants, intestines of humansHalobacteriaLive in extremely salty environmentsPhotosyntheticThermophilesLive in high temperatures or areas with high sulfur concentrations
20Domain Eukarya Eukaryotic Appear to have evolved through endosymbiosis of prokaryotic cellsLarger than prokaryotesContain specialized membranous organelles
21Kingdom protista Most are unicellular. Diverse Some form colonies.Diverse60,000 speciesLive in freshwater, marine, terrestrialSome are parasitic, commensalistic or mutualistic.Include algae, protozoa and slime moldsAmoeba, Paramecium
23Kingdom fungi Most are non-motile Have a thin, rigid cell wall composed of chitinHeterotrophicMost are saprophytes (saprotrophic) that secrete enzymes that break down the material they live on.DecomposersSome are parasitic, others are mutualistic.Can form lichens
24Kingdom fungi Most are multicellular. Made up of filaments Include A few are unicellular.YeastMade up of filamentsIncludeAthlete’s footPlant pathogensRingworm
31Acellular infectious particles Living organisms are made of cells.Have cell membranesUse nucleic acids as genetic materialHave cytoplasmContain enzymesContain ribosomesUse ATP as their source of energyParticles that show some of these characteristics, but not all, are called acellular.Most of these cause disease.Viruses, viroids and prions
32VirusesAn infectious particle consisting of a nucleic acid core surrounded by a coat of protein.Are obligate intracellular parasitesBecause they cannot live outside of a living cellNot technically “living”Are extremely small.
35How viruses cause disease Viruses must get their nucleic acids into the cell.Take over host cell to make more virus
36How viruses cause disease Viruses don’t have many enzymes.They depend on their hosts to replicate their DNA and make their proteins.After viruses are replicated they leave the cell.Frequently, this process kills the cell.
38Prions: Infectious proteins All prion diseases cause brain tissue to become “spongy”.Cause spongiform encephalitisMad cow (BSE), scrapie (sheep), Creutzfeld-Jakob and Kuru (human)Can be transmitted from one animal to another