STUDY  of   LIFE   (Biology 150 - University of Miami)      


                                                                                                  
 Course is divided into (3) parts:                                                   
 

    1)     Cellular & Molecular Biology                    
    2)     Cell Reproduction & Genetics                    
    3)     Homeostasis & Physiology                       

                FIRST PART of our study will be...
                             " a Journey thru the COSMOS of the CELL "  

next page
                                                                                                                            click for next page

 

 

 

 

 

 

   
 Modern Biology is often described as...                             the BIOCHEMISTRY of the CELL

       modern Biology commonly uses a different approach
                                                  than you may used before for studying Biology -
      
       more common approach has been to look at DIVERSITY...
                                          the kinds of plants & animals known to exist -
   

 
             whole of biology is a counterpoint of two themes:
                      astonishing variety in
individual particulars (species);
                      astonishing consistency  in
fundamental mechanisms.
   
       Bil 150's current approach to modern biology is to stress...
   
                                              the UNIFYING CONCEPTS of Biology.
   

next page

 

 

 

 


 

  

In my opinion,
               there are 3 UNIFYING CONCEPTS,                
                which stress the UNITY of LIFE...  
                                                                 
[ Campbell describes 10  themes ]

               1.  CELL THEORY

                  2.   EVOLUTION

                       3.    BIOENERGETICS (energy transformation)

 

   next pagenext page

 

 

 

 

     

 1.    CELL THEORY
         (
cell doctrine)
               

 1st cells described by R. Hooke in 1663 ( ^ cork cells)  &  Leeuwenhoek 1673
                                                           [an essay on Hooke's life work]                     bacteria & spirogyra
   in 1670 Marcello Malphigi suggests that plant leaves & stems are composed of cells

   by 1805 Lorenz Oken, a German natur-philosopher, claims all organisms consist of cells
  
       but, Cell Theory formally espoused in 1839.....                 
               by  Matthais Schleiden (lawyer turned botanist) &                
*
                     Theodor Schwann    (animal embryologist)          [met at dinner party in 1837]
  
   in 1858 Rudolph Virchow forcefully states a major paradigm of this new cell theory...
       "All cells arise from pre-existing cells"
       Thus:  all individuals derived from a single celled organism are related &
                         all cells in a multi-celled organism are descended from one fertilized egg.
next pagenext page
   

    


 

 

  
     Tenets of the Cell theory  -   Universal Features of Cells on Earth

  
    Some important facts about cells (virtual cells  -  Kyrk's Cell Animations
more later):
        - their diversity : - many sizes, shapes, & types [165+ in humans]  no two alike
NAS-6
        - their similarity: - have same basic structural plan
                                   - surrounded by cell membrane
                                   - contain nuclei     (bacteria = genophore = area of DNA)
                                   - similar sub-cell parts (ORGANELLES)
                                   - all contain
     universal properties of all cells*

     next pagenext page

 

 

 

 
 2.  EVOLUTION..."Descent with modification"  
                                      "Nothing in biology makes sense except in the light of evolution"
                   
                      
Theodor Dobzhansky (1973) in Am
er. Bio Teacher 35:125-129
  
 
 
   Evolution is simply a change in natural/physical characteristics of a population over time
  

    In 1858 Charles Darwin & Alfred Russell Wallace present papers to Linnaean Society
   with 2 important new hypotheses about biological PATTERNS in the natural world.
        ... all species (past & present) are related by descent from common ancestor
        ... hypothesized all species come from preexisting species & they change through time
      
         -  individuals in a population vary in hereditable traits...
(look around class) 
       
        -  this accounts for the diversity we see in biology... 
       
        -  living things change gradually over time to become new forms...

                        from one form      ------------------>     to another form
                      (oneLadybug.gif (2206 bytes)SPECIES)     -------->        (New Crawlbug.gif (343 bytes) SPECIES)

    Darwin proposed a PROCESS (mechanism) for this (PATTERN) descent & change...

next pagenext page

 

 

 
 
 
 
 
 
 MECHANISM - is via NATURAL SELECTION (SURVIVAL of FITTEST)
   

     -  individuals in a population vary in hereditable traits...
 

    -  some traits help individuals survive better or reproduce more.

  

    -  Natural Selection picks those individuals better fit to specific environment...

            only those with superior traits   (physical, behavioral, biochemical
            are more likely to
SURVIVE and REPRODUCE... 
      
                            passing their traits onto their progeny more efficiently
  

    - over time... a whole population's characteristics can change
                                      
see an example of natural selection with a predation model*
  
    

next pagenext page

 

 

 

 

 

 

 Examples of SELECTION:  
  
Artificial Selection.... examples
     
 in Cabbage Plants*... 
                   broccoli, cauliflower, Brussels sprouts, cabbage, kale, and
                   collard greens are all derived from Wild Mustard plants
                   horticulturalists SELECT* wild mustards with large buds = Brussels sprouts
  
  Natural Selection.... examples
       case study 1* - Peter & Rosemary Grant & medium ground finch

       
case study2   - feeding preferences of different predators does cause changes in guppy
                            
populations favoring long-term evolutionary changes by natural selection
                                
David Reznick (UCR) & John Endler (UCSB) - Trinidadian guppies
                                                                                  experimental design and results*    
                                 
 
Student Media - Process of Science: Selection or How environment affects populations*

     UNITY...   Comes from fact that all living things changed,            a theory
           
                               evolved by same rules, the Laws of Evolution          Evolution of Humankind
    

next page

 

 

 

 

     
3. 
BIOENERGETICS - (science of EQUILIBRIUM THERMODYNAMICS)...
             science of energy flow and transformation 
                                                                    within, through, and between organisms... 

           "
cells do not produce energy - they consume energy"

UNITY comes from the fact that the mechanisms of
                         energy change and flow are NOT different
                                            among different life forms, but are the SAME
              
                methane.gif (3255 bytes)
    glycolysis,   Krebs's cycle,   oxidative phosphorylation,  &
    photosynthesis  
ARE UNIVERSAL

   Unity...chemical reactions of life are the same in bacteria, plants, animals 

next pagenext

 

 

 

 

 

 

 

      

 
dna_bar2.gif (19216 bytes)
        the CELL is FUNCTIONAL UNIT of LIFE & of all known LIVING SYSTEMS
dna_bar2.gif (19216 bytes)
              CELL THEORY is to BIOLOGY as ATOMIC THEORY is to PHYSICS 
dna_bar2.gif (19216 bytes)
     Definitions of a Cell : 
    
     A particular organization of
       matter, bounded by a selectively
       permeable membrane, that is
       capable of self-reproduction,
       without the presence of other
       living organism.
(eliminates viruses).
"Living organisms are composed of
  inanimate molecules... and nothing is
  alive in a cell except the whole of it?"
         Matrin Olomucki (1993)
            The chemistry of life.  NY, McGraw Hill 

paradigm - an archetype model* 

end of this chapter
       U of Miami Home Page  |  Biology Home Page  |  Dr. Mallery's Home Page  |  On-Line Testing Center. 
          copyright c2005,   Charles Mallery Biology 150, Department of Biology, University of Miami, Coral Gables, FL 33124
          Last Update - September 04, 2008
        
back to handouts page