Classifying Living Things

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Classifying Living Things

• 7-1

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Living organisms are everywhere!

• Scientists have made observations about the world
  for 1000s of years
• Communication was very poor
• A universal system of classification was necessary

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The Greeks

• The Greek society was full of scholars and
  scientists.
• Aristotle was the first scientist to begin
  classifying organisms
• He observed their
• appearance and behavior.

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How did Aristotle begin to classify ?

• With Blood
• Vertebrates
• Life bearing
• Egg bearing

• Aristotle classified
• organisms into distinct
• groups

• Without blood
• Invertebrates
• Insects such as crustaceans

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• He thought of a classification system that he
  called the Ladder of Life
• This very simple chart included 11 degrees of
  life
• The first being plants and the last being humans!
  

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• Classification is the process of arranging
  organisms into groups based on their similarities

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• Taxonomy is the science of naming and classifying
  organisms
• A good system of taxonomy allows people to
  communicate about organisms
• Before 1700 scientists had not agreed on a system
  of naming and grouping
• Latin was the universal language choice for
  naming organisms because the language was no
  longer being used

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Taxonomy

• The science of Taxonomy is related to the Greek
  word taxis which means arrangement
• Taxonomists are the scientists who classify and
  name organisms based on their similarities and
  differences
• Taxonomists study the relationships of species
  and compare them with other species

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• Taxonomists can also classify organisms according
  to their traits
• A trait is a characteristic or behavior that can
  be used to tell two species apart

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Evidence for Classification

• Physical what the organism looks like. What
  you can see with your eyes using direct
  observation .
• This type of observation helps scientists link
  species with evolution

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Physical Evidence

• Are these locusts
• the same?
• What makes them
• Different?
• What is similar about
• them?

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• Cyanocitta c.cristata
• Turdidae sialia
• The class is still Aves!

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• Genetic The use of laboratory machines to
  analyze DNA to link species on a cellular level
• Usually supports physical evidence.

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The Seven Levels of Classification 7-2

• Carolus Linnaeus developed systems for both
  naming species and organizing them into groups
• He named 4000 species!

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The 7 levels of classification

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species
• The largest group of species in this
  classification system is Kingdom

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• A group of species that have similar
  characteristics is a genus
• Members of the same genus are very closely
  related.
• Genus Felis

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• Linnaeus used Binomial Nomenclature to name
  species
• Binomial means two names
• Nomenclature means list of names

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Writing the names of species

• When writing names of organisms in scientific
  classification, the genus is written in italics
  and capitalized and the species is written next
  and is lowercase.
• Chameleo gracilis

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So what would a dog be??

• Kingdom- Animalia
• Phylum- Chordata
• Class-Mamalia
• Order-Carnivora
• Family- Canidae
• Genus- Canis
• Species- C.lupus
• Canis c-lupus

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What about this??

• Canis rufus
• (Red Wolf)

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Tools of Classification

• A Dichotomous Key and Field Guides can be used to
  classify organisms easily

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Dichotomous Key

• Asks a series of questions that can only be
  answered in one of two ways
• Each answer leads to another question till you
  get the organism you need to identify

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Field Guides

• Field Guides use pictures or illustrations to
  identify organisms based on their physical
  characteristics

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Classification systems change as scientists learn
more

• Chapter 7-3

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• Species continue to grow as scientists discover
  new organisms or species. The scientific
  community are also learning new things about
  evolution and genetic make-up of species

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New level of classification!

• The new level of classification that has been
  added to the system is Domain
• These are larger groupings that contain 3 levels
  on a cellular level

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• These Domains are Bacteria, Archea, and Eukarya
• Bacteria and Archea contain only organisms
  without a nucleus
• Eukarya are organisms with a nucleus and can be
  either unicellular or multi- cellular

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Bacteria

• Unicellular
• No nucleus
• Reproduce by cell division

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Archaea

• Unicellular
• Different chemicals than bacteria and are older
• Live in extreme conditions

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Protista

• Multi cellular
• Has a nucleus
• Contain the hard to place organisms

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Fungi

• Multi cellular
• Decompose other organisms
• Has a nucleus

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Plantae

• Multicellular
• get energy from the sun
• has a nucleus and a cell wall

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Animalia

• multi cellular
• eat food for energy
• have a nucleus

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Test on Monday!!!