In this introductory activity, students graph and analyze data, observing trends and change over time. The data set consists of leaf thickness measurements taken 4 times during a growing season and the number of fruits produced by plants with each thickness of leaf. The graphical data visualization can be the lead-in to more advanced statistical analysis for comparing differences among groups. With the data provided, students see a shift in the number of plants for each thickness—the thick-leafed plants increase in number and produce more fruit. Students are asked to use the data to make an argument for natural selection in the plants grown on Eorthe.
These are examples of leaves. How can they be used as evidence for adaptation among plants?
HS-LS4-3. Apply concepts of statistics and probability to support explanations that organisms with an advantageous heritable trait tend to increase in proportion to organisms lacking this trait.
No PPE is required for the activity.
Copy the student pages or upload to a class webpage.
What is the percent abundance of each variety of XR-45 at spring 1 of 3030, at summer 2 of 3030, 3031, 3032, 3033?
Use the data, statistics, and graph to explain the trend in abundance of each variation in leaf thickness within the 1000 plant samples.
Student answers will vary, but all students should explain the increase in population for the thick leaf variation of XR-45 and the decrease in the other 2 varieties. Student answers must contain the numeric values they calculated.
Use the data, statistics, and graph to explain the trend in abundance of fruit for each leaf thickness variation within the 1000 plant samples.
Student answers will vary and must contain numerical support for their statements. The thick leaf plant is producing more fruit and the other 2 varieties are showing fruit reduction at about the same rate.
Explain the difference in fruit production among the 3 variations of plant leaf thickness that could lead to increased survival.
The plant variety with the thicker leaf produces more fruit. By producing more fruit, the plant produces more seeds, which increases the probability of survival for that variety. The evidence supports this because there is an increasing number of the thick leaf variety every year.
Use your data to explain if natural selection and adaptation may be taking place in the plants since being transplanted to Eorthe.
Student answers will vary and must contain numerical support for their statements. Natural selection and adaptation are probably taking place on Eorthe.
Environmental changes that affect the growth of XR-45 seem to be impacting the proportion of plants with thicker leaves. The data show_______________ . When two sets of rainy seasons (spring) are followed by a dry season (summer), conditions appear to favor the plant variety that can retain water in its leaves, as evidenced by _______________.
In turn, those plants can produce more fruit because there is adequate water stored in the leaf. More fruit production from the thick-leafed variety of XR-45 means that those genes will be passed on. This fits the definition of natural selection and adaptation.
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