Novak &Rowland: Bio B
Variation Lab
How Patterns of Variation Relate To Evolution
Purpose – In this lab you will investigate variations in sunflower seeds and humans and how they relate to the
survival of a species. To do this, you will measure the length of a sunflower seed, and the length of your hand
spread from the tip of your thumb to your little finger. You will graph the data and analyze your results.
Predictions –
Predict the shape of the graph of the variation of each of the traits that you are measuring. For each trait, explain
why you expect to see your predicted shape.
Procedure –
1. Get 1 cup full of sunflower seeds.
2. Using a metric ruler, measure (in mm) the length of the sunflower seed.
a. Round to whole number.
3. Record your measurements on a data table on a separate piece of paper.
Part 2: Hands
1. Using a metric ruler, measure (in cm) the length of your hand spread apart from your thumb to your little
finger. Repeat with both hands and do the same for your partner’s as well.
2. Create a data table for you and your partner’s measurements AND for the class data.
Data Tables
HANDS
Person
Left Hand
Right Hand
CLASS HAND DATA
SIZE
Frequency
SEEDS (make a data table)
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Novak &Rowland: Bio B
Graphing Instructions –
1. Create two separate bar graphs.
Conclusions – Use complete sentences to answer.
1. Looking at each of the graphs, what effect does sample size have on the shape of the graph and the validity
of the information? Are there any reasons why the data in this lab may not give us a perfect bell shaped
curve even though it may exist in the entire population?
2. Why might the extremes in length be beneficial in a population?
Sunflower Seed –
Human –
3. A new population of birds has migrated into the sunflower’s natural environment. These birds have a new
favorite meal – large-sized seeds. Over time, how might these birds affect the gene pool for the length trait
in this population of sunflowers?
4. How long do you think it will take for any changes (use question #3) in the population’s average length to
be noticed and WHY?
5. How does variation among individuals relate to evolution (change in genetics over time)? Explain how
variation in a population leads to a change in the relative frequencies of alleles, and could lead to the
formation of a new species. (A complete answer should be at least a paragraph in length.)
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