Chapter 17 Classification

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Chapter 17Classification

• Section 17-1 History of Taxonomy

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Taxonomy is the branch of biology that names
organisms according to their characteristics and
evolutionary history
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Taxonomy organizes the huge biodiversity (variety
of types of life) of the planet
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• Organisms were first classified by Aristotle over
  2000 yrs ago!
• His system classified organisms as either plant
  or animal.
• Problems with his classification
• Some organisms are neither plant or animal
• Common names are different in different regions
  (ex. Puma, cougar, and mountain lion are all same
  animal
• Some common names are
• inaccurate (ex. Jellyfish is not a
• fish, seahorse is not a horse)

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Carolus Linnaeus developed a more organized
system of classification in the 1700s

• This system involves seven levels of
  classification which are still used today

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Levels of classification

• Memory device
• King
• Phillip
• Came
• Over
• For
• Good
• Spices

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

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Some examples (pg. 338)
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Some examples (pg. 338)
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Linnaeuss system for naming

• The system is known as binomial nomenclature (bi-
  means 2)
• Each species is identified by two names genus
  and species.
• Genus is capitalized the species is not and both
  are written in italics
• Ex Lynx rufus and Homo sapiens

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Section 17-2 Modern Phylogenetic Taxonomy
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• Classification originally based on morphology
• Modern taxonomists use this and other evidence to
  place organisms on a phylogenetic tree
• A phylogenetic tree is a diagram showing
  evolutionary relationships of organisms

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4 Types of Evidence Help Scientists make a
Phylogenetic Tree
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Evidence

• Morphology, or the appearance of an organism.

Related organisms will share homologous
structures
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Evidence

• 2. The fossil record
• Some fossils serve as links in connecting
  current groups of organisms.
• EX archaeopteryx

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Evidence

• 3. Embryological patterns of development
• By looking at the stages of an organisms
  development scientists can see patterns.
• Ex all fertilized animal eggs begin to grow in
  the same way
• Zygote ? blastula ? gastrula (read pg 344)

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Evidence

• Comparing the number of differences in DNA, amino
  acids and proteins
• If mutations in sequence occur regularly
  scientists can predict how closely related
  organisms are. The more similar the DNA the more
  closely related the species.

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Cladistics

• A new system of phylogenetic classification.
• It uses a shared derived characteristic to
  establish relationships
• Ex amniotic (shelled) egg separates reptiles and
  birds from other organisms or hair on mammal

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How to read a cladogram
Everything else has jaws
No jaws
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Section 17-3 Two Modern Systems of Classification
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Two main systemsThree Domain and Six Kingdom
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Kingdom Archeabacteria

• Unicellular (one-celled)
• Prokaryotic (no nucleus)
• Chemosynthetic (use
• carbon chemicals to make energy)
• They have different cell membranes than other
  organisms
• They often live in harsh environments

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Kingdom Eubacteria

• Unicellular
• Prokaryotic
• Most use oxygen for
• respiration
• These are true bacteria involved in decomposing
  dead animals and plants, making yogurt, etc.

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Kingdom Protista

• Unicellular
• Eukaryotic (has nucleus)
• Can be autotrophic (make food or heterotrophic
  (eat food)
• Although in the same kingdom there is a huge
  variety all very distantly related

Ex amoeba and euglena
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Kingdom Fungi

• Multicellular AND UNICELLULAR! oops
• Eukaryotic
• They are heterotrophic (eat food) specifically
  they absorb food.
• Common fungi Yeast mushrooms

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Kingdom Plantae

• Multicellular
• Eukaryotic
• Autotrophic - Plants use solar energy to
  photosynthesize or make food
• Most plants live on land and reproduce sexually
• Ex venus fly trap oak tree

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Kingdom animalia

• Multicellular
• Eukaryotic
• Heterotrophic (eat food)
• Can live on land or water.
• Reproduce sexually
• Ex. Coral elephant