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 l 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

Length Class §The graph illustrates the distribution of the length of seeds sampled l 80% of individuals sampled are larger than 7cm

Frequency Distribution of the Width of seeds of Cedrela odorata

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

Weight Class §The weight within the seeds sampled extends over a large range ( g) §The largest proportion are found in the range

Summary of the Results obtained from each Group describing Phenotypic Variation

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