Classifying Organisms

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Classifying Organisms

• Chapter 6 Section 1
• Mrs. Kerstetter

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Why do Scientists Classify?

• Imagine a grocery store
• How are they organized?
• What would happen if they were not organized?
• How is your life organized?

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Why do Scientists Classify?

• Almost 2 million kinds of organisms on Earth
• Need to keep organized! (Easier to study!)
• Classification
• process of grouping things based on their
  similarities

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Why do Scientists Classify?

• Taxonomy
• scientific study of how living things are
  classified
• Useful because
• once classified, scientists will know a lot
  about an organism

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Early Classification Systems

• Aristotle (4th century B.C.)
• -observed animals
• -watched appearance, behavior, movement
• -fly, swim, and walk/crawl/run
• -observed similarities and differences
• -used differences to divide into smaller
  subgroups

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Linnaeus

• Carolus Linnaeus (1750s)
• -used observations as basis of his system
• -placed organisms based on observable features
• Devised naming system for organisms
• Binomial Nomenclature

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Linnaeus

• Binomial Nomenclature
• 2 part naming system
• -uses Latin words
• Genus species Felis concolor
• Genus is capitalized species is NOT.
• If you cant italicize, underline the genus and
  species!

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Classification Today

• Species with similar evolutionary histories are
  classified more closely together.
• -when organisms share a common ancestor, they
  share an evolutionary history

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Levels of Classification

• -based on contributions of both Aristotle and
  Linnaeus
• There are 7 levels of classification.
• Remember the first letter of this sentence
• King Philip Came Over For Good Spaghetti.

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7 Levels of Classification

• Kingdom broadest level
• Phylum
• Class
• Order
• Family
• Genus
• Species most specific

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Using the Classification System

• Field guides help identify organisms.
• -they highlight differences between similar
  organisms (like trees)
• Taxonomic Key (AKA Dichotomous Key)
• -paired statements that describe the physical
  characteristics of different organisms

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Taxonomic Key

• 1. Fruits occur singly ...........................
  ............................ Go to 3
• 1' Fruits occur in clusters of two or more
  ......................... Go to 2
• 2. Fruits are round ..............................
  ......................... Grapes
• 2' Fruits are elongate ...........................
  ........................ Bananas
• 3. Thick skin that separates easily from flesh
  .............Oranges
• 3' Thin skin that adheres to flesh
  .............................. Go to 4
• 4. More than one seed per fruit
  ............................ Apples
• 4' One seed per fruit ............................
  ................ Go to 5
• 5. Skin covered with velvety hairs
  .................... Peaches
• 5' Skin smooth, without hairs ....................
  ....... Plums