Phenotypic Variation Examining the Seeds Cedrela odorata

							Phenotypic Variation: Examining
  the Seeds of Cedrela odorata
                Nate and Crystal
   Natural Selection and Evolution: Phenotypic Variation
                         Module 3
              Atlantic Forest, Brazil
                  SEE-U 2000
                 Introduction
 Phenotypic Variation: Individuals of the
  same species exhibiting differences in
  morphological characteristics
 We examined phenotypic variation
  exhibited in seeds of the Cedrela odorata
     This tree is common to the Atlantic Forests of
      Brazil and is harvested for its wood products
              Methodology
 90 seeds were randomly selected from one
  tree and sampled by three groups
 Each seed was weighed with a spring
  balance, and the measure of its length and
  width taken with use of a caliper
 Statistical tests were performed in order to
  determine the extent variation among the
  sampled seeds
              Hypotheses
 Null Hypothesis: There is no variation in
  length, width, and weight of the C. odorata
  seeds randomly sampled from the same tree
 Alternative Hypothesis: There is variation
  in the length, width, and weight of the C.
  odorata seeds from the same tree
Results
Frequency Distribution of Length of the seeds
               of C. odorata

                60
  Individuals
  Number of


                50
                40
                30
                20
                10
                 0
                     5       6      7        8

                         Length Class (cm)
                Length Class
 The graph illustrates the distribution of the
  length of seeds sampled
     80% of individuals sampled are larger than 7cm
Frequency Distribution of the Width of seeds
           of Cedrela odorata

               60
 Individuals
 Number of


               50
               40
               30
               20
               10
                0
                    3       4        5

                        Width (cm)
              Width Class
 The majority of seeds sampled are less than
  4cm in width
 A small proportion exceed this value
Frequency Distribution of the Weight (g) of
           the seed C. odorata

               20
 Individuals
 Number of



               15

               10

               5

               0
                    15-17 18-20 21-23 24-26 27-29 30-32 33-35 36-38

                              Weight Class (g)
Weight Class
 The weight within the seeds sampled
  extends over a large range (15 - 38g)
 The largest proportion are found in the 24 -
  29 range
                  Summary of the Results obtained from each
                    Group describing Phenotypic Variation
Measured Values



                  30
                  25
                  20                                                  Sample 1
                  15                                                  Sample 2
                  10                                                  Sample 3
                   5
                   0
                       Average SD - Average   SD -    Average SD-
                        Length Length Width   Width   Weight Weight
                         (cm)         (cm)              (g)

                            Variables Measured
Averages
 Average length - 7cm

 Average width - 4cm

 Average weight - ~25g
       Discussion/Conclusion
 Variation among the length and width is
  less than the variation observed in weight
 Phenotypic Variation among seeds from the
  same tree may be attributable to seed
  position on the tree
 Null Hypothesis was accepted