Classification

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					        Classification


       TAXONOMY: HIERARCHY
DOMAINS: PROKARYOTES VS. EUKARYOTES
              Why do we classify?

Because there are so many known species, a system of
 classification is needed for 3 reasons:

      a.    Organize species into groups and
             discuss them.
      b.    Identify new organisms.
      c.    Show relationships between organisms.
                How do we classify

Evidence for evolution    Why?


 Biochemical              -those with similar
 Anatomy
                            DNA are more closely
                            related
 embryology
                           -those with similar
                            physical properties are
                            more related
                           Those that looked
                            similar at birth more
                            related.
             Homologies (structures)

Recall:                        Anatomy


 Similar structure             In the earlier days,
  means common                  scientists like Carolus
  ancestor                      Linnaeus based
 The more homologies           classification on
  two organisms possess,        physical features
  the more likely it is that
  they have a close
  genetic relationship
                   Class activity



 Write your description
 based on 5 physical
 characteristics.
                        Classification

How many species are               Who came up with a
there                              system?

 13-14 million species             Carlus Linnaeus
   Majority are microscopic          Came up with a system for
    probably haven't even              describing and naming
    seen before                        species
   1.8 millions have scientific      Invented a system of
    names                              classification
                          Carlous Linneau


 Developed a system of hierarchy
 A system of ranking and organizing species
 There are 8 ranks ( taxons) to the hearty
   Taxon: group of organisms with an evolutionary relationship

   Domains, kingdom, phylum, class, order, family, genus,
    species

     Mnemonic: dignified kings play chess on fine green silk
         Make your own
                 Taxonomic heirchay

Domains                         Kingdom


 Based on cell type             Based on cellular
   Eukaryotic Vs prokaryotic     organization
                                     Single vs. multi cellular
                                 Mode of nutrition
                                   Make own food or get food
                                    from other sources: how
                                    does it obtain food
                                         Ex: absorb, ingest
                   Taxonomy heirchy

Phylum                            Class


 based on basic body              Based on: Skeletal
 plan: internal                    system, general
 organization                      environment
   -Hard bodied vs. soft bodied    adaptation and
                                   reproductive system
                                      How they reproduce and
                                       care for young
                              SPECIES:


 ORDER                        Can reproduce to
 FAMILY                       produce fertile
 GENUS
                               offspring
 SPECIES


      INCREASED SIMILARITY
                Binomial classification

                               Example:

                                  Domain: Eukaryota (organisms which have cells with a
 Uses the genus and           
                                   nucleus)
                                   Kingdom: Animalia (with eukaryotic cells having cell
                                   membrane but lacking cell wall, multicellular,
 species name:                 
                                   heterotrophic)
                                   Phylum: Chordata (animals with a notochord, dorsal
                                   nerve cord, and pharyngeal gill slits, which may be
    Ex: humans                
                                   vestigial)
                                   Subphylum: Vertebrata (possessing a backbone, which
                                   may be cartilaginous, to protect the dorsal nerve cord)
    the scientific name for      Class: Mammalia (endothermic vertebrates with hair
                                   and mammary glands which, in females, secrete milk to
     humans is Homo sapiens.   
                                   nourish young)
                                   Cohort: Placentalia (giving birth to live young after a full
     (Genus Homo=man,          
                                   internal gestation period)
                                   Order: Primates (collar bone, eyes face forward,
     specific epithet              grasping hands with fingers, and two types of teeth:
                                   incisors and molars)
                                   Family: Hominidae (upright posture, large brain,
     sapiens=thinking.
                               
                                   stereoscopic vision, flat face, hands and feet have
                                   different specializations)
     Literally, in Latin,      
                               
                                   Genus: Homo (s-curved spine, "man")
                                   Species: Homo sapiens (high forehead, well-developed
     thinking man                  chin, skull bones thin)
                                           Humans

   Domain: Eukaryota (organisms which have cells with a nucleus)

   Kingdom: Animalia (with eukaryotic cells having cell membrane but lacking cell wall, multicellular,
    heterotrophic)

   Phylum: Chordata (animals with a notochord, dorsal nerve cord, and pharyngeal gill slits, which may
    be vestigial)

   Class: Mammalia (endothermic vertebrates with hair and mammary glands which, in females, secrete
    milk to nourish young)

   Order: Primates (collar bone, eyes face forward, grasping hands with fingers, and two types of teeth:
    incisors and molars)

   Family: Hominidae (upright posture, large brain, stereoscopic vision, flat face, hands and feet have
    different specializations)

   Genus: Homo (s-curved spine, "man")

   Species: Homo sapiens (high forehead, well-developed chin, skull bones thin)
                              Domains:

3 domains of life


 3:
   Archea: extreme bacteria
         Prokaryotic cells
     Prokarya or bacteria
         Prokaryotic cells
     Eukaryota:
         Eukaryotic cells
                      Prokaryotic cells

Archea                          Bacteria


 Microorganism that             More advanced forms
 live in extreme                 of bacteria
 environments
    Primitive e forms of
     bacteria
    hot springs
                 Prokaryotic Cells

 (1)    Prokaryotic cells are smaller and more
  primitive.
 (2)    They have few organelles and their organelles
  have no membranes. The cell has no nucleus. Many
  prokaryotes have a rigid cell wall. They are able to
  grow and multiply quickly because of their small
  surface area: volume ratio.
 (3)     They are bacteria and cyanobacteria (blue-
  green algae).
                  Eukaryotic Cells

 1) are more advanced, larger, and contain organelles.
  These cells have a nucleus. All species other than
  bacteria and cyanobacteria are eukaryotes. This
  includes protists, fungi, plants, and animals, as well
  as humans.
 2) Organelles allow many activities to take place
  within the same cell
                   comparison

                          Eukaryotes
Prokaryotes


                           Have a Nucleus that
 No Nucleus---Genetic      contains Genetic
  Information Floats        Information
  around in Cytoplasm      Have Membrane-
 No Membrane-Bound         Bound Organelles
  Organelles               Generally Larger in size
 Much Smaller in size     Very Complex
 Very Simple Structure     Structure

				
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posted:10/7/2011
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