Biology Notes Chapter 15

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					    Biology Notes Chapter
             15
           Classification Systems




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                Why Classify?
   In order to work with the diversity of life,
    we need a system of biological
    classification that names orders living
    organisms in a logical manner.
     – There are more than 2.5 million species
       already identified and millions more possibly
       undiscovered.
     – Scientists use a universal method of naming
       organisms, so that no matter where in the
       world you may go, the names of the different
       organisms will be the same.

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           Biological Classification.
   Carolus Linnaeus, is the father of the modern
    classification system used by scientists.
     – Linnaeus came up with the system of
       binomial nomenclature, which is a two-
       name system.
         The two names are the genus and species of
          an organism.
            – The genus is always capitalized and the species is
              never capitalized.
                Both names are always printed in italicized
                 letters.


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           The Classification System of
                    Linnaeus
 The  branch of science of naming
   organisms and assigning them to
   groups is called taxonomy.
     – Organisms are classified into groups of
       differing levels of relatedness.
     – The levels of relatedness from the most
       broad to the most specific are:
            Kingdom,phylum, class, order, family,
            genus, species

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                   Species
 Species   is the most specific of the
   levels of relatedness.
     – Species is defined as a population of
       organisms that share similar
       characteristics and that can breed with
       one another and produce viable
       offspring.




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                      Genus
 The next larger taxon is the genus.
 All the various species included in the
  same genus have many common
  characteristics.
     – For example the common house cat has the
       genus Felis and the species domesticus. The
       mountain lion has the genus Felis and the
       species concolor.
     – These two cats share many common
       characteristics, but they are not able to
       interbreed and produce viable offspring.


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                    Family
A   family is a larger taxon than genus
   or species.
     – All members of a genus will belong to
       the same family.




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                        Order
 Several families of similar organisms
   make up the next larger group called
   order.
     – For example cats are in the order
       Carnivora.
              members of the order Carnivora are
            All
            meat eaters or carnivores.




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                        Classes
 Orders           are grouped into classes.
     – Classes are based on common
       characteristics to many orders.
               example, warm blooded animals that
            For
            have hair are members of the class
            Mammalia.




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                          Phylum
 Several         classes are placed in a
   phylum.
     – A phylum will consist of a large number
       of very different organisms.
            Theseorganisms share some important
            characteristics.
             – For example mammals are placed in phylum
               Chordata along with birds, fishes, and reptiles
               because all of them share certain similar
               characteristics.



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                 Kingdoms
 Kingdom   is the largest broadest
   group wit the least amount of
   relatedness.
     – Different kingdoms are those such as
       Plantae, Animalia, Fungi, Protista,
       Monera




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       Memory Aid For The Different
         Levels Of Organization
 The phrase “King Phillip Came Over
  For a Good Supper” may help you
  remember the different levels of
  organization.
 Kingdom, Phylum, Class, Order,
  Family, Genus, Species




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           Taxonomy And Evolutionary
                 Relationships
 Species shown to be closely related are
  classified together.
 Other species that may look alike but
  possess analogous structure only, are
  classified in different groups.
 Taxonomists attempt to group organisms
  in ways that show their evolutionary
  relationships.
     – They do this by identifying and studying
       homologous structures in adult organisms, in
       developing embryos, and in well preserved
       fossils.

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           Biochemical Taxonomy
 All organisms share many important
   organic molecules that are almost
   but not exactly identical from species
   to species.
     – Mammals, birds, amphibians, reptiles,
       and fishes have hemoglobin in their
       blood, but each species has a slightly
       different variety of it.


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            Biochemical Taxonomy
 Biochemists   use these similarities
   and differences among the
   compounds of life to classify
   organisms.
     – The can use DNA and RNA to classify
       organisms.
            For example studies of DNA show that
            humans and chimpanzees have DNA that
            differs in less than 1% of their nucleotide
            sequence.

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           The Five Kingdom System
 The   five kingdoms are Monera,
   Protista, Fungi, Plantae, and
   Animalia.




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                   Monera
 The  kingdom Monera, contains all
   prokaryotes.
     – Prokaryotes lack a true nucleus,
       mitochondria, and chloroplasts.
     – Monerans are placed at the bottom of
       the evolutionary tree or ladder.




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                      Protista
 Unlike prokaryotes, all eukaryotes possess
  membrane-enclosed organelles, and
  contain a true nucleus.
 All single celled eukaryotes are placed in
  the kingdom Protista.
 The kingdom Protista is divided into three
  groups.
     – Animal like protists
     – Plant-like protists
     – Fungus like protists


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                        Fungi
 Members of the kingdom Fungi build cell
  walls that do not contain cellulose.
 Fungi are heterotrophic, which means
  that they do not make their own food by
  photosynthesis.
 Although fungi have many nuclei, they do
  not always have separate cells divided by
  complete cell walls.
     – It is for these reasons that fungi are not
       included with the plants and are placed in their
       own kingdom.

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                  Plantae
 Members    of the kingdom Plantae are
   multicellular
     – They have cell walls that contain
       cellulose.
     – They are autotrophic which means
       they make their own food in
       photosynthesis.



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              Animalia
 Members   of the Animalia kingdom
  are multicellular.
 They are heterotrophic.

 All have cell membranes without cell
  walls.




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                 Test Review
   The scientific name for a __ would be Homo
    sapiens.
   The smallest taxon is __.
   The difference between a plant and a plant like
    protists is that the protists is ___.
   The animal that has the closest DNA match of a
    human is the __.
   A eukaryotic organism that has a cell wall that
    lacks cellulose is a (an) __.
   In the present system of taxonomy, the least
    clear division of kingdoms is between the
    multicellular kingdoms and the ___.

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              Test Review
 All Monerans contain a __. (chloroplast,
  cell membrane, nucleus, mitochondria)
 Any good classification systems does not
  use different scientific names for the same
  organism. (True or False)
 The double naming system introduced by
  Linnaeus is know as _.
 Many species of protists straddle the line
  between single celled and multicellular
  plans, animals, and fungi. Why are these
  species so important to biologists?

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              Test Review
 Why is it more difficult to classify a newly
  found fossil of an animal than newly found
  living animals?
 Why are organisms sometimes moved
  from one taxon to another?
 A newspaper article states that a new
  blend of Milo wheat will be planted next
  year. This blend was developed by
  crossbreeding different types of wheat.
  This article is referring to a new species of
  wheat. How do you know that this will be
  a new species instead of a new genus.

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              Test Review
 Describe the relationship between the
  common housecat, Felis domesticus and
  the African leopard, Felis pardus.
 The unifying biological principle in modern
  classification systems is the __ theory.
 Carnivores are __

 If a one celled organism contains
  membrane enclosed organelles , it must
  be a __.

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                  Test Review
     The only taxon with a clear biological identity is
      the __.
     Cats, dogs, and lions are in the ___ order.
     In classifying organisms, orders are grouped
      into __.
     Solely from its name, you know that Rhizopus
      niqricans must be
a. a plant     b. an animal      c. In the species niqricans
     The third smallest taxon in the Linnaeus system
      of classification is the __.


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