EVOLUTION QUESTION 1994:			L.PETERSON/AP BIOLOGY

     Genetic variation is the raw material for evolution.
     a.  	Explain three cellular and/or molecular mechanisms that introduce variation 
	into the gene pool of a plant or animal population.
     b.  	Explain the evolutionary mechanisms that can change the composition of the gene pool.
  
  
     2 points maximum for each category
          1 point for general explanation and 1 point for elaboration
  
     The second point may be earned with an elaboration or an explained example.
  
  PART A (6 POINTS MAX)            PART B (6 POINTS MAX)
  Eplain three cellular and/or molecular     Explain the evolutionary mechanisms
  mechanisms that introduce variation   that can change the composition of the
  into the gene pool of a plant or animal    gene pool.
  population.
                              1+1  Natural selection explanation
  1  Mutation is a change in the DNA         Minimum:
                                   Differential reproductive success
  1  Mutagenesis   explanation          (Survival of the fittest not enough)
                                   Elaboration:
  1+1     Point mutations                               Adaptation viewed as a "result"
  1+1     Substitution                                  Adaptive radiation
  1+1     Frame shift                                   Importance of variation
        Insertion                                  Occurs in populations
        Deletion                        Example
  1+1     Editing error (repair)
                              1+1  Gene Flow
  1+1      Chromosomal mechanisms            Minimum:
  1+1     Translocation (Transposition)           Immigration or emigration of alleles
  1+1     Inversion                     Elaboration:
  1+1     Deletion                      Outbreeding
  1+1     Duplication                        Geographic isolation
  1+1     Crossing over                      Barriers   addition/removal
     (new combinations of linked alleles)         geography/temporal/reproductive
  1+1     Aneuploidy (non-disjunction)            behavioral
  1+1     Polyploidy                         Example
  
  1+1     Other Mechanisms              1+1  Genetic Drift (Neutral Selection)
  1+1     Transposable elements              Minimum:
  1+1     Virus induced changes                   Non representative, random change
  1+1     Genetic engineering                in allelic frequency   linked with small
                                   population size
  1+1     Sexual reproduction           Elaboration:
     Meiosis as a reshuffling mechanism      Bottleneck effect, founder effect
     Recombination of genes (alleles)        Effect of a small population
     Independent assortment             Example
     Random fertilization                    
     Cross breeding           1+1  Mutation
     (Elaboration point is for gene pool          Minimum:
     connection not for individual variation)          (change in genes or alleles in context
                                   as an evolutionary mechanism)
                                   Elaboration:
                                   Randomness
                                   Non-directionality
                                   Change in phenotypic traits
                                   Gametic not somatic change
                                   Example
  
                              1+1  Assortive mating
                                   Minimum:
                                   non-random / choice
                                   Elaboration:
                                   Sexual Selection
                                   Artificial Selection
                                   In-breeding
                                   Example