CO3

• Nomenclature

  Formal means of naming organisms (binomial nomenclature)
• Taxonomy

  1. Naming, describing, and classifying organisms

  2. List of features or attributes of a certain taxon

  3. Associating an unknown organism or taxon with a known one
• Three Domains of Life Distinction

  • Bacteria
  • Archaea
  • Eukarya
• Genus name can be abbreviated to just the initial after the first mention if the context is clear
• Linnaean Classification System

  Carolus Linnaeus is the father of modern taxonomy who formalized binomial nomenclature
• Systematics


  • Provides scientific names for organisms
  • Describes organisms
  • Provides identification classification for organisms
  • Investigates evolutionary species
  • Environmental adaptations
• Binomial Nomenclature

  1. A species is referred to by the full binomial name (Genus species)

  2. Genus is a taxonomic rank used in hierarchy, which refers to the group of species that are closely related and share common characteristics

  3. Specific epithet pertains to one species within its genus

  4. Scientific names should be either italicized or underlined

  5. Genus name is always written with an initial capital letter

  6. Species epithet is always written in lowercase
• DNA Barcoding

  1. Compares a short fragment of DNA sequence from an unknown organism to a large database of sequences from known organisms

  2. DNA is the UPC of organisms on Earth

  3. A DNA barcoding device would provide a fast and inexpensive way to catalog organisms
• Classification

  Ordered grouping of organisms
• Three-Domain System

  1. Carl Woese compared nucleotide sequences of rRNA of prokaryotes and eukaryotes, suggesting that all organisms evolved along three distinct lineages

  2. Domain Bacteria consists of prokaryotic unicellular organisms that reproduce asexually

  3. Domain Archaea consists of prokaryotic unicellular organisms that reproduce asexually and live in extreme environments

  4. Domain Eukarya includes unicellular and multicellular organisms with membrane-bound organelles
• Three domains of life distinction

  • Bacteria
  • Archaea
  • Eukarya
• Tree diagram explanation

  • Base represents a hypothetical common ancestor, organisms at the tips represent living descendants, branches represent reproductive lineages and how they split over time, branch points or nodes represent common ancestors
• Cladogram construction

  • Step 1: Make a table with organisms and characters, Step 2: Mark the traits that fit, Step 3: Determine the ancestral character, Step 4: Identify derived traits shared, Step 5: Draw the cladogram
• Cladistics


  • Method using shared, derived traits to develop a hypothesis of evolutionary history, clade includes an ancestor species and all its descendants, cladogram interprets evolutionary history of derived traits
• Evolutionary history is the study of constructing the evolutionary history of a group of organisms by identifying shared, heritable traits that evolved in a common ancestor
• Derived traits

  • Present in some members of a group, but absent in the common ancestor; important for clarifying evolutionary relationships
• Nucleus

  • Enclosed in a nuclear envelope for storage of genetic material
• Phylogenetic tree


  • Branching diagram showing evolutionary history of a group of organisms, each branching point represents a divergence from a common ancestor
• Relatedness


  • Connections to common ancestors indicate which creatures are more closely related, organisms with more characteristics in common share a more recent common ancestor
• Characteristics of Bacteria, Archaea, Eukarya

  • Unicellularity
  • Membrane lipids
  • Cell wall
  • Nuclear envelope
  • Membrane-bounded organelles
  • Ribosomes
  • Introns
• Ancestral traits


  • Present in all members of a group, present in the common ancestor
• Constructing a cladogram

  Make a table with organisms and characters, mark traits that fit the organisms, determine ancestral character, identify derived traits shared by organisms, draw the cladogram