Scientific Classification

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Scientific Classification

• Whats In a Name??

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What are some ways you are classified?

• gender
• age
• social security number
• income
• state/area of residence
• profession

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Why Classify??

• Human nature- we love to put things in their
  place!
• Organization
• Identification
• Less Confusion
• Show Relationships

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Modern Classification

• Linnaeus
• Binomial nomenclature
• Taxon (taxa)
• phylogenetics- the tracing of evolutionary
  relationships

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Early history of life

• Solar system 12 billion years ago (bya)
• Earth 4.5 bya
• Life 3.5 to 4.0 bya
• Prokaryotes 3.5 to 2.0 bya stromatolites
• Oxygen accumulation 2.7 bya photosynthetic
  cyanobacteria
• Eukaryotic life 2.1 bya
• Muticelluar eukaryotes 1.2 bya
• Animal diversity 543 mya
• Land colonization 500 mya

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Bacteria

• Kingdom Monera?
• Domain Bacteria
• Domain Archaea
• Prokaryotic- no membrane-bound organelles,
  microscopic
• Shape
• cocci (sphere)
• bacilli (rod)
• helical (spiral)

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Archaea Vs. Eubacteria

• Domain Archaea
• no membrane- bound organelles (prok.)
• no peptidoglycan
• do not respond to antibiotics
• extremophiles
• chemoautotrophs, heterotrophs
• 3 main groups methanogens, extreme halophiles,
  extreme thermophiles

• Domain Eubacteria
• no membrane-bound organelles (prok.)
• peptidoglycan in cell walls
• growth inhibited by antibiotics
• diverse metabolism
• 5 main groups spirochetes, chlamydias, gram,
  cyanobacteria, proteobacteria

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Prokaryotes

• Decomposers unlock organics from corpses and
  waste products
• Symbiosis symbiont/host mutualism (, )
  parasitism (, -) commensalism (, 0)
• Disease opportunistic normal residents
  of host cause illness when defenses are weakened
  Kochs postulates criteria for
  bacterial disease confirmation
• exotoxins bacterial proteins that can produce
  disease w/o the prokaryote present (botulism)
  endotoxins components of gram -
  membranes (Salmonella)

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Enter Eukaryotes- Domain Eukarya

• nucleus
• membrane-bound organelles
• larger in size than prokaryotic cells
• fungus, plant, and animal cells

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Kingdom Protista (Domain Eukarya)

• Ingestive (animal-like) protozoa
• Absorptive (fungus-like)
• Photosynthetic (plant-like) alga

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Kingdom Plantae (Domain Eukarya)

• bryophytes (mosses), pteridophytes (ferns),
  gymnosperms (pines and conifers) angiosperms
  (flowering plants)
• Plants multicellular, eukaryotic,
  photosynthetic autotrophs
• Terrestrial colonization
• Vascular tissue
• The seed
• The flower

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Gymnosperms (Kingdom Plantae)

• Cone-bearing plants
• Lack enclosed chambers (ovaries) for seeds
• Ovules and seeds develop on specialized leaves
  called sporophylls
• Ginkgo, cycads, and conifers
• All are evergreens
• Needle-shaped leaves
• Vascular tissue refinement tracheids water
  conducting and supportive element of xylem

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Angiosperms (Kingdom Plantae)

• Most diverse and geographically widespread of all
  plants
• Flowering plants(Phy Anthophyta)
• Monocots 1 embryonic seed leaf (lilies, palms,
  grasses, grain crops)
• Dicots 2 embryonic seed leaves (roses, peas,
  sunflowers, oaks, maples)
• Vascular tissue refinement vessel elements/fiber
  cells

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Kingdom Fungi (Domain Eukarya)

• Heterotrophic by absorption (exoenzymes)
• Decomposers (saprobes), parasites, mutualistic
  symbionts (lichens)
• Hyphae body filaments
  septate (cross walls)
  coenocytic (no cross walls)
• Mycelium network of hyphae
• Chitin cell walls (polysaccharide)

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Fungi Diversity, I

• Phy Chytridiomycota aquatic fungi chytrids
  lineage closest to protists
  (flagella)
• Phy Zygomycota Rhizopus (food mold)
  mycorrhizae mutualistic with plant roots
  zygosporangia resistant structure (freezing
  and drying)

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Fungi Diversity, II

• Phy. Ascomycota sac fungi
  yeasts, truffles, morels, Sordaria
  asci sexual spores
  conidia asexual spores
• Phy. Basidiomycota club fungus
  mushrooms, puffballs, shelf fungus, rusts
  basidiocarps produce sexual spores

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Kingdom Animalia (Domain Eukarya)

• heterotrophic
• most are mobile
• ingestion followed by digestion
• multicellular (most have tissues)
• lack cell walls
• sexual reproduction
• 35 phyla- most are marine

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Animal phylogeny diversity

• Monophyletic colonial flagellated protist
  ancestor
• 1- Parazoa-Eumetazoa dichotomy sponges
  (Parazoa) no true tissues all other animals
  (Eumetazoa) true tissues
• 2- Radiata-Bilateria dichotomy Cnidaria (hydra
  jellyfish sea anemones) Ctenophora (comb
  jellies) radial body symmetry all other
  animals bilateral body symmetry (also
  cephalization)

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Summary

• 3 Domains- but textbooks are behind Bacteria,
  Archaea, and Eukarya
• 6 kingdom system in most texts Eubacteria,
  Archaea, Protista, Fungi, Plantae, Animalia
• classification now based on evolutionary history