Evolution in Action Questions
1.
a. What observations can you make about the overall shape of each graph? (Imagine that
you are drawing a line that connects the tops of the horizontal bars.)
i. They all look like normally distributed bell curves when drawing a line across the
top of the bars
b. What do the shapes of the two graphs indicate the distribution of beak depth
measurements in these two groups of medium ground finches?
i. The beak depth trait among all the birds is extremely variable. Most beak depth
values are around the mean
2. Compare the distribution of beak depths between survivors and nonsurvivors. In your answer,
include the shape of the distributions, the range of the data, and the most common measurements.
a. Both graphs appear to be similar shapes but they aren't distributed in the same way, the
groups have a different range than each other. The nonsurvivors had a range of 7.25mm
to 11.25mm while the survivor's range was 8 to 11.25. The mean beak depth of birds that
did not survive was 9.11mm while the ones who did survive had a mean of 9.67mm.
3. Based on what you saw in the film, think about how changes in the environment may have
affected which birds survived the drought. Propose a hypothesis to explain differences in the
distribution of beak depths between survivors and non-survivors.
a. The birds experienced a drought forcing them to change their food source. Birds with
larger beaks were better able to use these large seeds as food, so they are better adapted,
than were birds with smaller beaks
4. Let’s look in more detail at the mean beak depths in the two groups of birds to understand the
meaning of standard deviation.
a. How do the mean beak depths and standard deviations of the mean beak depths compare?
1.
a. What observations can you make about the overall shape of each graph? (Imagine that
you are drawing a line that connects the tops of the horizontal bars.)
i. They all look like normally distributed bell curves when drawing a line across the
top of the bars
b. What do the shapes of the two graphs indicate the distribution of beak depth
measurements in these two groups of medium ground finches?
i. The beak depth trait among all the birds is extremely variable. Most beak depth
values are around the mean
2. Compare the distribution of beak depths between survivors and nonsurvivors. In your answer,
include the shape of the distributions, the range of the data, and the most common measurements.
a. Both graphs appear to be similar shapes but they aren't distributed in the same way, the
groups have a different range than each other. The nonsurvivors had a range of 7.25mm
to 11.25mm while the survivor's range was 8 to 11.25. The mean beak depth of birds that
did not survive was 9.11mm while the ones who did survive had a mean of 9.67mm.
3. Based on what you saw in the film, think about how changes in the environment may have
affected which birds survived the drought. Propose a hypothesis to explain differences in the
distribution of beak depths between survivors and non-survivors.
a. The birds experienced a drought forcing them to change their food source. Birds with
larger beaks were better able to use these large seeds as food, so they are better adapted,
than were birds with smaller beaks
4. Let’s look in more detail at the mean beak depths in the two groups of birds to understand the
meaning of standard deviation.
a. How do the mean beak depths and standard deviations of the mean beak depths compare?
