Preview - From Ecosystems To Speciation

Intro to CODAP

Below is a data analysis tool called CODAP created by educators at the Concord Consortium. Using this computational tool, you will be able to delve deeply into the finch data mentioned on the previous page. When the page loads you will see the basic finch dataset with columns for sex, weight (g), beak length (mm), beak depth (mm). In CODAP we are able to interact dynamically with the data, allowing us to make connections and draw conclusions. We will use this set to answer several questions about these Galapagos finches.

Questions

Please answer the questions below.

Use CODAP to fill out the following data table.

You can see the value of a data point by hovering your mouse over the point.  Use this to find the minimum and maximum beak lengths.

Clicking on the data point will highlight the row in the data table.

Clicking on a graph will cause a toolbar to appear next to it.  You can find and display useful information about the data in a graph using the ruler menu in that toolbar. Click the check boxes for median, mean, and standard deviation to display them on the graph.  You can find their values by hovering your mouse over the display.

If you click and drag to surround points on a graph, they will be selected on all current graphs. You can use this to hide points that you don't want to see. Sometimes CODAP responds slowly and will have a slight delay, so you may need to wait for it to catch up.

Click and drag to select all of the male finches.  Then, on the histogram of beak length, use the eye menu to the right of the graph to hide unselected points.  For clarity, you can also change the title of the graph to "Males" by clicking on the current title in the blue bar at the top of the graph.

What is the mean beak length for male finches?

In order to visually compare two or more subgroups, it can be helpful to have multiple graphs.  Sometimes the points on a new graph will not look the same as those on other graphs. You can change the appearance of the points on any graph using the paintbrush menu to the right of the graph.

In the upper left corner, click the "Graph" button to create a new blank graph. Drag the "Weight" column header from the table to the x-axis of the new graph to create a second histogram and title it "Females".  Using the same method as before, hide all of the points on the new plot that aren't from female finches.  Drag the "Weight" column header to the x-axis of the original graph to replace "Beak Length".

What differences do you notice in the graph of male finches vs. the graph of female finches? Be sure to mention characteristics like shape of the graph and median values.

Another way to compare subgroups is to put categorical data on the y-axis.  Close one of the two histograms and use the eye menu to show all points on the remaining graph.  If you want, you can change the title for clarity.  Then, drag the "Sex" column header to the y-axis of the histogram.

How does the group of finches of unknown sex compare to the male and female finches?

Drag the "Beak Length" column header to the y-axis of the histogram to turn it into a scatter plot.  If you still want an idea of how the male, female, and unknown sex finches compare, you can drag the "Sex" column header to the middle of the plot to change the color of each point to match the sex of the finch.

Based on this plot, what seems to be the relationship between weight and beak length in these finches?

The data above comes from only one species of finch. Why do you think there is variation in the beak lengths and weights of these finches? Think back to some of the earlier lessons when you saw a graph like this.

Notes

These notes will appear on every page in this lesson so feel free to put anything here you'd like to keep track of.