Biological Classification

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Biological Classification

• Chapter 18

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Finding Order in Diversity

• To study the diversity of life, biologists use a
  classification system to name organisms and group
  them in a logical manner.

Tacitus bellus

• Taxonomy is the branch of biology that groups and
  names organisms based on studies of their
  different characteristics.

• Biologists who study taxonomy are called
  taxonomists.

• Classification systems change with expanding
  knowledge.

Populus tremuloides Quaking Aspen
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Carolus Linnaeus

• Swedish botanist
• Developed Binomial Nomenclature
• Two-word naming system
• Genus
• Noun, Capitalized, Underlined or Italicized
• Species
• Descriptive, Lower Case, Underlined or
  Italicized
• Each species is assigned a two-part scientific
  name
• Exp. Ursus arctos

Carolus von Linnaeus(1707-1778) Scientist who
laid foundation for modern taxonomy
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System of Classification

• Linnaeuss hierarchical system of classification
  includes seven levels (from largest to smallest)
• Grizzly Bear (common name)
• Kingdom Animalia
• Phylum Chordata
• Class Mammalia
• Order Carnivora
• Family Ursidae
• Genus Ursus
• Species arctos

Each of the levels is called a TAXON
Ursus arctos (scientific name)
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System of Classification

• Taxonomic categories
• Kingdom King
• Phylum Philip
• Class Came
• Order Over
• Family For
• Genus Good
• Species Soup

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Evolutionary Classification

• Phylogeny evolutionary relationships among
  organisms
• Evolutionary classification strategy of
  grouping organisms together based on their
  evolutionary history

• Fossil record
• Comparative homologies
• Comparative sequencing of DNA/RNA among organisms
• Molecular clocks

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Taxonomic Diagrams
Mammals
Turtles
Lizards and Snakes
Crocodiles
Birds
Cladogram
Attempt to trace the process of evolution by
focusing on shared features
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Dichotomous Keys Identify Organisms

• Dichotomous keys contain pairs of contrasting
  descriptions.
• After each description, the key directs the user
  to another pair of descriptions or identifies the
  organism.
• Example 1. a) Is the leaf simple? Go to 2 b)
  Is the leaf compound? Go to 3
• 2. a) Are margins of the leaf jagged? Go to
  4 b) Are margins of the leaf smooth? Go to 5

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Kingdoms and Domains

• Domain
• Most inclusive category
• Larger than a kingdom
• There are 3
• Eukarya includes the kingdoms
• Protists, Fungi, Plants Animals
• Bacteria corresponds to the kingdom Eubacteria
• Archaea corresponds to the kingdom
  Archaebacteria

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Kingdoms

• Monera (Eubacteria and Archaebacteria) -
  Prokaryotes, with or without peptidoglycan in
  cell walls
• Protista Eukaryotes, diverse, not fungi,
  plants, or animals
• Fungi Eukaryotes, multicellular (except
  yeasts), heterotrophic, chitin in cell walls
• Plantae Eukaryotes, multicellular, autotrophic,
  cell wall containing cellulose
• Animalia Eukaryotes, multicellular,
  heterotrophic, no cell wall

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The Kingdom Monera - Eubacteria

• Common name Bacteria
• Unicellular prokaryotes
• Peptidogylcan in cell wall
• Ecologically diverse
• Basic shapes are cocci, bacilli, spirilla
• Reproduce both sexually and asexually

Streptococcus mutans (can cause endocarditis and
dental caries)
Bacillus anthracis (spores can live in soil for
years)
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The Kingdom Monera - Archaebacteria

• Cell wall does not contain peptidogylcan
• Cell membrane contains unusual lipids not found
  in other organisms
• Live in extreme environments (devoid of oxygen)
• volcanic hot springs
• brine pools
• black organic mud

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The Kingdom Protista

• A classification problem consists of organisms
  that cannot be classified as animals, plants, or
  fungi
• Most unicellular, some colonial and some
  multicellular
• Autotrophic and heterotrophic
• Some move with flagella, pseudopods or cilia
• Animal-like, plant-like and fungus-like groups
• Reproduce by mitosis and meiosis

Entamoeba histolytica
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The Kingdom Fungi

• Most feed on dead of decaying organic matter by
  secreting digestive enzymes into their food
  source then absorbing it into their bodies
• Cell walls of chitin
• Most multicellular some
  unicellular
• Heterotrophic

Boletus zelleri (Edible, but often infected with
fly larvae)
Epidermophyton floccosum (one of the causes of
athlete's foot)
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The Kingdom Plantae

• Multicellular
• Nonmotile cannot move from place to place
• Cell wall with cellulose
• Mostly photosynthetic autotrophs

Sunflowers in Fargo, North Dakota
Ginkgo biloba Ginkgos are often very long-lived.
Some specimens are thought to be more than 3,500
years old.
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Kingdom Animalia

• Multicellular
• Heterotrophic
• No cell walls or chloroplasts
• Incredible diversity

Colony of sponges
Hymenoptera Dialictus zephrum
Chambered Nautilus
Txodes scapularis Deer tick
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Hierarchical System of Classification
From general to more specific
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6 Kingdoms
How many Kingdoms?