Phenotypic Variation: Examining the Seeds of Cedrela odorata

1
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

2
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

3
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

4
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

5
Results
6
Frequency Distribution of Length of the seeds of
C. odorata
7
Length Class

• The graph illustrates the distribution of the
  length of seeds sampled
• 80 of individuals sampled are larger than 7cm

8
Frequency Distribution of the Width of seeds of
Cedrela odorata
9
Width Class

• The majority of seeds sampled are less than 4cm
  in width
• A small proportion exceed this value

10
Frequency Distribution of the Weight (g) of the
seed C. odorata
11
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

12
Summary of the Results obtained from each Group
describing Phenotypic Variation
13
Averages

• Average length - 7cm
• Average width - 4cm
• Average weight - 25g

14
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