Chapter 15 Classifying Living Things

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Chapter 15 Classifying Living Things

• High School Biology Class

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What is Classification?

• The branch of science that names and groups
  living organisms into categories based on their
  similar characteristics and evolutionary history.
• Sometimes referred to as taxonomy.

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Why is Classification Important?

• Every year, thousands of new species are
  discovered.
• Scientists have identified more than 2 million
  species of organisms, but estimate 40 million
  species inhabit the Earth.
• Scientists estimate that there may be millions of
  species in the tropical rain forest and an
  unspecified number living in the oceans currently
  undiscovered.

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Why is Classification Important?

• A Universal System is necessary to have clear
  communication among scientists worldwide.
• The system was designed to eliminate the use of
  common names and confusion in the scientific
  world.

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When Was Classification Started?

• Organisms were first classified more than 2,000
  years ago by the Greek philosopher Aristotle. 
• He classified things as either Plant or Animal.
• He grouped animals into three basic categories
  Land Dwellers, Water Dwellers, and Air Dwellers.
• He also grouped plants into three categories,
  based on differences in their stems.

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When Was Classification Started?

• As science developed and more was learned about
  living things Aristotle's system was very
  INADEQUATE.
• In the mid-100s Carols Linnaeus, a Swedish
  biologist established a simple system for
  classifying and naming organisms.
• Linnaeus developed a hierarchy (a ranking system)
  for classifying organisms that is the basis for
  modern taxonomy.

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When Was Classification Started?

• In his system of classification, he ranked
  categories from the broadest and most general
  (kingdoms) to the smallest and most specific
  (species).
• Linnaeus also used Latin for the names of the
  categories and species because this was the
  language of educated people and not an everyday
  language that would be likely to change.

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When Was Classification Started?

• Additionally, Linnaeus used an organisms form and
  its structures to categorize it. 
• Linnaeus is called the Father of Modern Taxonomy
  because his system is still being used today.

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How Does Classification Work?

• By learning the Hierarchy and the Naming Process
  the system becomes more clearly understood.

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A) The Hierarchy System

• Linnaeus's classification hierarchy included FIVE
  levels and modern scientists have added TWO more
  classifications levels.

A. KINGDOM B. PHYLUM/DIVISION C. CLASS D.
ORDER E. FAMILY F. GENUS G. SPECIES
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A) The Hierarchy System

• How can you remember this?
• KING PHILIP CAME OVER
• FOR GOOD SPAGHETTI.

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B) The Naming Process

• To ensure accurate communication of information,
  Linnaeus proposed a system of scientific naming
  using TWO names for each organism.
• This naming system is referred to as Binomial
  Nomenclature.

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B) The Naming Process

• The FIRST word (genus) of a scientific name is a
  description of the group of organisms to which
  the individual belongs.

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B) The Naming Process

• The SECOND word (species) of a name is a general
  description of the organism, usually an important
  characteristic it contains, or where it is
  located.

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B) The Naming Process

• When we use the Latin name for an organism, we
  always capitalize the Genus but not the species
  identifier.
• We also print the name in italics or underline
  them.
• The scientific name can be abbreviated. For
  example
• 1) Homo sapien H. sapien
• 2) Canis familiaris C. familiaris

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How Do We Classify Organisms?

• When placing an organism into a group taxonomists
  consider its
• Morphology (appearances behaviors)
• Chromosomal Characteristics (traits)
• DNA/RNA Amino Acid Sequences (genes)
• Embryological Development (life-cycles)
• Fossil Records (past histories)
• All of the above are used to yield reliable
  information about the PHYLOGENY or evolutionary
  history of an organism.

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How Do We Classify Organisms?

• Classification is based on the fact that
  different degrees of similarities exist among
  organisms.
• Organisms are similar because the have descended
  from common ancestors.
• Thus, the more similar organisms are the more
  classification categories they belong together in.

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How Do We Classify Organisms?

• TWO Approaches
• SYSTEMATICS (Family Trees) show relationships
  thought to exist among groups of organisms.

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How Do We Classify Organisms?

• TWO Approaches
• 2) CLADISTICS (Cladograms) a new system that
  uses certain features of organisms called, shared
  derived characteristics, to show relationships.

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The Kingdoms of Life

• Linnaeus classified all organisms into TWO
  kingdoms, Plants and Animals.
• Modern scientists use SIX kingdoms.

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Kingdom Monera

• Archaebacteria and Eubacteria are sometimes
  combined together into one kingdom called Monera.
• Together they include the greatest number of
  living things on the Earth.
• All members are classified as prokaryotes and
  reproduce by binary fission.

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1) Kingdom Archaebacteria

• The prefix archae means ancient."
• Modern Archaebacteria may be directly descended
  from the first organisms on Earth.
• They are unicellular prokaryotes with distinctive
  cell membranes that lack peptidoglycan.
• Some are autotrophic, but most are heterotrophic.
• Many Archaebacteria live in harsh environments
  such as sulfurous hot springs, very salty lakes,
  and in anaerobic environments, such as the
  intestines of mammals.

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2) Kingdom Eubacteria

• The prefix eu means true.
• They are unicellular prokaryotes that have cell
  membranes that contain peptidoglycan.
• Eubacteria are both autotrophs and heterotrophs.
• Eubacteria are most often the bacteria (germs)
  that affect your life such as those involved in
  tooth decay or food poisoning.

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3) Kingdom Protista

• Referred to as The Ash and Trash Kingdom
• Theses organisms are placed here more because of
  what they are not than what they are. 
• The Kingdom Protista contains all eukaryotes that
  are not plants, animals, or fungi.
• There are more than 50,000 species in the kingdom
  which include unicellular and a few multicellular
  eukaryotes like Euglena and Amoebas.

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4) Kingdom Fungi

• Fungi are eukaryotes and most are multicellular.
• The cells of fungi have cell walls that contain a
  material called chitin.
• These organisms are heterotrophic and obtain
  nutrients by releasing digestive enzymes into a
  food source. They then absorb their food after it
  has been digested by the enzymes.
• Fungi act either as decomposers or as parasites
  in nature and include molds, mildews, mushrooms,
  and yeast.

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5) Kingdom Plantae

• Plants are eukaryotic, multicellular and carry
  out photosynthesis.
• The cells of plants have cell walls, that contain
  cellulose.
• Plant cells are specialized for different
  functions, such as photosynthesis, the transport
  f materials, and support.
• Plants include mosses, ferns, gymnosperms
  (cone-bearing plants) and angiosperms (flowering
  plants).

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6) Kingdom Animalia

• Animals are multicellular, eukaryotic and
  heterothophic.
• Animal cells have no cell walls.
• Most members of the Animal Kingdom can move from
  place to place. Although some are permanently
  attached to surfaces such as sponges and
  barnacles.
• Animals include fish, birds, reptiles,
  amphibians, and mammals (including humans).

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Kingdom Relationships

• The kingdom development is thought to look
  something like shown below

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Any Questions?

• If you dont like the way the world is, you
  change it. You have an obligation to change it.
  You just do it one step at a time. --Marian
  Wright Edelman
• The best way to have a good idea is to have lots
  of ideas.
• --Linus Pauling